Emit signal / notification when the virtual keyboard opens and closes

[dominiks]

Working on a mobile app I encountered the issue that the virtual keyboard that opens when editing a LineEdit blocks the user's view of the UI. It would be easy to fix this by adding a spacer Control that takes the height of DisplayServer.virtual_keyboard_get_height() ( / get_window().content_scale_factor actually) to move all content out of that zone but there is no way to be notified when the view opens. You can enable this spacer element when the LineEdit receives focus and hide it when the focus is lost but the virtual keyboard can open and close without losing focus of the control.

Therefore I think it would be good to have a signal or a notification whenever the virtual keyboard is opened or closed. Currently the DisplayServer handles everything regarding the virtual keyboard but servers don't send signals, I think. Alternatively the event could be emitted by LineEdit and TextEdit as they automatically open the keyboard.

[duongxinh2003]

Any update?

[Calinou]

To my knowledge, nobody has started working on this yet. It should be possible but I'm not sure if the LineEdit/TextEdit sending the signal will lead to good usability.

Out of curioisity, what are you trying to achieve by having this signal available?

[roonskipp]

I would like this signal so I can resize a container to make sure part of my UI is visible right above the keyboard.
I now do a check when I handle user input, but it feels unecessary to resize the container on every input change. I would rather do it on a signal emitted when the virtual keyboard is shown / hidden.

[JoNax97]

Would it make sense to implement it as an input event?

[Calinou]

It feels strange to have an input event type for a single set of actions (virtual keyboard open/close). A signal seems more appropriate to me.

[JoNax97]

Fair point. Could it be put in some global place? It would be weird to have it be a signal of an object instance.

[andris1]

Just want to add that I'm in a very similar position to @dominiks' - I'd like to move a bunch of UI above the virtual keyboard when it's open.

[Satellaa]

Any update guys?

[JoNax97]

I don't think anyone has gotten around to implementing this

[Gromph]

We have implemented this in a custom internal java android plugin. It's got some hacks in it that may not be needed anymore, also I copied and pasted this out of a larger plugin, so it may not be a complete example, but here is how we did it:

public class MonitorKeyboardAndroid extends GodotPlugin {
	private static final String TAG = "MonitorKeyboardAndroid ";
	int mVirtualKeyboardHeight;
	int mVirtualKeyboardHeightError;
	boolean mKeyboardShownOnce = false;

	@Nullable
	public View onMainCreate(Activity activity) {
		// listen for layout changes which generally indicates keyboard being shown/hidden and emit signals
		getGodot().getRenderView().getView().getViewTreeObserver().addOnGlobalLayoutListener(() -> {

			// Calculate keyboard height, this is copied from Godot.java::onVideoInit
			// It however is wrong, see https://github.com/godotengine/godot/issues/41388
			// Apparently it doesn't add the height of the android navigation bar
			// on my Pixel 5a with Android 12 the nav bar is a black bar with a down arrow to hide keyboard
			// When the keyboard is hidden keyboardHeight will be negative, it happens that this is the height 
			// of the nav bar, so adding it to keyboardHeight fixes it. Hopefully we can remove this when 41388 is fixed
			Point fullSize = new Point();
			getGodot().getActivity().getWindowManager().getDefaultDisplay().getSize(fullSize);
			Rect gameSize = new Rect();
			getGodot().getRenderView().getView().getWindowVisibleDisplayFrame(gameSize);
			final int keyboardHeight = fullSize.y - gameSize.bottom;

			if(keyboardHeight <= 0) {
				mVirtualKeyboardHeightError = keyboardHeight;
				mVirtualKeyboardHeight = 0;
			}

			if(android.os.Build.MANUFACTURER.equals("Amazon") && isTV() && keyboardHeight > fullSize.y * 0.75)
			{
				// Amazon Fire TV will trigger this callback when the keyboard is being hidden with mVirtualKeyboardHeight between 1027 and 1080
				// It causes our boxes to resizes rreally small and then large again causing a flicker, so just ignore it
				//Log.w(TAG, String.format("MonitorKeyboardAndroid::addOnGlobalLayoutListener ignoring large keyboard on Amazon Fire TV"));
			}
			else if(keyboardHeight > 0) {
				mVirtualKeyboardHeight = keyboardHeight + Math.abs(mVirtualKeyboardHeightError);
				mKeyboardShownOnce = true;
				emitSignal("keyboard_shown");
			}
			else {
				// only emit hidden signal if keyboard has been shown at least once. This hopefully fixes exception starting game where it
				// immediately tried to emit signal before signal was registered
				if(mKeyboardShownOnce)
					emitSignal("keyboard_hidden");
			}
		});
	}
	public boolean isTV() {
		PackageManager packageManager = getGodot().getActivity().getPackageManager();
		return packageManager.hasSystemFeature(PackageManager.FEATURE_LEANBACK);
	}
	@NonNull
	@Override
	public String getPluginName() {
		return "MonitorKeyboardAndroid ";
	}

	@NonNull
	@Override
	public Set<SignalInfo> getPluginSignals() {
		Set<SignalInfo> signals = new ArraySet<>();
		signals.add(new SignalInfo("keyboard_shown"));
		signals.add(new SignalInfo("keyboard_hidden"));
		return signals;
	}
}