Android开发控件尺寸的测量

我们经常遇到控件得到的宽高为0，因为控件在绘制之前宽高是没有被计算的，

所以需要提前测量。

//------------------------------------------------方法一

int w = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED); int h = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED); imageView.measure(w, h); int height =imageView.getMeasuredHeight(); int width =imageView.getMeasuredWidth(); textView.append("\n"+height+","+width); //-----------------------------------------------方法二 ViewTreeObserver vto = imageView.getViewTreeObserver(); vto.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {   public boolean onPreDraw() {     int height = imageView.getMeasuredHeight();     int width = imageView.getMeasuredWidth();     textView.append("\n"+height+","+width);     return true;   } }); //-----------------------------------------------方法三 ViewTreeObserver vto2 = imageView.getViewTreeObserver(); vto2.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {   @Override   public void onGlobalLayout() {     imageView.getViewTreeObserver().removeGlobalOnLayoutListener(this);     textView.append("\n\n"+imageView.getHeight()+","+imageView.getWidth());   } });