Android - Understanding View.getLocalVisibleRect(Rect)

Question

I\'m looking for any clue to understand this method.

There is no info in official Android\'s SDK documentation about it.

What kind of Rectangle does it return? <

Answer 1

From the JavaDoc of getGlobalVisibleRect:

/**
 * If some part of this view is not clipped by any of its parents, then
 * return that area in r in global (root) coordinates. To convert r to local
 * coordinates (without taking possible View rotations into account), offset
 * it by -globalOffset (e.g. r.offset(-globalOffset.x, -globalOffset.y)).
 * If the view is completely clipped or translated out, return false.
 *
 * @param r If true is returned, r holds the global coordinates of the
 * visible portion of this view.
 * @param globalOffset If true is returned, globalOffset holds the dx,dy
 * between this view and its root. globalOffet may be null.
 * @return true if r is non-empty (i.e. part of the view is visible at the
 * root level.
 */

getLocalVisibleRect calls getGlobalVisibleRect and then makes it local as suggested:

r.offset(-offset.x, -offset.y); // make r local`

So:

• It doesn't return a Rectangle, it returns a boolean. But it can set the parameters of a rectangle you pass, and that must be an android.graphics.Rect rectangle;
• The rectangle r will be filled with local coordinates;
• I'm not sure but I think it's the same for visibile and invisible views, while it should return false for views with visibility="gone"