Android getWidth() return 0 in View's onDraw

Question

Here is my code:

    if (myView == null) {
        myView = new View(mContext) {
            @Override
            protected void onDraw(final Canvas canvas) {
                super.onDraw(canvas);
                final float width = (float)getWidth();
                ......
            }
        };

        addView(myView);
    }

    requestLayout();

The width in my code is always 0 although the size of the mContext is not zero. Can anybody advise what could be the possible reason I got 0 for width? Thanks

Please check this link - http://stackoverflow.com/questions/2159320/how-to-size-an-android-view-based-on-its-parents-dimensions — Mel, Feb 24 '15 at 15:58

score 3 · Accepted Answer · answered Feb 24 '15 at 15:56

3

You have to record the dimensions of the canvas in the onSizeChanged handler and then use them in the onDraw handler.

private int canvasWidth;
private int canvasHeight;

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
    canvasWidth = w;
    canvasHeight = h;
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    final float width = (float)canvasWidth;
    ...
}

answered Feb 24 '15 at 15:56

Rob Meeuwisse

2,847
1
17
21

Thanks, I'll have a try. – Bagusflyer Feb 24 '15 at 16:06
I accept your answer is not because it solved my issue. It's because I appreciate your suggestion. Thanks – Bagusflyer Feb 27 '15 at 00:58

score -1 · Answer 2 · answered Feb 24 '15 at 19:18

-1

Being a rookie I think your new view is blank thats y its width and height is coming 0. May b u should try to set its layoutparameter giving some hardcode height and width.

Currently onmeasure has nothing to measure. May B . :P

answered Feb 24 '15 at 19:18

Neeraj Mishra

1
1

Android getWidth() return 0 in View's onDraw

2 Answers2

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