When does setVisibility() not fire onVisibilityChanged() in a view?

Question

I have a problem where in a specific situation when I call setVisibility(GONE) inside my custom view, its onVisibilityChanged method doesn't get called and it actually doesn't hide the view although getVisibility() returns 8 (or GONE) afterwards.

Here is how I know the visibility changes but onVisibilityChanged is not called.

@Override
protected void onVisibilityChanged(@NonNull View changedView, int visibility) {
    Log.i(LOG_TAG, "onVisibilityChanged: " + visibility);
    super.onVisibilityChanged(changedView, visibility);
}

@Override
public void setVisibility(int visibility) {
    super.setVisibility(visibility);
    Log.i(LOG_TAG, "setVisibility: " + visibility);
}

public void hide(){
    Log.i(LOG_TAG, "before hide visibility: " + getVisibility());
    setVisibility(GONE);
    Log.i(LOG_TAG, "after hide visibility: " + getVisibility());
}

Normally when I call hide() I see these lines in the log:

before hide visibility: 0

onVisibilityChanged: 8

setVisibility: 8

after hide visibility: 8

But in a spicific situation when I call hide() I get these lines in the log and the view isn't hidden afterwards although getVisibility() returns 8:

before hide visibility: 0

setVisibility: 8

after hide visibility: 8

So when in general does this happen? When does setVisibility not call onVisibilityChanged?

Don't ask what my specific situation is. But please provide every general situation where this might happen.

Answer 1

It is called only when the view is attached in the hierarchy.

The call to setVisibility looks like this:

public void setVisibility(@Visibility int visibility) {
    setFlags(visibility, VISIBILITY_MASK);
}

The setFlags method is a long one where a bunch of different view properties are changed and handled, but the noticable part is this:

 if ((changed & VISIBILITY_MASK) != 0) {
      // if visiblity changed...
      ...
      if (mAttachInfo != null) { // true if attached in view hierarchy
            dispatchVisibilityChanged(this, newVisibility); // onVisibilityChanged is called from here 
            ...

---

So you will see your described behaviour on a view that's not attached to a fragment or activity.