Remove gestures from Android Q

Question

I have a kids drawing app, but the gestures in Q keep quitting the app. I tried removing the system gesture but it does not seem to work.

In this case, I am trying to exclude the whole screen from system gesture:

List<Rect> exclusionRects = new ArrayList();

public void onLayout(boolean changedCanvas, int left, int top, int right, int bottom) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
        exclusionRects.clear();
        exclusionRects.add(new Rect(left, top, right, bottom));
        setSystemGestureExclusionRects(exclusionRects);
    }
}

score 4 · Answer 1 · answered Aug 13 '19 at 08:07

4

As stated by Google:

First, to ensure reliable and consistent operation, there’s a 200dp vertical app exclusion limit for the Back gesture.

https://android-developers.googleblog.com/2019/08/final-beta-update-official-android-q.html

This means that the operating system will not allow you to override the back gesture fully.

This makes sense as it is a fairly fundamental part of the operating system and they probably don't want to allow apps that remove the gesture entirely, as it is bad for consistency across the platform

answered Aug 13 '19 at 08:07

cameron1024

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What does "200dp vertical app exclusion limit" mean? Isn't the back gesture is on the left (horizontal)? – Lim Thye Chean Aug 13 '19 at 08:09
1

The back gesture is on both the left and right sides, and these are both vertical edges (vertical = up <-> down, horizontal = left <-> right). This means that of the full height of the screen, only 200dp are allowed to be excluded from gesture navigation. I.e. if your screen is 1000dp high, a minimum of 800dp will be used for the gesture no matter what. – cameron1024 Aug 13 '19 at 08:12
_"This makes sense"_ - except that now every drawing app is fundamentally broken because you can't draw on the left/right side of the screen without navigating? wtf?? – BlueRaja - Danny Pflughoeft Mar 26 '23 at 22:15
The three-button navigation mode still exists, but IMO it's a worthwhile tradeoff. I disagree that having a few pixels on either edge of the screen unusable "fundamentally breaks" drawing apps. And even if it does, I'd rather have this than allow apps that I download from the internet (without vetting source code) to disable navigating away from the app. – cameron1024 Mar 27 '23 at 12:06

score 0 · Answer 2 · answered Dec 17 '20 at 09:59

Try this.

Define this code in your Utils class.

 static List<Rect> exclusionRects = new ArrayList<>();
 public static void updateGestureExclusion(AppCompatActivity activity) {
   if (Build.VERSION.SDK_INT < 29) return;
   exclusionRects.clear();
   Rect rect = new Rect(0, 0, SystemUtil.dpToPx(activity, 16), getScreenHeight(activity));
   exclusionRects.add(rect);

   activity.findViewById(android.R.id.content).setSystemGestureExclusionRects(exclusionRects);
 }

 public static int getScreenHeight(AppCompatActivity activity) {
 DisplayMetrics displayMetrics = new DisplayMetrics();
 activity.getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
 int height = displayMetrics.heightPixels;
 return height;
 }

 public static int dpToPx(Context context, int i) {
   return (int) (((float) i) * context.getResources().getDisplayMetrics().density);
 }

Check if your layout is set in that activity where you want to exclude the edge getures and then apply this code.

 // 'content' is the root view of your layout xml.
 ViewTreeObserver treeObserver = content.getViewTreeObserver();
 treeObserver.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
     @Override
     public void onGlobalLayout() {
         content.getViewTreeObserver().removeOnGlobalLayoutListener(this);
         SystemUtil.updateGestureExclusion(MainHomeActivity.this);
     }
 });

We are adding the view width to 16dp to trigger the code when user swipe right from left edge & height to screen height to do it fully left side.

This code works for the whole left edge, for bottom & right edge, you just need to add Rects in the arraylist like written above. — Dev4Life, Dec 18 '20 at 04:00

Remove gestures from Android Q

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