Android Mad - Development Guide for Mobile App Development

Introduction

In this article, we will learn how to create Dropdown in Xamarin.Forms. By default, Android Platform has dropdown called as “Spinner”, but iOS Platform has no dropdown like Android Spinner. In Xamarin.Forms, we have control called as Picker and we all heard about this. We are going to create a custom to achieve, the control like Android Spinner in Xamarin.Forms.

Dropdown in Xamarin.Forms

As per the introduction, we already having a dropdown control called as “Spinner” in Android Platform. Basically Xamarin.Forms control is a wrapper platform specific controls. For Example, Xamarin.Forms Entry is wrapper of EditText in Android and UITextField in iOS. We will go for View Renderer approach to have a new control to wrap a Platform specific control. Click the below link, to know more about view renderer.

Reference

https://docs.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/custom-renderer/view

Without much introduction, we will skip into the coding part of this article.

Coding Part:

Steps:

I have split this part into 3 steps as in the following.

Creating new Xamarin.Forms Projects.
Creating a Dropdown view in Xamarin.Forms .NetStandard Project.
Wrapping Spinner for Dropdown control in Android Project.
Implementation of Dropdown & It’s Demo for Android Platform.

Step 1: Creating new Xamarin.Forms Projects

Create New Project by Selecting New -> Project -> Select Xamarin Cross Platform App and Click OK.

Then Select Android and iOS Platforms as shown below with Code Sharing Strategy as PCL or .Net Standard and Click OK.

Step 2: Creating a Dropdown view in Xamarin.Forms .NetStandard Project

In this step, we will see how to create a dropdown view with required properties.

Create a class named as “Dropdown” and inherit the Dropdown with “View”. That is Dropdown is child of View.
```
public class Dropdown : View
{
 //...
}
```
Then we will create a required bindable properties. First we will see, what are all the properties & events required for dropdown.
1. ItemsSource – To assign the list of data to be populated in the dropdown.
2. SelectedIndex – To identify the index of selected values from the ItemsSource.
3. ItemSelected – Event for performing action when the item selected in the dropdown.

Create a bindable property for the ItemsSource as shown in below.

public static readonly BindableProperty ItemsSourceProperty = BindableProperty.Create(
 propertyName: nameof(ItemsSource),
 returnType: typeof(List<string>),
 declaringType: typeof(List<string>),
 defaultValue: null);

public List<string> ItemsSource
{
 get { return (List<string>)GetValue(ItemsSourceProperty); }
 set { SetValue(ItemsSourceProperty, value); }
}

Create a bindable property for the SelectedIndex as shown in below.

public static readonly BindableProperty SelectedIndexProperty = BindableProperty.Create(
 propertyName: nameof(SelectedIndex),
 returnType: typeof(int),
 declaringType: typeof(int),
 defaultValue: -1);

public int SelectedIndex
{
 get { return (int)GetValue(SelectedIndexProperty); }
 set { SetValue(SelectedIndexProperty, value); }
}

Create a custom event ItemSelected for dropdown control and invoke the event as shown in below.

public event EventHandler ItemSelected;

public void OnItemSelected(int pos)
{
 ItemSelected?.Invoke(this, new ItemSelectedEventArgs() { SelectedIndex = pos });
}

Here, ItemSelectedEventArgs is a child of EventArgs as shown in below.

public class ItemSelectedEventArgs : EventArgs
{
 public int SelectedIndex { get; set; }
}

Full Code of Dropdown View

Here, we will see the full code for dropdown view.

namespace XF.Ctrls
{
    public class Dropdown : View
    {
        public static readonly BindableProperty ItemsSourceProperty = BindableProperty.Create(
            propertyName: nameof(ItemsSource),
            returnType: typeof(List<string>),
            declaringType: typeof(List<string>),
            defaultValue: null);

        public List<string> ItemsSource
        {
            get { return (List<string>)GetValue(ItemsSourceProperty); }
            set { SetValue(ItemsSourceProperty, value); }
        }

        public static readonly BindableProperty SelectedIndexProperty = BindableProperty.Create(
            propertyName: nameof(SelectedIndex),
            returnType: typeof(int),
            declaringType: typeof(int),
            defaultValue: -1);

        public int SelectedIndex
        {
            get { return (int)GetValue(SelectedIndexProperty); }
            set { SetValue(SelectedIndexProperty, value); }
        }

        public event EventHandler<ItemSelectedEventArgs> ItemSelected;

        public void OnItemSelected(int pos)
        {
            ItemSelected?.Invoke(this, new ItemSelectedEventArgs() { SelectedIndex = pos });
        }
    }

    public class ItemSelectedEventArgs : EventArgs
    {
        public int SelectedIndex { get; set; }
    }
}

Step 3: Wrapping Spinner for Dropdown control in Android Project.

In this step, we will see “How to wrap the Android Spinner Control for Dropdown View”.

Create a class file named as “DropdownRenderer” in your android client project and add View Renderer as shown in below.

public class DropdownRenderer : ViewRenderer<Dropdown, Spinner>
{
 Spinner spinner;
 public DropdownRenderer(Context context) : base(context)
 {

 } 
 // ...
}

Then Override the methods “OnElementChanged” and “OnElementPropertyChanged”. OnElementChanged method is triggered on element/control initiation. OnElementPropertyChanged method is called when the element property changes.

Set Native Control to ViewRenderer using SetNativeControl() method in OnElementChanged override method as shown in below.

protected override void OnElementChanged(ElementChangedEventArgs<Dropdown> e)
{
 base.OnElementChanged(e);

 if (Control == null)
 {
  spinner = new Spinner(Context);
  SetNativeControl(spinner);
 }
 //...
}

Set Items Source from Xamarin.Forms Dropdown to Android Spinner control using array adapter as shown in below.

var view = e.NewElement;

ArrayAdapter adapter = new ArrayAdapter(Context, Android.Resource.Layout.SimpleListItem1, view.ItemsSource);
Control.Adapter = adapter;

Set default selection of item from selected index as shown in below.

if (view.SelectedIndex != -1)
{
 Control.SetSelection(view.SelectedIndex);
}

Create an item selected event for spinner and invoke the dropdown event created as shown below

// ...
Control.ItemSelected += OnItemSelected;
// ...
private void OnItemSelected(object sender, AdapterView.ItemSelectedEventArgs e)
{
 var view = Element;
 if (view != null)
 {
  view.SelectedIndex = e.Position;
  view.OnItemSelected(e.Position);
 }
}

In the same way, we will assign ItemsSource & SelectedIndex to Android Spinner when the property changes using OnElementPropertyChanged as shown below.

protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
 var view = Element;
 if (e.PropertyName == Dropdown.ItemsSourceProperty.PropertyName)
 {
  ArrayAdapter adapter = new ArrayAdapter(Context, Android.Resource.Layout.SimpleListItem1, view.ItemsSource);
  Control.Adapter = adapter;
 }
 if (e.PropertyName == Dropdown.SelectedIndexProperty.PropertyName)
 {
  Control.SetSelection(view.SelectedIndex);
 }
 base.OnElementPropertyChanged(sender, e);
}

Add Export Renderer above the namespace to link dropdown view in .NetStandard project to Android Client Project. This is very important step for any custom renderer approach.
```
[assembly: ExportRenderer(typeof(Dropdown), typeof(DropdownRenderer))]
namespace XF.Ctrls.Droid
```

Full Code of Dropdown Renderer

Here, we will see the full code for Dropdown Renderer.

[assembly: ExportRenderer(typeof(Dropdown), typeof(DropdownRenderer))]
namespace XF.Ctrls.Droid
{
    public class DropdownRenderer : ViewRenderer<Dropdown, Spinner>
    {
        Spinner spinner;
        public DropdownRenderer(Context context) : base(context)
        {

        }

        protected override void OnElementChanged(ElementChangedEventArgs<Dropdown> e)
        {
            base.OnElementChanged(e);

            if (Control == null)
            {
                spinner = new Spinner(Context);
                SetNativeControl(spinner);
            }

            if (e.OldElement != null)
            {
                Control.ItemSelected -= OnItemSelected;
            }
            if (e.NewElement != null)
            {
                var view = e.NewElement;

                ArrayAdapter adapter = new ArrayAdapter(Context, Android.Resource.Layout.SimpleListItem1, view.ItemsSource);
                Control.Adapter = adapter;

                if (view.SelectedIndex != -1)
                {
                    Control.SetSelection(view.SelectedIndex);
                }

                Control.ItemSelected += OnItemSelected;
            }
        }

        protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            var view = Element;
            if (e.PropertyName == Dropdown.ItemsSourceProperty.PropertyName)
            {
                ArrayAdapter adapter = new ArrayAdapter(Context, Android.Resource.Layout.SimpleListItem1, view.ItemsSource);
                Control.Adapter = adapter;
            }
            if (e.PropertyName == Dropdown.SelectedIndexProperty.PropertyName)
            {
                Control.SetSelection(view.SelectedIndex);
            }
            base.OnElementPropertyChanged(sender, e);
        }

        private void OnItemSelected(object sender, AdapterView.ItemSelectedEventArgs e)
        {
            var view = Element;
            if (view != null)
            {
                view.SelectedIndex = e.Position;
                view.OnItemSelected(e.Position);
            }
        }
    }
}

Step 4: Implementation of Dropdown & It’s Demo for Android Platform

In this step, we will see how to use the view in Xamarin.Forms.

Open your designer file and in my case MainPage.xaml and add the control as shown below.

<local:Dropdown HorizontalOptions="FillAndExpand"
      VerticalOptions="Center"
      BackgroundColor="LawnGreen"
      x:Name="dropdown"/>

Set ItemsSource and SelectedIndex as shown in below.

dropdown.ItemsSource = Items1;
dropdown.SelectedIndex = 1;

Add item selection event to dropdown as shown in below.

public MainPage()
{
 //...
 dropdown.ItemSelected += OnDropdownSelected;
}

private void OnDropdownSelected(object sender, ItemSelectedEventArgs e)
{
 label.Text = Items1[e.SelectedIndex];
}

Full Code implementation of Dropdown in MainPage

Here, we will see the full code for Main Page.

namespace XF.Ctrls
{
    public partial class MainPage : ContentPage
    {
        List<string> Items1 = new List<string>();
        List<string> Items2 = new List<string>();
        bool IsItem1 = true;

        public MainPage()
        {
            InitializeComponent();

            for (int i = 0; i < 4; i++)
            {
                Items1.Add(i.ToString());
            }

            for (int i = 0; i < 10; i++)
            {
                Items2.Add(i.ToString());
            }

            dropdown.ItemsSource = Items1;
            dropdown.SelectedIndex = 1;
            dropdown.ItemSelected += OnDropdownSelected;
        }

        private void OnDropdownSelected(object sender, ItemSelectedEventArgs e)
        {
            label.Text = IsItem1 ? Items1[e.SelectedIndex] : Items2[e.SelectedIndex];
        }

        private void btn_Clicked(object sender, EventArgs e)
        {
            dropdown.ItemsSource = IsItem1 ? Items2 : Items1;
            dropdown.SelectedIndex = IsItem1 ? 5 : 1;
            IsItem1 = !IsItem1;
        }
    }
}

Demo

The following screens shows the output this tutorial and it is awesome to have this dropdown in Xamarin.Forms.

This article covers the implementation of new dropdown control in Android Platform alone. Currently, I am working on creating spinner like dropdown control in iOS Platform and will post the article about the implementation of the dropdown in iOS Platform soon.

My plan is to create a dropdown control for supporting all platforms and offering this control as a standard plugin.

Download Code

You can download the code from GitHub. If you have doubt, feel free to post comment. If you like this article and is useful to you, do like, share the article & star the repository on GitHub.

Introduction:

In this tutorial, we will learn how to use FlowListView in Xamarin.Forms to create GridView. FlowListView is an awesome plugin facilitates developer to achieve features like infinite loading, Item Tapped Command, Item appearing event, item disappearing event and more.

Coding Part:

Steps:

I have split this part into 3 steps as in the following.

Creating new Xamarin.Forms Projects.
Setting up the plugin for Xamarin.Forms Application.
Implementing GridView with FlowListView.

Step 1: Creating new Xamarin.Forms Projects

Create New Project by Selecting New -> Project -> Select Xamarin Cross Platform App and Click OK.

Then Select Android and iOS Platforms as shown below with Code Sharing Strategy as PCL or .Net Standard and Click OK.

Step 2: Setting up the plugin for Xamarin.Forms Application

Open Nuget Package Manager against the solution and do search for FlowListView Plugin or Paste the following Nuget package.

Install-Package DLToolkit.Forms.Controls.FlowListView -Version 2.0.11

Click Install to install this Plugin against your PCL Project or .NET standard Project.

We need to install this application in all client projects.

Step 3: Implementing GridView with FlowListView

Open “App.xaml.cs” or “App.cs” and add the following line after InitializeComponent function.
```
public App()
{
   InitializeComponent();
   FlowListView.Init();
   MainPage = new MainPage();
}
```

Open your Page for example “MainPage” and add the flowlistview reference in designer as like below.

…
xmlns:flv="clr-namespace:DLToolkit.Forms.Controls;assembly=DLToolkit.Forms.Controls.FlowListView"
…

Implement the flowlistview like below.

<flv:FlowListView FlowColumnCount="3" 
                SeparatorVisibility="Default" 
                HasUnevenRows="True"
                FlowItemTappedCommand="{Binding ItemTappedCommand}" 
                FlowItemsSource="{Binding Items}">

    <flv:FlowListView.FlowColumnTemplate>
        <DataTemplate>
            <Frame BackgroundColor="Purple"
                Margin="5">
                <Label HorizontalOptions="Fill" 
                    VerticalOptions="Fill" 
                    TextColor="White"
                    XAlign="Center"
                    YAlign="Center" 
                    Text="{Binding }"/>
            </Frame>
        </DataTemplate>
    </flv:FlowListView.FlowColumnTemplate>
</flv:FlowListView>

Then create a ViewModel for your Page and in my case I have created a class named as “MainPageModel.cs” and inherits the class with BindableObject.
```
public class MainPageModel : BindableObject
{
 …
}
```

Then add the view model to your page like below

public partial class MainPage : ContentPage
{
    MainPageModel pageModel;
    public MainPage()
    {
        InitializeComponent();
        pageModel = new MainPageModel(this);
        BindingContext = pageModel;
    }
}

Full Code:

MainPage.xaml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:flv="clr-namespace:DLToolkit.Forms.Controls;assembly=DLToolkit.Forms.Controls.FlowListView"
             x:Class="FlowListViewSample.MainPage">

    <StackLayout Padding="10">
        <flv:FlowListView FlowColumnCount="3" 
                SeparatorVisibility="Default" 
                HasUnevenRows="True"
                FlowItemTappedCommand="{Binding ItemTappedCommand}" 
                FlowItemsSource="{Binding Items}">

            <flv:FlowListView.FlowColumnTemplate>
                <DataTemplate>
                    <Frame BackgroundColor="Purple"
                Margin="5">
                        <Label HorizontalOptions="Fill" 
                    VerticalOptions="Fill" 
                    TextColor="White"
                    XAlign="Center"
                    YAlign="Center" 
                    Text="{Binding }"/>
                    </Frame>
                </DataTemplate>
            </flv:FlowListView.FlowColumnTemplate>
        </flv:FlowListView>
    </StackLayout>

</ContentPage>

MainPage.xaml.cs

using Xamarin.Forms;

namespace FlowListViewSample
{
    public partial class MainPage : ContentPage
    {
        MainPageModel pageModel;
        public MainPage()
        {
            InitializeComponent();
            pageModel = new MainPageModel(this);
            BindingContext = pageModel;
        }
    }
}

MainPageModel.cs

using System.Collections.ObjectModel;
using Xamarin.Forms;

namespace FlowListViewSample
{
    public class MainPageModel : BindableObject
    {
        private MainPage mainPage;

        public MainPageModel(MainPage mainPage)
        {
            this.mainPage = mainPage;
            AddItems();
        }

        private void AddItems()
        {
            for (int i = 0; i < 20; i++)
                Items.Add(string.Format("List Item at {0}", i));
        }

        private ObservableCollection _items = new ObservableCollection();
        public ObservableCollection Items
        {
            get
            {
                return _items;
            }
            set
            {
                if (_items != value)
                {
                    _items = value;
                    OnPropertyChanged(nameof(Items));
                }
            }
        }

        public Command ItemTappedCommand
        {
            get
            {
                return new Command((data) =>
                {
                    mainPage.DisplayAlert("FlowListView", data + "", "Ok");
                });
            }
        }
    }
}

Demo:

Reference

FlowListView for Xamarin.Forms

https://github.com/daniel-luberda/DLToolkit.Forms.Controls/tree/master/FlowListView/

Download Code

You can download the code from GitHub. If you have doubt, feel free to post comment. If you like this article and is useful to you, do like, share the article & star the repository on GitHub.

Introduction:

In this tutorial, we will learn how to use extension methods with Linq in C# to simplify the coding. Extension Methods are a new feature in C# 3.0 and is nothing but a user made pre-defined functions. An Extension Method enables us to add methods to existing types without creating a new derived type, recompiling, or modify the original types.

Extension Methods:

It enable us to add methods to existing types without creating a new derived type.
It is a static method.
It is defined in a static class.
It uses “this” keyword to apply the extension to the particular type.
We don’t want to compile the application. Visual Studio intelli-sense will find the extension method immediately.

Coding Part:

I have created a Console application by selecting File->New Project->Console Application.

Then created a Model class “Employee.cs” with member variables like below.

public class Employee
{
 public string Name { get; set; }
 public string MobileNo { get; set; }
 public string Salary { get; set; }

 public string String()
 {
  return string.Format("Name:{0} MobileNo:{1} Salary:{2}", Name, MobileNo, Salary);
 }
}

Then added values to employee list as like below

static void AddEmployees()
{
 employees.Add(new Employee() { Name = "Mushtaq", MobileNo = "9876543210", Salary = "20K" });
 employees.Add(new Employee() { Name = "Mohammed Mushtaq", MobileNo = "9876543211", Salary = "30K" });
 employees.Add(new Employee() { Name = "Mushtaq Ahmed", MobileNo = "9876543212", Salary = "20K" });
 employees.Add(new Employee() { Name = "Raj", MobileNo = "9876543213", Salary = "25K" });
}

Now we will get results from list using Linq for “FirstOrDefault”, “LastOrDefault” or “IndexOf”.

Console.WriteLine(employees.Where(x => x.Name.Contains("Mushtaq")).FirstOrDefault().String());
Console.WriteLine(employees.Where(x => x.Name.Contains("Mushtaq")).LastOrDefault().String());
Console.WriteLine(employees.IndexOf(employees.Where(x => x.Name.Contains("Mushtaq")).FirstOrDefault()));

Result:

Now I have created a static class named as “LinqExtension.cs” and created extension methods for selecting “FirstOrDefault”, “LastOrDefault” and getting index of the object from list using Linq.

public static class LinqExtension
{
 public static T WhereFirstOrDefault(this List list, Func predicate)
 {
  return list.Where(predicate).FirstOrDefault();
 }
 public static T WhereLastOrDefault(this List list, Func predicate)
 {
  return list.Where(predicate).LastOrDefault();
 }
 public static int IndexOf(this List list, Func predicate)
 {
  return list.IndexOf(list.WhereFirstOrDefault(predicate));
 }
}

The extension methods can be implemented as like the below

Console.WriteLine(employees.WhereFirstOrDefault(x => x.Name.Contains("Mushtaq")).String());
Console.WriteLine(employees.WhereLastOrDefault(x => x.Name.Contains("Mushtaq")).String());
Console.WriteLine(employees.IndexOf(x => x.Name.Contains("Mushtaq")));

Result:

The extension will return the same result. But the line of code will be less comparatively.

Full Code:

Full code implementations of extension methods.

namespace ExtensionsWithLinq
{
    class Program
    {
        static List employees = new List();
        static void Main(string[] args)
        {
            AddEmployees();

            Console.WriteLine("...Extension with Linq...");
            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine("Linq to get details of Mushtaq with Linq-FirstOrDefault");
            Console.WriteLine();
            Console.WriteLine(employees.Where(x => x.Name.Contains("Mushtaq")).FirstOrDefault().String());

            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine("Linq to get details of Mushtaq with Linq-LastOrDefault");
            Console.WriteLine();
            Console.WriteLine(employees.Where(x => x.Name.Contains("Mushtaq")).LastOrDefault().String());

            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine("Linq to get index of Mushtaq with Linq-IndexOf");
            Console.WriteLine();
            Console.WriteLine(employees.IndexOf(employees.Where(x => x.Name.Contains("Mushtaq")).FirstOrDefault()));

            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine("Linq to get details of Mushtaq with Linq-FirstOrDefault Extension");
            Console.WriteLine();
            Console.WriteLine(employees.WhereFirstOrDefault(x => x.Name.Contains("Mushtaq")).String());

            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine("Linq to get details of Mushtaq with Linq-LastOrDefault Extension");
            Console.WriteLine();
            Console.WriteLine(employees.WhereLastOrDefault(x => x.Name.Contains("Mushtaq")).String());

            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine("Linq to get index of Mushtaq with Linq-IndexOf Extension");
            Console.WriteLine();
            Console.WriteLine(employees.IndexOf(x => x.Name.Contains("Mushtaq")));

            Console.ReadLine();
        }

        static void AddEmployees()
        {
            employees.Add(new Employee() { Name = "Mushtaq", MobileNo = "9876543210", Salary = "20K" });
            employees.Add(new Employee() { Name = "Mohammed Mushtaq", MobileNo = "9876543211", Salary = "30K" });
            employees.Add(new Employee() { Name = "Mushtaq Ahmed", MobileNo = "9876543212", Salary = "20K" });
            employees.Add(new Employee() { Name = "Raj", MobileNo = "9876543213", Salary = "25K" });
        }
    }
}

Reference:

Linq	https://docs.microsoft.com/en-us/dotnet/csharp/linq/
Extensions	https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/extension-methods

Download Code

You can download the code from GitHub. If you have doubt, feel free to post comment. If you like this article and is useful to you, do like, share the article & star the repository on GitHub.

Introduction:

In this tutorial, we will learn how to use Rg.Plugin.Popup in Xamarin.Forms using Fresh MMVM. In my previous articles, we have learned how to use Fresh MVVM with Navigation Page, Master Detail Page and Tabbed Page. If you are new to Fresh MVVM, kindly read my previous articles on Fresh MVVM to know the basics & rules of Fresh MVVM.

Coding Part:

Steps:

I have split this part into 3 steps as in the following.

Creating new Xamarin.Forms Projects.
Setting up the plugin for Xamarin.Forms Application.
Implementing Fresh MVVM.

Step 1: Creating new Xamarin.Forms Projects

Create New Project by Selecting New -> Project -> Select Xamarin Cross Platform App and Click OK.

Then Select Android and iOS Platforms as shown below with Code Sharing Strategy as PCL or .Net Standard and Click OK.

Step 2: Setting up the plugin for Xamarin.Forms Application

We will start coding for Fresh MVVM. Create New Xamarin Forms Project. Open Nuget Package Manager against the solution and do search for Fresh MVVM Plugin or Paste the following Nuget Installation.

Install-Package FreshMvvm -Version 2.2.3

Click Install to install this Plugin against your PCL Project or .NET standard Project. Then download the Rg.Plugin.Popup by using the following Nuget package.

Install-Package Rg.Plugins.Popup -Version 1.1.5.188

Click Install to install this Plugin against your PCL Project or .NET standard Project and all dependent platform projects.

Step 3: Implementing Fresh MVVM Page & Page Models

Create your XAML page (view) with name ended up with “Page”.
Create PageModel by create Class name ended with “PageModel” and inherited with “FreshBasePageModel” as shown below screenshot.
I have created a Page & PageModel named as “MainPage” & “MainPageModel” and set this page as Main Page/Root Page of the application as shown in the following.

Set MainPage:

We need to set the MainPageModel as MainPage using FreshNavigationConatiner. Open App.xaml.cs or App.cs and set MainPage.
```
// To set MainPage for the Application
var page = FreshPageModelResolver.ResolvePageModel();
var basicNavContainer = new FreshNavigationContainer(page);
MainPage = basicNavContainer;
```

4. Then create a Popup Page using Rg.Plugins.Popup by adding “”. The following code snippet shows how to create popup using Rg.Plugin. I have created a Xamarin.Forms Page and named as “MyPopupPage.xaml”.

<?xml version="1.0" encoding="utf-8" ?>
<popup:PopupPage xmlns="http://xamarin.com/schemas/2014/forms"
                 xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
                 xmlns:popup="clr-namespace:Rg.Plugins.Popup.Pages;assembly=Rg.Plugins.Popup"
                 CloseWhenBackgroundIsClicked="True"
                 x:Class="Popup.MyPopupPage">
    <popup:PopupPage.Content>
        <StackLayout Padding="10"
                     BackgroundColor="White"
                     HorizontalOptions="Center"
                     VerticalOptions="Center">
            <Label Text="Fresh MVVM Rg.Plugin.Popup"
                VerticalOptions="CenterAndExpand" 
                HorizontalOptions="CenterAndExpand" />
            <Button Command="{Binding ClosePopupCommand}"
                    Text="Close Popup"/>
        </StackLayout>
    </popup:PopupPage.Content>
</popup:PopupPage>

The code behind has “PopupPage” as parent page like shown in the following code part.

public partial class MyPopupPage : PopupPage
{
 public MyPopupPage ()
 {
  InitializeComponent ();
 }
}

Then create a Page Model for the created Popup Page with Fresh MVVM rules. If you have not remember the rules or new to Fresh MVVM, Kindly refer my previous articles on fresh MVVM.
```
public class MyPopupPageModel : FreshBasePageModel
{

}
```
Rg Popup Page has a separate Navigation Stack. So, open and close the popup, we need to have separate Navigation Stack. To know more about Rg.Plugin.Popup, refer the GitHub Link.
Rg.Plugin.Popup Link: https://github.com/rotorgames/Rg.Plugins.Popup
Then include Fresh MVVM extension/Utility class to your Xamarin Shared Project. This extension file is created & open sourced by the author “Libin Joseph”. You can download this file from the following GitHub Link.
Fresh MVVM Extension Link: https://github.com/libin85/FreshMvvm.Popup
To open popup page like navigating to normal Fresh MVVM page, use the following code snippet.
```
return new Command(async () =>
{
        await CoreMethods.PushPopupPageModel();
});
```
To close the popup page like closing normal Fresh MVVM page, use the following code snippet.
```
return new Command(async () =>
{
        await CoreMethods.PopPopupPageModel();
});
```

Demo:

The below screenshots for your reference.

Main Page	Rg Popup Page

Reference:

Fresh MVVM	https://github.com/rid00z/FreshMvvm
Rg.Plugin.Popup	https://github.com/rotorgames/Rg.Plugins.Popup
Fresh MVVM Popup Extension	https://github.com/libin85/FreshMvvm.Popup/

Download Code

You can download the code from GitHub. If you have doubt, feel free to post comment. If you like this article and is useful to you, do like, share the article & star the repository on GitHub.

Introduction:

In this tutorial, we will learn how to use master detail page using Fresh MVVM with FreshNavigationContainer. It has some work around for creating master detail page more than creating master detail page using FreshMasterContainer. In my previous tutorials, we have learned the method to create master detail page using Fresh Master Container. To know more, visit my previous article.

Kindly refer my previous article on Fresh MVVM to know the basics & rules of Fresh MVVM.

Coding Part:

Steps:

I have split this part into 3 steps as in the following.

Creating new Xamarin.Forms Projects.
Setting up the plugin for Xamarin.Forms Application.
Implementing Fresh MVVM.

Step 1: Creating new Xamarin.Forms Projects

Create New Project by Selecting New -> Project -> Select Xamarin Cross Platform App and Click OK.

Then Select Android and iOS Platforms as shown below with Code Sharing Strategy as PCL or .Net Standard and Click OK.

Step 2: Setting up the plugin for Xamarin.Forms Application

We will start coding for Fresh MVVM. Create New Xamarin Forms Project. Open Nuget Package Manager against the solution and do search for Fresh MVVM Plugin or Paste the following Nuget Installation.

Install-Package FreshMvvm -Version 2.2.3

Click Install to install this Plugin against your PCL Project or .NET standard Project.

Step 3: Implementing Fresh MVVM.

Create your XAML page (view) with name ended up with “Page”.
Create PageModel by create Class name ended with “PageModel” and inherited with “FreshBasePageModel” as shown below screenshot.

In the same way, I have created pages “MyMasterDetailPage”, “MasterPage”, “Detail1Page” and “Detail2Page” with two respective models “MyMasterDetailPageModel”, “MasterPageModel”, “Detail1PageModel” and “Detail2PageModel”.

Here,

MyMasterDetailPage	container to have both Master & Detail page
MasterPage	Master or Menu Page
Detail1Page, Detail2Page	Detail pages of the Master detail page

Set MainPage:

We need to set the MainPageModel as MainPage using FreshNavigationConatiner.

Open App.xaml.cs or App.cs and set MainPage.

// To set MainPage for the Application
var page = FreshPageModelResolver.ResolvePageModel();
var basicNavContainer = new FreshNavigationContainer(page);
MainPage = basicNavContainer;

Then add button with command for opening the MasterDetailPage from MainPage.

public Command GotoSecondPageCommand
{
    get
    {
        return new Command(async () =>
        {
            await CoreMethods.PushPageModel();
        });
    }
}

Open MyMasterDetailPage and add Master, Detail page to the constructor of the page like below.

public MyMasterDetailPage()
{
    InitializeComponent();

    NavigationPage.SetHasNavigationBar(this, false);

    Master = FreshPageModelResolver.ResolvePageModel();
    Detail = new NavigationPage(FreshPageModelResolver.ResolvePageModel());
}

Then click “Run” to see your Custom Master Detail Page using FreshMVVM with FreshNavigationContainer.

By this way, we can have Navigation Service & Stack for all type of Pages. Kindly find the screenshot for your reference.

MainPage	Master Page(Detail)	Master Page(Master)

Download Code

You can download the code from GitHub. If you have doubt, feel free to post comment. If you like this article and is useful to you, do like, share the article & star the repository on GitHub.

Introduction:

In this article, we will learn how to convert any web url to pdf file in Android. To create PDF in Android, we will use iText Library. But here, we will not use any third party libraries like iText Library.

iText Library:

This library is awesome and very useful. But the iText Community licensed this library with AGPL license. So, we need to license our own application under AGPL license.

Reference Link: http://developers.itextpdf.com/

But google provided print API for Android to print any content directly from mobile app. We can use same Print API for generating and saving the pdf file. Without any introduction, we will skip into the coding part.

Reference Link: https://developer.android.com/training/printing/

Coding Part

I have detailed the article in the following sections.

Creating a new project with Empty activity.
Setting up the project with Print Adapter Extension.
Implementation of URL to PDF file generation.

Step 1: Creating New Project with Empty Activity.

Creating New Project with Android Studio Open Android Studio and Select Create new project.
Name the project as your wish and select your activity template.
Click “finish” button to create new project in Android Studio.

Step 2: Setting up the project with Print Adapter Extension

To create pdf file, we need to use “PrintDocumentAdapter.LayoutResultCallback” and it cannot be used by any class.
So, we need to create a class with package name as “android.print” and we will named the class as “PdfPrint.java”

Then paste the following code with callback interface.

@SuppressWarnings("ALL")
public class PdfPrint {
    private static final String TAG = PdfPrint.class.getSimpleName();
    private final PrintAttributes printAttributes;

    public PdfPrint(PrintAttributes printAttributes) {
        this.printAttributes = printAttributes;
    }

    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    public void print(final PrintDocumentAdapter printAdapter, final File path, final String fileName,
                      final CallbackPrint callback) {
        printAdapter.onLayout(null, printAttributes, null,
                new PrintDocumentAdapter.LayoutResultCallback() {
                    @Override
                    public void onLayoutFinished(PrintDocumentInfo info, boolean changed) {
                        printAdapter.onWrite(new PageRange[]{PageRange.ALL_PAGES}, getOutputFile(path, fileName),
                                new CancellationSignal(), new PrintDocumentAdapter.WriteResultCallback() {
                                    @Override
                                    public void onWriteFinished(PageRange[] pages) {
                                        super.onWriteFinished(pages);
                                        if (pages.length > 0) {
                                            File file = new File(path, fileName);
                                            String path = file.getAbsolutePath();
                                            callback.onSuccess(path);
                                        } else {
                                            callback.onFailure(new Exception("Pages length not found"));
                                        }

                                    }
                                });
                    }
                }, null);
    }

    private ParcelFileDescriptor getOutputFile(File path, String fileName) {
        if (!path.exists()) {
            path.mkdirs();
        }
        File file = new File(path, fileName);
        try {
            file.createNewFile();
            return ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_WRITE);
        } catch (Exception e) {
            Log.e(TAG, "Failed to open ParcelFileDescriptor", e);
        }
        return null;
    }
    public interface CallbackPrint {
        void onSuccess(String path);
        void onFailure(Exception ex);
    }
}

Step 3: Implementation of URL to PDF file generation

In this part, we will learn how to use the Printer Extension created in the last step and How to create a PDF file.

Open your activity_main.xml file and Paste the following code.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.androimads.androidpdfmaker.MainActivity">

    <WebView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/webView"
        android:layout_above="@id/textView"/>

    <TextView
        android:visibility="gone"
        android:background="@color/colorBackground"
        android:padding="2dp"
        android:text="Saving..."
        android:gravity="center"
        android:textColor="#FFFFFF"
        android:layout_alignParentBottom="true"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/textView"/>

</RelativeLayout>

Then open your Activity file, in my case “MainActivity.java” and initialize “WebView” as shown below

webView = findViewById(R.id.webView);
webView.loadUrl("https://www.androidmads.info/");
webView.setWebViewClient(new WebViewClient());

Then create a pdf print adapter with print attributes what we need

String fileName = String.format("%s.pdf", new SimpleDateFormat("dd_MM_yyyyHH_mm_ss", Locale.US).format(new Date()));
final PrintDocumentAdapter printAdapter = webView.createPrintDocumentAdapter(fileName);
PrintAttributes printAttributes = new PrintAttributes.Builder()
  .setMediaSize(PrintAttributes.MediaSize.ISO_A4)
  .setResolution(new PrintAttributes.Resolution("pdf", "pdf", 600, 600))
  .setMinMargins(PrintAttributes.Margins.NO_MARGINS)
  .build();

Here, I have used default page size as “A4”. You can change as per your need.

Then call your extension method with Callback as shown below

new PdfPrint(printAttributes).print(
 printAdapter,
 file,
 fileName,
 new PdfPrint.CallbackPrint() {
  @Override
  public void onSuccess(String path) {

  }

  @Override
  public void onFailure(Exception ex) {
  }
 });

The PdfPrint.Callback will return success or failure based on the extension method we created.

Full code of MainActivity:

Here you can find the full code of the MainActivity.java for generating pdf file.

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
public class MainActivity extends AppCompatActivity {

    private WebView webView;
    private TextView textView;
    private int PERMISSION_REQUEST = 0;
    private boolean allowSave = true;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textView = findViewById(R.id.textView);
        webView = findViewById(R.id.webView);
        webView.loadUrl("https://www.androidmads.info/");
        webView.setWebViewClient(new WebViewClient());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (item.getItemId() == R.id.save) {
            savePdf();
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    private void savePdf() {
        if(!allowSave)
            return;
        allowSave = false;
        textView.setVisibility(View.VISIBLE);
        if (ActivityCompat.checkSelfPermission(getApplicationContext(), Manifest.permission.WRITE_EXTERNAL_STORAGE)
                == PERMISSION_GRANTED) {
            String fileName = String.format("%s.pdf", new SimpleDateFormat("dd_MM_yyyyHH_mm_ss", Locale.US).format(new Date()));
            final PrintDocumentAdapter printAdapter = webView.createPrintDocumentAdapter(fileName);
            PrintAttributes printAttributes = new PrintAttributes.Builder()
                    .setMediaSize(PrintAttributes.MediaSize.ISO_A4)
                    .setResolution(new PrintAttributes.Resolution("pdf", "pdf", 600, 600))
                    .setMinMargins(PrintAttributes.Margins.NO_MARGINS)
                    .build();
            final File file = Environment.getExternalStorageDirectory();
            new PdfPrint(printAttributes).print(
                    printAdapter,
                    file,
                    fileName,
                    new PdfPrint.CallbackPrint() {
                        @Override
                        public void onSuccess(String path) {
                            textView.setVisibility(View.GONE);
                            allowSave = true;
                            Toast.makeText(getApplicationContext(),
                                    String.format("Your file is saved in %s", path),
                                    Toast.LENGTH_LONG).show();
                        }

                        @Override
                        public void onFailure(Exception ex) {
                            textView.setVisibility(View.GONE);
                            allowSave = true;
                            Toast.makeText(getApplicationContext(),
                                    String.format("Exception while saving the file and the exception is %s", ex.getMessage()),
                                    Toast.LENGTH_LONG).show();
                        }
                    });
        } else {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, PERMISSION_REQUEST);
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == PERMISSION_REQUEST) {
            if (grantResults[Arrays.asList(permissions).indexOf(Manifest.permission.WRITE_EXTERNAL_STORAGE)] == PERMISSION_GRANTED) {
                savePdf();
            }
        }
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }
}

Download Code

You can download the full source code of the article in GitHub. If you like this article, do star the repo in GitHub. Hit like the article.

Introduction:

In this tutorial, we will learn how create Tabbed Page in Xamarin.Forms using Fresh MVVM. We already learned how to create your master details page in my previous tutorials. If you are new to Fresh MVVM, You can read my previous article here.

Articles of FreshMVVM:

Coding Part:

Steps:

I have split this part into 3 steps as in the following.

Creating new Xamarin.Forms Projects.
Setting up the plugin for Xamarin.Forms Application.
Implementing Fresh MVVM Tabbed Page.

Step 1: Creating new Xamarin.Forms Projects

Create New Project by Selecting New -> Project -> Select Xamarin Cross Platform App and Click OK.

Then Select Android and iOS Platforms as shown below with Code Sharing Strategy as PCL or .Net Standard and Click OK.

Step 2: Setting up the plugin for Xamarin.Forms Application

We will start coding for Fresh MVVM. Create New Xamarin Forms Project. Open Nuget Package Manager against the solution and do search for Fresh MVVM Plugin or Paste the following Nuget Installation.

Install-Package FreshMvvm -Version 2.2.3

Click Install to install this Plugin against your PCL Project or .NET standard Project.

Step 3: Implementing Fresh MVVM Tabbed Page

Create your XAML page (view) with name ended up with “Page”.
Create PageModel by create Class name ended with “PageModel” and inherited with “FreshBasePageModel” as shown below screenshot.
In the same way, I have created two pages “Detail1Page” and “Detail2Page” with two respective page models “Detail1PageModel” and “Detail2PageModel”.

Set MainPage:

To create Fresh MVVM Tabbed Page as MainPage, we should use Fresh Tabbed Navigation Container with the following code. Open App.xaml.cs or App.cs and set MainPage.

var tabbedNavigation = new FreshTabbedNavigationContainer();
tabbedNavigation.AddTab("First Tab", null);
tabbedNavigation.AddTab("Second Tab", null);
MainPage = tabbedNavigation;

Then Click Run, your Tabbed Page will be look like as on the below screenshot.
Here, we will not discuss about navigation between pages. If you want to know, you can see my previous article on Fresh MVVM.

Full Code for App.xaml.cs:

You can find the code for App.xaml.cs below

public partial class App : Application
{
    public App()
    {
        try
        {
            InitializeComponent();
            var tabbedNavigation = new FreshTabbedNavigationContainer();
           tabbedNavigation.AddTab("First Tab", null);
           tabbedNavigation.AddTab("Second Tab", null);
           MainPage = tabbedNavigation;
        }
        catch (Exception ex)
        {

        }
    }

    protected override void OnStart()
    {
        // Handle when your app starts
    }

    protected override void OnSleep()
    {
        // Handle when your app sleeps
    }

    protected override void OnResume()
    {
        // Handle when your app resumes
    }
}

Download Code

You can download the code from GitHub. If you have doubt, feel free to post comment. If you like this article and is useful to you, do like, share the article & star the repository on GitHub.

Introduction:

In this tutorial, we will learn how to perform MVVM approach in Xamarin.Forms using Fresh MVVM. MVVM approach is the best approach for Xamarin.Forms and WPF Applications. There are a lot of MVVM plugins or libraries like FreshMVVM, MVVMCross, Prism, etc. available to simplify MVVM implementations.

FreshMVVM:

FreshMVVM is designed to perform MVVM easy and simple with Xamarin.Forms Application. It is created Michael Ridland. It has certain rules to perform MVVM Databinding. You can find the plugin from GitHub and Nuget.

Kindly refer my previous article on Fresh MVVM to know the basics & rules of Fresh MVVM.

Coding Part:

Steps:

I have split this part into 3 steps as in the following.

Creating new Xamarin.Forms Projects.
Setting up the plugin for Xamarin.Forms Application.
Implementing Fresh MVVM.

Step 1: Creating new Xamarin.Forms Projects

Create New Project by Selecting New -> Project -> Select Xamarin Cross Platform App and Click OK.

Then Select Android and iOS Platforms as shown below with Code Sharing Strategy as PCL or .Net Standard and Click OK.

Step 2: Setting up the plugin for Xamarin.Forms Application

We will start coding for Fresh MVVM. Create New Xamarin Forms Project. Open Nuget Package Manager against the solution and do search for Fresh MVVM Plugin or Paste the following Nuget Installation.

Install-Package FreshMvvm -Version 2.2.3

Click Install to install this Plugin against your PCL Project or .NET standard Project.

Step 3: Implementing Fresh MVVM.

Create your XAML page (view) with name ended up with “Page”.
Create PageModel by create Class name ended with “PageModel” and inherited with “FreshBasePageModel” as shown below screenshot.
In the same way, I have created two pages “Detail1Page” and “Detail2Page” with two respective page models “Detail1PageModel” and “Detail2PageModel”.

Set MainPage:

To create Fresh MVVM Master Detail Page as MainPage, we should use Fresh Master Detail Navigation Container with the following code. Open App.xaml.cs or App.cs and set MainPage.

var masterNavigation = new FreshMasterDetailNavigationContainer();
masterNavigation.Init("Menu");
masterNavigation.AddPage("First Page", null);
masterNavigation.AddPage("Second Page", null);
MainPage = masterNavigation;

Here, we will not discuss about navigation between pages. If you want to know, you can see my previous article on Fresh MVVM.

Full Code for App.xaml.cs:

You can find the code for App.xaml.cs below

public partial class App : Application
{
    public App()
    {
        try
        {
            InitializeComponent();
            var masterNavigation = new FreshMasterDetailNavigationContainer();
            masterNavigation.Init("Menu");
            masterNavigation.AddPage("First Page", null);
            masterNavigation.AddPage("Second Page", null);
            MainPage = masterNavigation;
        }
        catch (Exception ex)
        {

        }
    }

    protected override void OnStart()
    {
        // Handle when your app starts
    }

    protected override void OnSleep()
    {
        // Handle when your app sleeps
    }

    protected override void OnResume()
    {
        // Handle when your app resumes
    }
}

Download Code

You can download the code from GitHub. If you have doubt, feel free to post comment. If you like this article and is useful to you, do like, share the article & star the repository on GitHub.

Introduction:

FreshMVVM:

Rules for FreshMVVM:

It has simple rules to do MVVM. It is the first and important rule. – The Views (Pages) name should be ended with Page. – The ViewModel name should be ended with PageModel. – The namespace of both Page and Pagemodel should be name. – You don’t need to set BindingContext manually. The plugin will detect the View and ViewModel with its name. We will start coding with Fresh MVVM.

Coding Part:

Steps:

I have split this part into 3 steps as in the following.

Creating new Xamarin.Forms Projects.
Setting up the plugin for Xamarin.Forms Application.
Implementing Fresh MVVM.

Step 1: Creating new Xamarin.Forms Projects

Create New Project by Selecting New -> Project -> Select Xamarin Cross Platform App and Click OK.

Then Select Android and iOS Platforms as shown below with Code Sharing Strategy as PCL or .Net Standard and Click OK.

Step 2: Setting up the plugin for Xamarin.Forms Application

We will start coding for Fresh MVVM. Create New Xamarin Forms Project. Open Nuget Package Manager against the solution and do search for Fresh MVVM Plugin or Paste the following Nuget Installation.

Install-Package FreshMvvm -Version 2.2.3

Click Install to install this Plugin against your PCL Project or .NET standard Project.

Step 3: Implementing Fresh MVVM.

Create your XAML page (view) with name ended up with “Page”.
Create PageModel by create Class name ended with “PageModel” and inherited with “FreshBasePageModel” as shown below screenshot.
The namespace of Page and PageModel should be same as shown in the above screenshots. – The Binding Properties and Command Properties are implemented same as like normal MVVM approach. – To indicate the binding properties changed by using RaisePropertyChanged instead of OnPropertyChanged event in Normal MVVM. – The following code is used to raise the property changed.
```
RaisePropertyChanged("MainPageLabel");
```

Set MainPage:

To initialize the FreshMVVM Navigation you should set the MainPage with FreshMVVM Navigation Container with the following code. Open App.xaml.cs or App.cs and set MainPage.

var page = FreshPageModelResolver.ResolvePageModel<MainPageModel>();
var basicNavContainer = new FreshNavigationContainer(page);
MainPage = basicNavContainer;

Navigation between Pages:

FreshMVVM itself has Navigation methods to make navigation between the pages.

Use PushPageModel for pushing the page in the navigation stack or goto next page instead of PushAsync in normal MVVM.
```
await CoreMethods.PushPageModel();
```
It is equivalent to the following
```
Navigation.PushAsync(new SecondPage());
```
Use PopPageModel for popping the page from navigation stack instead of PopAsync in normal MVVM.
```
await CoreMethods.PopPageModel();
```
It is equivalent to the following
```
Navigation.PopAsync();
```
Use PopToRoot to navigate from any page to root page instead of PopToAsync in normal MVVM.
```
await CoreMethods.PopToRoot(animate:false);
```
It is equivalent to the following
```
Navigation.PopToRootAsync();
```

Full Code for MainPageModel:

You can find the code for MainPageModel below

namespace FreshMVVMSample
{
    public class MainPageModel : FreshBasePageModel
    {

        #region Default Override functions
        public override void Init(object initData)
        {
            base.Init(initData);
            MainPageLabel = "Welcome to Fresh Mvvm Tutorial!";
        }

        public override void ReverseInit(object returnedData)
        {
            base.ReverseInit(returnedData);
        }

        protected override void ViewIsAppearing(object sender, EventArgs e)
        {
            base.ViewIsAppearing(sender, e);
        }

        protected override void ViewIsDisappearing(object sender, EventArgs e)
        {
            base.ViewIsDisappearing(sender, e);
        }
        #endregion

        #region Commands
        public Command GotoSecondPageCommand
        {
            get
            {
                return new Command(async () =>
                {
                    await CoreMethods.PushPageModel<SecondPageModel>();
                });
            }
        }
        #endregion

        #region Properties
        string _mainPageLabel = string.Empty;
        public string MainPageLabel
        {
            get
            {
                return _mainPageLabel;
            }
            set
            {
                if (_mainPageLabel != value)
                {
                    _mainPageLabel = value;
                    RaisePropertyChanged(nameof(MainPageLabel));
                }
            }
        }
        #endregion

    }
}

Download Code

You can download the code from GitHub. If you have doubt, feel free to post comment. If you like this article and is useful to you, do like, share the article & star the repository on GitHub.

Mobile App Development Guide

Introduction

Dropdown in Xamarin.Forms

Reference

Coding Part:

Steps:

Step 1: Creating new Xamarin.Forms Projects

Step 2: Creating a Dropdown view in Xamarin.Forms .NetStandard Project

Full Code of Dropdown View

Step 3: Wrapping Spinner for Dropdown control in Android Project.

Full Code of Dropdown Renderer

Step 4: Implementation of Dropdown & It’s Demo for Android Platform

Full Code implementation of Dropdown in MainPage

Demo

Download Code

Introduction:

Coding Part:

Steps:

Step 1: Creating new Xamarin.Forms Projects

Step 2: Setting up the plugin for Xamarin.Forms Application

Step 3: Implementing GridView with FlowListView

Full Code:

Demo:

Reference

Download Code

Introduction:

Extension Methods:

Coding Part:

Full Code:

Reference:

Download Code

Introduction:

Coding Part:

Steps:

Step 1: Creating new Xamarin.Forms Projects

Step 2: Setting up the plugin for Xamarin.Forms Application

Step 3: Implementing Fresh MVVM Page & Page Models

Set MainPage:

Demo:

Reference:

Download Code

Introduction:

Coding Part:

Steps:

Step 1: Creating new Xamarin.Forms Projects

Step 2: Setting up the plugin for Xamarin.Forms Application

Step 3: Implementing Fresh MVVM.

Set MainPage:

Download Code

Introduction:

iText Library:

Coding Part

Step 1: Creating New Project with Empty Activity.

Step 2: Setting up the project with Print Adapter Extension

Step 3: Implementation of URL to PDF file generation

Full code of MainActivity:

Download Code

Introduction:

Articles of FreshMVVM:

Coding Part:

Steps:

Step 1: Creating new Xamarin.Forms Projects

Step 2: Setting up the plugin for Xamarin.Forms Application

Step 3: Implementing Fresh MVVM Tabbed Page

Set MainPage:

Full Code for App.xaml.cs:

Download Code

Introduction:

FreshMVVM:

Coding Part:

Steps:

Step 1: Creating new Xamarin.Forms Projects

Step 2: Setting up the plugin for Xamarin.Forms Application

Step 3: Implementing Fresh MVVM.

Set MainPage:

Full Code for App.xaml.cs:

Download Code

Introduction:

FreshMVVM:

Rules for FreshMVVM: