Android Drawing monitoring Interface Onpredrawlistener detailed

public static Interface Viewtreeobserver.onpredrawlistener

Let's look at the definitions in the API:

class overview:

The interface defined for the callback function to be executed when the view tree is about to be drawn.

Common methods:

Public abstract Boolean Onpredraw ()

The callback function to execute when the view tree is about to be drawn. At this point all views are measured and the frame is finalized. The client can use this method to adjust the scrolling border, or even to request a new layout before drawing.

In conclusion, Viewtreeobserver is used to help us monitor certain changes in certain view.

One of the most common areas where we get the long and wide measurements of the view is in other parts of the OnDraw.

Android Drawing monitoring Interface Onpredrawlistener detailed