以编程方式设置的边距设置不会立即应用于视图

Question

I'm creating a ImageView programmatically :

   LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(50,50);
   lp.setMargins(4,4,4,4);

   ImageView color = new ImageView(this);
   color.setLayoutParams(lp);
   colorPicker.addView(color); //adding view to linearlayout
   Log.i("X", "" + color.getX());
   ...

im trying to retrieve color's x poistion via color.getX() , but for some reason it returns 0 instead of 4 meaning its not taking the margin into account

also after doing some search in the docs i found requestLayout() might solve this, but it doesnt help either

public void setMargins (int left, int top, int right, int bottom)

Sets the margins, in pixels. A call to requestLayout() needs to be done so that the new margins are taken into account. Left and right margins may be overriden by requestLayout() depending on layout direction.

UPDATE

if i call color.getX() inside onClick listener it returns 4 as expected

Answer 1

The width , height , margins , etc. of a View aren't applied inmediately, you need to wait for the UI to be sized and laid out on the screen.

getWidth() returns 0 if set by android:layout_width="match_parent"

Try this:

ViewTreeObserver vto = color.getViewTreeObserver(); 
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() { 
    @Override 
    public void onGlobalLayout() { 
        this.layout.getViewTreeObserver().removeGlobalOnLayoutListener(this); 
        Log.i("X", "" + color.getX());

    } 
});

You will need to make "color" variable final or global to be able to access it inside the listener .