Xamarin.Forms Animation With Triggers

Sumit Singh Sisodia
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In this post, I have created an example of animation with triggers, This time, we are talking about triggers.

Xamarin.Forms have a powerful class named Trigger. I want to show you stack layout flipping with animation which I have created with Trigger.

First, let us create a folder named Triggers. Then, create a class with the name SwitchLayout.

Then, write the following code in that.

public class SwitchLayout : TriggerAction<Button>
{
public enum AnimationDirection
{ Left, Right }
protected override async void Invoke(Button sender)
{
View Viewhide = null;
View Viewshow = null;
if (TargetElement != null)
{
// This is For Finding TargetView
Viewshow = ((View)sender.Parent.Parent).FindByName<View>(TargetElement);
if (Viewshow != null)
{
// This is For Finding SourceView
if (SourceElement != null)
{
Viewhide = ((View)sender.Parent.Parent).FindByName<View>(SourceElement);
if (Viewhide != null)
{
await PerformAnimation(Viewhide, Viewshow);
}
}
}
}
}
public string SourceElement { get; set; }
public string TargetElement { get; set; }
public AnimationDirection Direction { get; set; }
private async Task PerformAnimation(View ViewElementHide, View ViewElementShow)
{
int hideStart = 0;
int hideStop = 0;//if you want to use another rotate animation So you Comment Out and remove 0//(Direction == AnimationDirection.Left ? -90 : 90);
int showStart = 0;//if you want to use another rotate animation So you Comment Out and remove 0//(Direction == AnimationDirection.Left ? 90 : 270);
int showStop = 0;//if you want to use another rotate animation So you Comment Out and remove 0//(Direction == AnimationDirection.Left ? 0 : 360);
await ViewElementHide.RotateYTo(hideStart, 0);
await ViewElementShow.RotateYTo(showStart, 0);
await ViewElementShow.ScaleTo(0.2, 0);
ViewElementShow.IsVisible = true; // This is rotated at 90 or 270 degrees
// Animate
ViewElementHide.FadeTo(0.5, 100, Easing.SinOut);
ViewElementHide.ScaleTo(0.2, 100, Easing.Linear);
await ViewElementHide.RotateYTo(hideStop, 150, Easing.Linear);
ViewElementShow.FadeTo(1, 100, Easing.SinIn);
ViewElementShow.ScaleTo(1, 150, Easing.Linear);
await ViewElementShow.RotateYTo(showStop, 150, Easing.Linear);
ViewElementHide.IsVisible = false;
}
}

Here is the XAML code.

You need to add the reference like this.

xmlns:triggers="clr-namespace:FlipAnimation.Triggers"

<ContentPage.Content>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Image Opacity="1"
Source="icon.png"
Aspect="AspectFill"/>
<Grid>
<Grid.Padding>
<OnPlatform x:TypeArguments="Thickness">
<OnPlatform.iOS>
0, 20, 0, 0
</OnPlatform.iOS>
<OnPlatform.Android>
0, 0, 0, 0
</OnPlatform.Android>
</OnPlatform>
</Grid.Padding>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<StackLayout Grid.Row="0">
<Label Text="Login"
TextColor="White"
HorizontalTextAlignment="Center" />
</StackLayout>
<StackLayout Grid.Row="1">
<!--<ActivityIndicator x:Name="actInd" IsRunning="False" IsVisible="False" Color="Blue" />
<Label x:Name="lblBusyMsg" IsVisible="False" Text="My Message" >
<Label.Font>
<OnPlatform x:TypeArguments="Font">
<OnPlatform.iOS>Small</OnPlatform.iOS>
</OnPlatform>
</Label.Font>
</Label>
<Label x:Name="labelErrorMessage" IsVisible="False" Text="MY Message" TextColor="Red">
<Label.Font>
<OnPlatform x:TypeArguments="Font">
<OnPlatform.iOS>Small</OnPlatform.iOS>
</OnPlatform>
</Label.Font>
</Label>-->
</StackLayout>
<StackLayout x:Name="stLog"
Grid.Row="1" Grid.Column="0"
IsVisible="True"
Padding="20,20,20,20"
>
<Entry Placeholder="Email" Text="" />
<Entry Placeholder="Password" Text=""
IsPassword="True" />
<Button Text="Login" Clicked="Login_Clicked" />
<Button Text="Register" >
<Button.Triggers>
<EventTrigger Event="Clicked">
<triggers:SwitchLayout SourceElement="stLog" TargetElement="stReg" Direction="Right" />
</EventTrigger>
</Button.Triggers>
</Button>
<Button Text="Forgot Password">
<Button.Triggers>
<EventTrigger Event="Clicked">
<triggers:SwitchLayout SourceElement="stLog" TargetElement="stForgotPass" Direction="Right" />
</EventTrigger>
</Button.Triggers>
</Button>
<Button Text="Change Password">
<Button.Triggers>
<EventTrigger Event="Clicked">
<triggers:SwitchLayout SourceElement="stLog" TargetElement="stChangePass" Direction="Right" />
</EventTrigger>
</Button.Triggers>
</Button>
</StackLayout>
<StackLayout x:Name="stReg" Grid.Row="1" Grid.Column="0" IsVisible="False" Padding="20" >
<Entry Placeholder="Email" Text="" />
<Entry Placeholder="First name" Text="" />
<Entry Placeholder="Last name" Text="" />
<Button Text="Register" Clicked="Register_Clicked" />
<Button Text="Cancel">
<Button.Triggers>
<EventTrigger Event="Clicked">
<triggers:SwitchLayout SourceElement="stReg" TargetElement="stLog" Direction="Left" />
</EventTrigger>
</Button.Triggers>
</Button>
</StackLayout>
<StackLayout x:Name="stForgotPass" Grid.Row="1" Grid.Column="0" IsVisible="False" Padding="20" >
<Entry Placeholder="Email"
Text="" />
<Button Text="Send email" Clicked="ForgetPass_Clicked"/>
<Button Text="Cancel">
<Button.Triggers>
<EventTrigger Event="Clicked">
<triggers:SwitchLayout SourceElement="stForgotPass" TargetElement="stLog" Direction="Left" />
</EventTrigger>
</Button.Triggers>
</Button>
</StackLayout>
<StackLayout x:Name="stChangePass" Grid.Row="1" Grid.Column="0" IsVisible="False" Padding="20" >
<Entry Placeholder="Old password"
IsPassword="True" />
<Entry Placeholder="New password" IsPassword="True" />
<Entry Placeholder="Confirm password" IsPassword="True" />
<Button Text="OK" Clicked="ChangePass_Clicked"/>
<Button Text="Cancel">
<Button.Triggers>
<EventTrigger Event="Clicked">
<triggers:SwitchLayout SourceElement="stChangePass" TargetElement="stLog" Direction="Left" />
</EventTrigger>
</Button.Triggers>
</Button>
</StackLayout>
</Grid>
</Grid>
</ContentPage.Content>