[FIXED] Android Bottom Sheet after state changed

Issue

I have a screen with a bottomsheet, but for the transition, and animation to work between activities I need the bottomsheet to be collapsed when the user goes on back pressed. I tried this

@Override
public void onBackPressed(){
    if (mBottomSheetBehavior.getState() == BottomSheetBehavior.STATE_COLLAPSED) {
        super.onBackPressed();
    } else {
        mBottomSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
        super.onBackPressed();
    }

    mShowingBack = false;
}

However, that doesn't work as the activity goes back while the bottomsheet is only halfway down.

Solution

BottomSheetBehavior.STATE_COLLAPSED doesn't hide all the BottomSheet, it just sets the height of the view to whatever you set with setPeekHeight() or behavior_peekHeight in the xml :) but putting that aside... you should call super.onBackPressed() inside a BottomSheetBehaviorCallback when the state of the BottomSheet is STATE_COLLAPSED, like this:

BottomSheetBehavior behavior = BottomSheetBehavior.from(mBottomSheetBehavior);  
behavior.addBottomSheetCallback(new BottomSheetCallback() {  
   @Override  
   public void onStateChanged(@NonNull View bottomSheet, int newState) {  
     if (newState == BottomSheetBehavior.STATE_COLLAPSED && mIsCollapsedFromBackPress){
        mIsCollapsedFromBackPress = false;
        super.onBackPressed();
     }
   }  

  @Override  
  public void onSlide(@NonNull View bottomSheet, float slideOffset) {  
     // React to dragging events  
  }  
});

and your backPressed() method should look like this:

@Override
public void onBackPressed(){
    mIsCollapsedFromBackPress = true;
    mBottomSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
}

Answered By - amilcar-sr
Answer Checked By - Mildred Charles (JavaFixing Admin)