How to get width and height of resized custom view , before it is drawn

问题

In my custom View .xml , i have defined width and height as w = 600dp , h = 700dp. Now i know getMeasuredHeight() / getMeasuredWidth() give values of width and height after view is drawn and they may differ from what i've given in .xml file , is there a workaround to get getMeasuredHeight() and getMeasuredWidth() values before view is actually drawn on layout, without use of onMeasure() ?

And How to calculate changed dp sizes in different screens ? like my 600h*700w when run on emulator converts to 300*300 .

回答1:

You can override onSizeChanged() to get height and width of the view when it is drawn.refer below:

  @Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    mWidth = w;
    mHeight = h;
    super.onSizeChanged(w, h, oldw, oldh);
    Log.d(TAG, "onSizeChanged: " + " width: " + w + " height: " + h + " oldw " + oldw + " oldh " + oldh);
}

To convert dp into pixels you can use following code:

   sizeInPixels = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
            sizeInDp, getResources().getDisplayMetrics());

来源：https://stackoverflow.com/questions/31548891/how-to-get-width-and-height-of-resized-custom-view-before-it-is-drawn