Summary
The issue described is a black screen appearing at the bottom of the screen when the keyboard hides in a Xamarin app for Android 16. This occurs after the user finishes typing and clicks “done” or taps outside the entry field, causing the screen to resize and get stuck halfway, resulting in a black screen.
Root Cause
The root cause of this issue is related to the way the Xamarin.Forms app handles the keyboard visibility and screen resizing on Android 16. The AdjustResize and AdjustPan properties are not working as expected, and the custom renderer’s attempt to force a layout refresh is not sufficient to prevent the black screen from appearing.
Why This Happens in Real Systems
This issue occurs in real systems because of the complexities of handling keyboard visibility and screen resizing on Android devices. The Android operating system has different behaviors for different versions and devices, making it challenging to find a universal solution. Additionally, the Xamarin.Forms framework may not always provide the necessary tools to handle these complexities.
Real-World Impact
The real-world impact of this issue is a poor user experience, as the black screen can be confusing and frustrating for users. It can also lead to a loss of trust in the app and potentially cause users to abandon it.
Example or Code
private void RegisterKeyboardListener()
{
_rootView = Window.DecorView.RootView;
_globalLayoutHandler = (sender, args) =>
{
var rect = new Android.Graphics.Rect();
_rootView.GetWindowVisibleDisplayFrame(rect);
int screenHeight = _rootView.Height;
int keypadHeight = screenHeight - rect.Bottom;
bool isKeyboardVisible = keypadHeight > screenHeight * 0.15;
_rootView.Post(() =>
{
_rootView.PostDelayed(() =>
{
_rootView.RequestLayout();
_rootView.Invalidate();
}, 16);
});
_keyboardWasVisible = isKeyboardVisible;
};
_rootView.ViewTreeObserver.GlobalLayout += _globalLayoutHandler;
}How Senior Engineers Fix It
Senior engineers fix this issue by using a combination of techniques, such as using the WindowSoftInputMode attribute in the AndroidManifest.xml file, adjusting the layout parameters of the root view, and using a custom renderer to handle the keyboard visibility and screen resizing. They also ensure that the solution is tested on different Android versions and devices to ensure compatibility.
Why Juniors Miss It
Juniors may miss this issue because they may not have experience with the complexities of handling keyboard visibility and screen resizing on Android devices. They may also not be familiar with the Xamarin.Forms framework and its limitations, leading to a lack of understanding of how to properly handle this issue. Additionally, juniors may not have the necessary debugging skills to identify the root cause of the problem and develop an effective solution.