Monthly Archives: July 2018

XFHACKS-006 Password Entry with show/hide Text feature!

Ever wished if your Xamarin.Forms Password Entry control had the option to reveal, or show the Password text that the User types on demand, instead of the black dots? 😉  Even better, without any Custom Renderers or Platform Specific code? Welcome to another lightening short post of me hacking around Xamarin.Forms elements!

So in Xamarin.Forms to enable this feature usually you need to resort to creating Custom Renderers or some platform specific implementation, which is a tedious process and a complicated implementation. So I thought of making use of my own crazy imagination and hack my way around to get this to work right from Xamarin.Forms itself!

No custom renderers, no platform specific code and no third party libraries! Just by using pure out of the box Xamarin.Forms! 😉

Sneak Peak!

That’s what we gonna be build yol!

XFHACKS Recipe!

Let the recipe begin! So basically the idea here is to have two Entry elements which represents the Entry with IsPassword enabled and another Entry with IsPassword disabled, laid on top of each other inside a Grid layout. Also we’re going to switch the visibility of these two Entry controls on a Button click event which will also be laid on top of both the Entry elements, aligned to the right most corner of the whole Grid layout. Just to add some cheery to the icing, let’s have a Button with an Icon Image inside of it, which implementation I’ll be extracting from one of my previous XFHACKS articles, XFHACKS-005 Button with full control on Text and Icon! ! Give it a read if you’re curious! 😉

Since we’re maintaining two Entry elements, we need to make sure both of them have the same Text value at any point of the user’s interaction. So to make this happen we’re going use Element to Element binding in Xamarin.Forms, where as we are binding the Text field properties of both Entry controls to eachother. Thereby one Entry’s Text changes immediately reflects on the other one and so on.

Just to show some love for my architectural practices, I’m going to move the whole Button click event and the handling of the behavior logic of this control into a TriggerAction, aha! separation of concern or loosely coupled and no direct code behind dependency allowing for more re-usability! 😀

Code!

Behold the golden XAML code!

<Grid
   Grid.Row="1"
   Grid.Column="0"
   HeightRequest="45"
   HorizontalOptions="FillAndExpand"
   IsClippedToBounds="True">

   <!--  Entry Password  -->
   <Entry
      x:Name="EntryPassword"
      Grid.Row="0"
      Grid.Column="0"
      FontSize="Medium"
      IsPassword="True"
      IsVisible="True"
      Keyboard="Plain"
      Placeholder="Password"
      Text="{Binding Source={x:Reference EntryText}, Path=Text, Mode=TwoWay}" />

   <!--  Entry Text  -->
   <Entry
      x:Name="EntryText"
      Grid.Row="0"
      Grid.Column="0"
      FontSize="Medium"
      IsPassword="False"
      IsVisible="False"
      Keyboard="Plain"
      Placeholder="Password"
      Text="{Binding Source={x:Reference EntryPassword}, Path=Text, Mode=TwoWay}" />

   <!--  Button with Icon  -->
   <Grid
      Grid.Row="0"
      Grid.Column="0"
      Padding="0,0,3,0"
      HeightRequest="27"
      HorizontalOptions="End"
      IsClippedToBounds="True"
      VerticalOptions="Center"
      WidthRequest="35">

      <!--  Button Control  -->
      <Button x:Name="ShowPasswordButton" BackgroundColor="White">
         <Button.Margin>
            <OnPlatform x:TypeArguments="Thickness">
               <On Platform="Android" Value="-4,-6,-4,-6" />
               <On Platform="iOS" Value="0" />
            </OnPlatform>
         </Button.Margin>
         <Button.Triggers>
            <EventTrigger Event="Clicked">
               <triggers:ShowPasswordTriggerAction
                  EntryPasswordName="EntryPassword"
                  EntryTextName="EntryText"
                  IconImageName="ShowPasswordButtonIcon" />
            </EventTrigger>
         </Button.Triggers>
      </Button>

      <!--  Icon Image  -->
      <Image
         x:Name="ShowPasswordButtonIcon"
         HeightRequest="25"
         HorizontalOptions="Fill"
         InputTransparent="True"
         Source="{extensions:ImageResource XFHacks.Resources.showpasswordicon.png}"
         VerticalOptions="Fill"
         WidthRequest="25" />
   </Grid>

</Grid>

 

Here we go, explanation time! So the two Entry elements are laying on top of each other and bound to each other’s Text properties, while having one Entry as IsPassword=true and the other opposite. I have given names for the Elements because we need references of them to handle the behaviour inside our TriggerAction which I will show next.

Then the Button with the Icon Image Element is aligned to the very right corner of Parent layout, laying on top of both Entry elements. I have added some padding to it to avoid it conflicting with the border of the Entry in iOS and UWP, then for Android it shouldn’t really matter visually. There’s a HeightRequest=”27″ and WidthRequest=”35″ given to this Element group because I needed to have some horizontal space besides the Image icon visually. For the Image we’re using a EmbeddedResource type image, which makes things really easy for managing the Images.

Then for the Parent Grid Layout that holds all of these Elements together,is using IsClippedToBounds property to make sure everything holds inside the Bounds of the Grid as a single UI Element.

This is the most crucial part where inside the Button click event we’re invoking a TrigerAction called ShowPasswordTriggerAction which handles all the logic and behaviour of this custom control. And we’re passing in the names of the Elements we have assigned, into the Trigger so that we can look it up inside the TriggerAction, retrieve their runtime references and handle the behavior as we need. Pretty straightforward implementation there 😉

Next let’s look into the golden TriggerAction!

/// <summary>
/// The Trigger Action that will handle
/// the Show/Hide Passeword text
/// </summary>
public class ShowPasswordTriggerAction : TriggerAction<Button>
{
    public string IconImageName { get; set; }

    public string EntryPasswordName { get; set; }

    public string EntryTextName { get; set; }

    protected override void Invoke(Button sender)
    {
        // get the runtime references 
        // for our Elements from our custom control
        var imageIconView = ((Grid) sender.Parent)
                  .FindByName<Image>(IconImageName);
        var entryPasswordView = ((Grid) ((Grid) sender.Parent).Parent).FindByName<Entry>(EntryPasswordName);
        var entryTextView = ((Grid)((Grid)sender.Parent).Parent).FindByName<Entry>(EntryTextName);

        // Switch visibility of Password 
        // Entry field and Text Entry fields
        entryPasswordView.IsVisible =     
                       !entryPasswordView.IsVisible;
        entryTextView.IsVisible = 
                       !entryTextView.IsVisible;

        // update the Show/Hide button Icon states 
        if (entryPasswordView.IsVisible)
        {
            // Password is not Visible state
            imageIconView.Source = ImageSource.FromResource(
                "XFHacks.Resources.showpasswordicon.png",
                Assembly.GetExecutingAssembly());

            // Setting up Entry curser focus
            entryPasswordView.Focus();
            entryPasswordView.Text = entryTextView.Text;
        }
        else
        {
            // Password is Visible state
            imageIconView.Source = ImageSource.FromResource(
                "XFHacks.Resources.hidepasswordicon.png",
                Assembly.GetExecutingAssembly());

            // Setting up Entry curser focus
            entryTextView.Focus();
            entryTextView.Text = entryPasswordView.Text;
        }
    }
}

 

Here’s the most important bit where we’re handling the behaviour logic of our awesome Password Entry Control! At the moment of Invoking the Button click we’re doing a simple FindByName<T> look up for our required Elements, that are the EntryPassword field, EntryText field, and the IconImage.

First of all we’re setting the visibility of the two Entry Elements opposite for each other, as in if the User clicks on Show Password state, then the Entry with Text property will be displayed, and the user clicks on Hide Password state then the Entry with Password property (black dots) will be displayed.

Then based on the state, we’re updating the button icon’s Image source, as you can see we’re setting the showpasswordicon.png and hidepasswordicon.png respectively depending on the current state.

Finally we’re doing something extra to make sure whatever the visible the Entry element is still on Focus after the switching of the Password visibility state.

There we go, pretty straight forward yeah!

 Important: You could also move that whole piece of XAML to a separate XAML file, so that you could set it up as a reusable Control in your project! 😉

Fire it up!

Alright let’s see this in action!

 

There you have it running on Android, iOS and UWP like a charm! 😀

NO CUSTOM RENDERERS! NO NATIVE CODE! MORE AWESOME! xD

Grab it on Github!

https://github.com/UdaraAlwis/XFHacks

Well then, that’s it for now. More awesome stuff on the way!

Cheers! 😀 share the love!

Improvement suggestion: I was discussing this with one of my colleagues and he pointed out an awesome tweak for a much better improvement, that is to use the same implementation with trigger and all but with a single Entry element with the IsPassword true and false state on demand instead of using two Entry elements. This is a great idea yet so simple, which will drastically improve the rendering performance. So if you wanna give it a crack please go ahead! And here’s a shout out to an awesome developer Akshay Kulkarni – ak47akshaykulkarnimake sure to check out his Github repo! 😉

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XFHACKS-005 Button with full control on Text and Icon!

Ever came across an instance where you wished if you had more control or customization over the Text and Icon properties of your Xamarin.Forms Button? even better even without any Custom Renderers or Platform Specific code? Welcome to another lightening short post of me hacking around Xamarin.Forms elements!

Uh oh, in Xamarin.Forms?!

The default Xamarin.Forms Button has it’s own limitations for customisation, specially in the Text and Icon, there’s not much control over those properties in terms of,

  • Alignment of Text and Icon
  • Positioning of Text and Icon 
  • Default upper case Text in Android
  • Icon Image Size and Aspect Property
  • Icon Source only limited for Local Images

Talking of the Icon Source, you can only use Platform Specific Local Images for it, you cannot use Embedded Resources for it.

So I thought of making use of my own crazy imagination and hack my way around to fix all those limitations!

No custom renderers, no platform specific code and no third party libraries! Just by using pure out of the box Xamarin.Forms! 😉

Usual approach…

Now as an out of the box solution for this we could avoid using Xamarin.Forms Button totally and switch to a Xamarin.Forms Label or Image control with a Tap gesture recognizer attached to it. But then it wouldn’t actually give that nice look and feel of a button does it, specially in Android that nice ripple effects and on iOS the fade out effect on the button click is something really nice to have on your UI.

So… wait for it….

XFHACKS Receipe!

Here’s my awesome solution, we’re still going to stick to Xamarin.Forms Button button, and we’ll be laying down a Label or an Image on top of our Button view inside a Grid layout. This is actually very common hack of mine if you had gone through previous XFHACKS articles of my blog.

Yep sounds super simple, yet solves all of the issues I just mentioned above. Basically we’re constructing our own Custom Button control right from Xamarin.Forms elements, properties and behaviours without any custom renderers or platform code.

So getting into more details, here’s how we’re going to solve the above talked issues. For Alignment of the Text and Icon in the button, we are going to use the HorizontalOption of both Image and Label element that we’re placing on top of the Button. Then the Position of those elements, we shall resort to the Margin property of each. Since we’re using the Image control itself the Source property issue is automatically solved. Then as an added advantage you could also have the control over the Aspect property of the Image Icon you want to display in your button.

Now on top of all that one might wonder when you place a Label or Image on top of a Button, wouldn’t it obstruct the Clickable touch area of the Button? That’s where InputTransparent comes into rescue, passing down the touch even down to the Button straight away!

To add some cherry on top of the icing, we’re going to use the IsClippedToBounds property to crop out any areas of the inner elements of the Grid being rendered outside the View bounds of the Grid itself, so everything comes together as a single Element on UI.

Now all these comes together solving the issues that I have pointed out at the beginning! 😉

Sneak Peak!

That’s what we gonna be build yol!

Code and Run!

Behold the golden XAML code!

<!--  Button with Text and Icon  -->
<Grid
    Grid.Row="1"
    Grid.Column="0"
    HeightRequest="40"
    HorizontalOptions="Fill"
    IsClippedToBounds="True"
    VerticalOptions="Center">

    <!--  Button Control  -->
    <Button BackgroundColor="#2196F3">
        <Button.Margin>
            <OnPlatform x:TypeArguments="Thickness">
                <On Platform="Android" Value="-4,-6,-4,-5" />
                <On Platform="iOS" Value="0" />
            </OnPlatform>
        </Button.Margin>
    </Button>

    <!--  Text Label  -->
    <Label
        Margin="10,0,0,0"
        FontAttributes="Bold"
        FontSize="Small"
        HorizontalOptions="Start"
        HorizontalTextAlignment="Center"
        InputTransparent="True"
        Text="go next"
        TextColor="White"
        VerticalOptions="Center"
        VerticalTextAlignment="Center" />

    <!--  Icon Image  -->
    <Image
        Margin="0,0,5,0"
        HeightRequest="30"
        HorizontalOptions="End"
        InputTransparent="True"
        Source="{extensions:ImageResource XFHacks.Resources.rightarrowicon.png}"
        VerticalOptions="Center"
        WidthRequest="30" />
</Grid>

 

There you have it as we discussed earlier, our empty Button and on top of that the Label and the Image elements inside a Grid. As you can see the Button has some Margin value added for Android run time of, “-4,-6,-4,-5” which is to get rid of the default empty space that’s rendered around the Button at Android run time. The button will be spread across the whole Grid in background with its default HorizontalOptions=”Fill” property.

The Grid’s IsClippedToBounds=”True” property value makes sure it will cut off any inner elements that will render themselves out of the bounds of Grid. You can set whatever the HeightRequest or WidthRequest as you wish if you want to customize this even further.

Now speaking of the Label and Image you can see how I’m using the advantage of HorizontalOptions to align the elements as whatever the way I wish along with the Margin property of them, adding space wherever I wish. In here we have pushed the Label to the beginning of the Button and the Icon to the End of the Button horizontally.

Next the  InputTransparent=”True” comes in solving the touch issue, which will pass the touch action down to the Button element when the user clicks on it, giving the exact effect of a Button. The use of Image element we can now set whatever the size we wish for our Icon inside the button and adjust its Aspect property and so on.

And let’s try something else as well! Lets have a Button which has its Text and Icons aligned to the Right most corner.

<!--  Button with Text and Icon  -->
<Grid
    Grid.Row="0"
    Grid.Column="1"
    HeightRequest="40"
    HorizontalOptions="Fill"
    IsClippedToBounds="True"
    VerticalOptions="Center">

    <!--  Button Control  -->
    <Button Grid.ColumnSpan="2" BackgroundColor="#2196F3">
        <Button.Margin>
            <OnPlatform x:TypeArguments="Thickness">
                <On Platform="Android" Value="-4,-6,-4,-5" />
                <On Platform="iOS" Value="0" />
            </OnPlatform>
        </Button.Margin>
    </Button>

    <!--  Text Label  -->
    <Label
        Grid.Column="0"
        Margin="0,0,5,0"
        FontAttributes="Bold"
        FontSize="Small"
        HorizontalOptions="End"
        HorizontalTextAlignment="End"
        InputTransparent="True"
        Text="favs"
        TextColor="White"
        VerticalOptions="Center"
        VerticalTextAlignment="Center" />

    <!--  Icon Image  -->
    <Image
        Grid.Column="1"
        Margin="0,0,10,0"
        HeightRequest="30"
        HorizontalOptions="End"
        InputTransparent="True"
        Source="{extensions:ImageResource XFHacks.Resources.staricon.png}"
        VerticalOptions="Center"
        WidthRequest="30" />

    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*" />
        <ColumnDefinition Width="Auto" />
    </Grid.ColumnDefinitions>
</Grid>

 

Here’s another example where I have pushed the Image Icon to the End of the Button and the Label to be following it horizontally.

You can follow the same implementation and have our Button’s Text and Icon aligned t other Left most corner.

Now just like that you can customize all the aspects of a Button using this hack I just shared, just set up the Label and Icon with whatever the properties and customization as you wish on top of a Button. That’s it!

 Important: You could also move that whole piece of XAML to a separate XAML file, so that you could set it up as a reusable Control in your project! 😉

Fire it up!

Let me share some examples I’ve built using this awesomeness!

There you go our awesome Custom Button control running on Android, as you can see with all the preserved Button click effect! 😀

 

Since its completely out of the box Xamarin.Forms, you can run it across all the native platforms and expect the same results! 😉

Grab it on Github!

https://github.com/UdaraAlwis/XFHacks

Well then, that’s it for now. More awesome stuff on the way!

Cheers! 😀 share the love!

Simple Segmented Button Control in pure Xamarin.Forms!

A Segmented Control, or as some call it Grouped Button Control, or Tabbed Button Control or some even call the Rocker Control, is what I’m gonna share with yol today, built 100% from Xamarin.Forms!

Yeah such a platform specific UI element, right out of Xamarin.Forms without a single line of native code, how’s that even? Well if you’ve been following my blog for a while, you know that I’m all about pushing them limits of any given platform and achieve the impossibru! 😉

Whut whut in Xamarin.Forms?

So there’s many different interpretations of this UI elements and also different use cases. Specifically you can see this in native Tabbed Page views in both Android and iOS. And in native platforms they actually have their own Segmented button controls, that allows you to have a set of buttons in a single segment, that allows you to have a selected state, which will let you perform a certain operation, change a value or load a certain View to another element.

So when it comes to Xamarin.Forms, there’s no out of the box UI element that provides this view, unless you use Xamarin.Forms TappedPage control, in which case is impractical if you’re not in need of a Tabbed Page, or worse case in a Content element area where you absolutely can’t use a Page element.

Le Solucioano!

So here’s my solution for this, a Segmented Control in pure Xamarin.Forms, that allows you to have the same exact look and feel and behavior of a native Segmented Control, or a Tabbed Button Control or a Rocker Control or whatever. Lol

Specially no custom renderers, no native code or whatever, just simple and pure Xamarin.Forms! 😉

Sneak Peak

Here’s a sneak peak of what I built, on iOS..

And on Android..

Look at the eh, just like a native control with all the looks and feels and behaviours…

This whole awesome project is hosted up in my Github repo : https://github.com/UdaraAlwis/XFSegmentedControl 

Recipe time…

Buckle up, contains a whole bunch of me hacking around pushing the limits of Xamarin.Forms to achieve some impossibru! 😉

So first thing, we need to keep in mind the aspect of having the same look and feel of a native Segmented control, in aspect of both Android and iOS, therefore we’re going to be using a lot of platform specific properties in XAML and code behind.

We are going to have two Buttons inside a Layout, to emulate the two segmented Buttons. The layout is going to be a Xamarin.Forms Frame, since it has the property CornerRadius, which is vital to gain the curved corners appearance for iOS, and Border property, which we can use to draw the border around the element for iOS. As of Android we can disregard both of those properties. Also don’t forget about the IsClippedToBounds property which all the Layout elements has in Xamarin.Forms, allowing you to crop out of bounds elements inside the layout, which will allow us to have that curved corners in iOS without the button borders popping out of it.

So you might say as of the Button we could use a Label or something and then use a Tap Gesture to handle the click event. Nope! I like the perfection of whatever I’m building! 😉 Therefore we’re going to use actual Xamarin.Forms Button control, now hold on…

Now speaking of the Buttons, we can’t use Buttons with text inside, since the default behaviour of a button restricts the visibility of Text inside it. Therefore we’re going to use a little hack I have always used, that is placing one element over another inside a Grid view. So we are going to use a Button without text inside of it, and then a Label on top of it that represents the Text of the Segmented Button. So you’re probably worries about the Button click behaviour since we’re laying out a Label on top of it, but hello don’t worry, that’s where InputTransparent comes into rescue, passing down the touch even down to the Button straight away! So on selection of the Button we shall do the necessary changes to show the IsSelected status.

We are going to assign name identifiers to our elements in this control to handle some of the code behind magic as well, in case you wondered when you see the code! 😀

Also not to mention that we’re going to maintain properties inside the custom control, like Colors, Text, Selected Button Index properties and also an EventHandler to inform the changes of the Segment button selection.

Well that’s pretty much it, with a bit more details to be gotten into later.

XAML time…

We’re going to create a custom control elements that’s going to be independent and reusable anywhere in the project. Let’s call it SimSegmentedControl, thus denoting “Simple Segmented Control”!

<?xml version="1.0" encoding="UTF-8" ?>
<ContentView
    x:Class="XFSegmentedControl.Simple.Controls.SimegmentedControl"
    xmlns="http://xamarin.com/schemas/2014/forms"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:system="clr-namespace:System;assembly=netstandard">
    <ContentView.Content>
	
	<!--  Rest of content goes here (Next code snippet) -->
	
    </ContentView.Content>
</ContentView>

 

Now let’s get into the inside elements of our SimSegmentedControl, which is basically the Frame Layout that I explained before.

<Frame
    x:Name="FrameView"
    Padding="0"
    IsClippedToBounds="True">
    <!--  Platform specific customization values for the border  -->
    <Frame.HasShadow>
        <OnPlatform x:TypeArguments="system:Boolean">
            <On Platform="Android" Value="False" />
            <On Platform="iOS" Value="True" />
        </OnPlatform>
    </Frame.HasShadow>
    <Frame.CornerRadius>
        <OnPlatform x:TypeArguments="system:Single">
            <On Platform="Android" Value="0" />
            <On Platform="iOS" Value="5" />
        </OnPlatform>
    </Frame.CornerRadius>
    <Frame.HeightRequest>
        <OnPlatform x:TypeArguments="system:Double">
            <On Platform="Android" Value="50" />
            <On Platform="iOS" Value="35" />
        </OnPlatform>
    </Frame.HeightRequest>
    <!--  Platform specific customization values for the border  -->

    
    <!--  Segmented Buttons go in here (Next code snippet)  -->
    
</Frame>

 

As you can see I have added a whole bunch of platform specific customization values for Android and iOS to achieve the design we’re targeting for, such as CornerRadius and Height.

Then let’s add our Segmented Button elements, just to make it easier let’s identify each of them as “Tab Button” element.

<Grid ColumnSpacing="0">

    <!--  Tab button 1  -->
    <Grid Grid.Column="0" IsClippedToBounds="True">
        <Button
            x:Name="Tab1ButtonView"
            Margin="-2,-3,-2,0"
            Clicked="Tab1Button_OnClicked" />
        <Label
            x:Name="Tab1LabelView"
            FontAttributes="Bold"
            FontSize="Medium"
            HorizontalOptions="CenterAndExpand"
            InputTransparent="True"
            Text="Tab 1"
            VerticalOptions="CenterAndExpand" />
        <BoxView
            x:Name="Tab1BoxView"
            HeightRequest="2"
            InputTransparent="True"
            IsVisible="False"
            VerticalOptions="End" />
    </Grid>
    <!--  Tab button 1  -->

    <!--  Tab button 2  -->
    <Grid Grid.Column="1" IsClippedToBounds="True">
        <Button
            x:Name="Tab2ButtonView"
            Margin="-2,-3,-2,0"
            Clicked="Tab2Button_OnClicked" />
        <Label
            x:Name="Tab2LabelView"
            FontAttributes="Bold"
            FontSize="Medium"
            HorizontalOptions="CenterAndExpand"
            InputTransparent="True"
            Text="Tab 2"
            VerticalOptions="CenterAndExpand" />
        <BoxView
            x:Name="Tab2BoxView"
            HeightRequest="2"
            InputTransparent="True"
            IsVisible="False"
            VerticalOptions="End" />
    </Grid>
    <!--  Tab button 2  -->

    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*" />
        <ColumnDefinition Width="*" />
    </Grid.ColumnDefinitions>
</Grid>

 

Voila! behold the two button elements, with all the platform specific customizations, just like how I explained before, Label on top of a Button inside a Grid layout. Also you may have noticed the Margin property that I have used with “-2,-3,-2,0”, which is to stretch out the empty border line of the buttons out of the Grid so it crops out with the IsClippedToBounds property.

And the BoxView is to emulate the bottom line we have in Android look and feel of the Segmented Control.

Code-behind time…

Now this is where we’re basically going to handle all the action in our SegmentedControl!

So I’m not going to spoon feed the whole code in this blog post, since its going to be a pretty lengthy one, so I’ll be cutting out most of the repetitive code which you can easily figure out yourself or just check out on my github repo where I have committed this whole project code.

So like I explained at beginning we’re going to have a bunch of properties that are going to handle all the customization values such as Color, Text, SelectedIndex, EventHandler and so on. And then apply a whole bunch of code behind customization for platform specific look and feels, along with the handling of Segment button click event behavior.

[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class SimSegmentedControl : ContentView
{
    public static readonly BindableProperty PrimaryColorProperty
        = BindableProperty.Create(
            nameof(PrimaryColor),
            typeof(Color),
            typeof(SimSegmentedControl),
            Color.CornflowerBlue);

    public Color PrimaryColor
    {
        get { return (Color)GetValue(PrimaryColorProperty); }
        set { SetValue(PrimaryColorProperty, value); }
    }

    // SecondaryColorProperty

    // Tab1TextProperty

    // Tab2TextProperty

    // SelectedTabIndexProperty
    
    public event EventHandler<SelectedTabIndexEventArgs> SelectedTabIndexChanged;

    public SimSegmentedControl()
    {
        InitializeComponent();
    }

    /// <summary>
    /// load up the customizations and applying
    /// properties when the element has rendered
    /// </summary>
    protected override void OnParentSet()
    {
        base.OnParentSet();
        
        // Setting up platform specific properties for Android and iOS
        if (Device.RuntimePlatform == Device.Android)
        {
            Tab1LabelView.FontSize
                = Device.GetNamedSize(NamedSize.Medium, Tab1LabelView);
            Tab2LabelView.FontSize
                = Device.GetNamedSize(NamedSize.Medium, Tab1LabelView);

            Tab1ButtonView.BackgroundColor = PrimaryColor;
            Tab2ButtonView.BackgroundColor = PrimaryColor;

            Tab1BoxView.Color =
            Tab2BoxView.Color =
            Tab1LabelView.TextColor =
            Tab2LabelView.TextColor = SecondaryColor;
        }
        else if (Device.RuntimePlatform == Device.iOS)
        {
            Tab1LabelView.FontSize
                = Device.GetNamedSize(NamedSize.Small, Tab1LabelView);
            Tab2LabelView.FontSize
                = Device.GetNamedSize(NamedSize.Small, Tab1LabelView);

            Tab1ButtonView.BackgroundColor =
            Tab2ButtonView.BackgroundColor = PrimaryColor;

            FrameView.BorderColor =
            Tab1LabelView.TextColor =
            Tab2LabelView.TextColor = SecondaryColor;
        }

        Tab1LabelView.Text = Tab1Text;
        Tab2LabelView.Text = Tab2Text;

        // setting up default values
        SelectTab1();
        SelectedTabIndex = 1;
        SendSelectedTabIndexChangedEvent();
    }

    private void Tab1Button_OnClicked(object sender, EventArgs e)
    {
        SelectTab1();
        SelectedTabIndex = 1;
        SendSelectedTabIndexChangedEvent();
    }

    private void Tab2Button_OnClicked(object sender, EventArgs e)
    {
        SelectTab2();
        SelectedTabIndex = 2;
        SendSelectedTabIndexChangedEvent();
    }
    
    // SelectTab1()
    
    // SelectTab2()
    
    // SendSelectedTabIndexChangedEvent()
}

 

So we PrimaryColor and SecondaryColor which handles the two main colors that is styling our SimSegmentedControl, which is exactly how it being used in native version of this control as well, just two simple Colors styling the whole element.

Then Tab1Text and Tab2Text property to handle the Text that needs to be displayed in the Segmented buttons.

As you can see OnParentSet (this is when the View is rendered in memory and just about to be displayed on the Page) we’re applying all the platform specific customization for the elements in our SimSegmentedControl. Then you can see we’re setting the Tab1 and Tab2 text properties to our Labels, which is not actually good practice, but I was too lazy to add that in the PropertyChangedEvent handler of those respective bindable properties. After that at the end you can see we’re setting the default values.

Also the SelectedTabIndexChanged EventHandler is there to notify any outside element who wants to be aware of the selected Tab in our SimSegmentedControl, so they can perform whatever the action based on it.

Then let me get into the SelectTab1(), SelectTab2() and SendSelectedTabIndexChangedEvent methods.

private void SelectTab1()
{
    // set up platform specific
    // properties for SelectTab1 event
    if (Device.RuntimePlatform == Device.Android)
    {
        Tab1BoxView.IsVisible = true;
        Tab2BoxView.IsVisible = false;
    }
    else if (Device.RuntimePlatform == Device.iOS)
    {
        Tab1ButtonView.BackgroundColor = SecondaryColor;
        Tab2ButtonView.BackgroundColor = PrimaryColor;

        Tab1LabelView.TextColor = PrimaryColor;
        Tab2LabelView.TextColor = SecondaryColor;
    }
}

private void SelectTab2()
{
    // set up platform specific
    // properties for SelectTab2 event
    if (Device.RuntimePlatform == Device.Android)
    {
        Tab1BoxView.IsVisible = false;
        Tab2BoxView.IsVisible = true;
    }
    else if (Device.RuntimePlatform == Device.iOS)
    {
        Tab1ButtonView.BackgroundColor = PrimaryColor;
        Tab2ButtonView.BackgroundColor = SecondaryColor;

        Tab1LabelView.TextColor = SecondaryColor;
        Tab2LabelView.TextColor = PrimaryColor;
    }
}

/// <summary>
/// Invoke the SelectedTabIndexChanged event
/// for whoever has subscribed so they can
/// use it for any reative action
/// </summary>
private void SendSelectedTabIndexChangedEvent()
{
    var eventArgs = new SelectedTabIndexEventArgs();
    eventArgs.SelectedTabIndex = SelectedTabIndex;

    SelectedTabIndexChanged?.Invoke(this, eventArgs);
}

--------------

public class SelectedTabIndexEventArgs : EventArgs
{
    public int SelectedTabIndex { get; set; }
}

 

So there you can see in SelectTab1() we’re setting up the necessary customization for the Selected state of our Segmented Button for both Android and iOS, such as the BackgroundColor, TextColor and whatnot. And then in SelectTab2() we’re doing the exact opposite customization, Button 1 -> Unselected and Button 2 -> Selected appearance.

Then in the SendSelectedTabIndexChangedEvent we’re basically broadcasting the selected Tab index of our SimSegmentedControl with the SelectedTabIndex property value.

Time to consume!

Let’s use this awesome SimSegmentedControl in our Page shall we?!!! 😀

<local:SimSegmentedControl
	x:Name="SegmentedControlView"
	PrimaryColor="CornflowerBlue"
	SecondaryColor="White"
	SelectedTabIndexChanged="SegmentedControlView_SelectedTabIndexChanged"
	Tab1Text="Monkeys"
	Tab2Text="Minions">
	<local:SimSegmentedControl.Padding>
		<OnPlatform x:TypeArguments="Thickness">
			<On Platform="Android" Value="0" />
			<On Platform="iOS" Value="10,0,10,10" />
		</OnPlatform>
	</local:SimSegmentedControl.Padding>
</local:SimSegmentedControl>

 

Easy peasy, you just set the property values such as PriaryColor, SecondaryColor and so on that we created in our SimSegmentedControl and do a bit of customization if you wish to 😉 like I’ve added some padding for iOS!

In case if you’re wondering how to use the SelectedTabIndexChanged, you basically subscribe to that event and perform whatever the action you desire, whether it be changing some values, or swapping some Views or whatever your requirement is!

private void SegmentedControlView_SelectedTabIndexChanged
			(object sender, SelectedTabIndexEventArgs e)
{
	if (e.SelectedTabIndex == 1)
	{
		ContentView1.IsVisible = true;
		ContentView2.IsVisible = false;
	}
	else if (e.SelectedTabIndex == 2)
	{
		ContentView1.IsVisible = false;
		ContentView2.IsVisible = true;
	}
}

 

Just like that!

Let’s fire it up!

Let’s see this beauty in action now! 😀

Here we go baby! iOS and Android running side by side…

 

Let’s change up a bit of the colors shall we!

Woot, whatever the color combination you wish! 😉

Improvement suggestions..

Well if you ask me this is not the exact implementation I used for my actual requirement, this is more of a very simple implementation of it.

But there’s many ways to improve this. One would be adding Command for the selected Tab Index changed property handling. Also add both way handling of SelectedTabIndex so that we can set the default selected Tab on the go. Specially add dynamic Tab Buttons to the SimSegmentedControl at run time without just limiting to 2 buttons. 😉

Well your imagination is the limit fellas! 😀

This whole awesome project is hosted up in my Github repo : https://github.com/UdaraAlwis/XFSegmentedControl 

Check out the Part 2 of this article: Advanced Segmented Button Control in pure Xamarin.Forms!

Cheers! 😀 Keep on going my fellow devs!

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