Page Lifecycle Events on Android
This Android platform-specific is used to disable the Disappearing and Appearing page events on application pause and resume respectively, for applications that use AppCompat. In addition, it includes the ability to control whether the soft keyboard is displayed on resume, if it was displayed on pause, provided that the operating mode of the soft keyboard is set to WindowSoftInputModeAdjust.Resize.
Note
Note that these events are enabled by default to preserve existing behavior for applications that rely on the events. Disabling these events makes the AppCompat event cycle match the pre-AppCompat event cycle.
This platform-specific can be consumed in XAML by setting the Application.SendDisappearingEventOnPause, Application.SendAppearingEventOnResume, and Application.ShouldPreserveKeyboardOnResume attached properties to boolean values:
<Application ...
xmlns:android="clr-namespace:Xamarin.Forms.PlatformConfiguration.AndroidSpecific;assembly=Xamarin.Forms.Core" xmlns:androidAppCompat="clr-namespace:Xamarin.Forms.PlatformConfiguration.AndroidSpecific.AppCompat;assembly=Xamarin.Forms.Core"
android:Application.WindowSoftInputModeAdjust="Resize"
androidAppCompat:Application.SendDisappearingEventOnPause="false"
androidAppCompat:Application.SendAppearingEventOnResume="false"
androidAppCompat:Application.ShouldPreserveKeyboardOnResume="true">
...
</Application>
Alternatively, it can be consumed from C# using the fluent API:
using Xamarin.Forms.PlatformConfiguration;
using Xamarin.Forms.PlatformConfiguration.AndroidSpecific;
using Xamarin.Forms.PlatformConfiguration.AndroidSpecific.AppCompat;
...
Xamarin.Forms.Application.Current.On<Android>()
.UseWindowSoftInputModeAdjust(WindowSoftInputModeAdjust.Resize)
.SendDisappearingEventOnPause(false)
.SendAppearingEventOnResume(false)
.ShouldPreserveKeyboardOnResume(true);
The Application.Current.On<Android> method specifies that this platform-specific will only run on Android. The Application.SendDisappearingEventOnPause method, in the Xamarin.Forms.PlatformConfiguration.AndroidSpecific.AppCompat namespace, is used to enable or disable firing the Disappearing page event, when the application enters the background. The Application.SendAppearingEventOnResume method is used to enable or disable firing the Appearing page event, when the application resumes from the background. The Application.ShouldPreserveKeyboardOnResume method is used control whether the soft keyboard is displayed on resume, if it was displayed on pause, provided that the operating mode of the soft keyboard is set to WindowSoftInputModeAdjust.Resize.
The result is that the Disappearing and Appearing page events won't be fired on application pause and resume respectively, and that if the soft keyboard was displayed when the application was paused, it will also be displayed when the application resumes:
