android获取view宽高的几种方法，解决获取高宽为0问题

在onCreate方法中我们通过mView.getWidth()和mView.getHeight()获取到的view的宽高都是0，那么下面几种方法就可以在onCreate方法中获取到view的宽高。

1、

int w = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
 int h = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
 mTextView.measure(w, h);
 int height = mTextView.getMeasuredHeight();
 int width = mTextView.getMeasuredWidth();
 System.out.println("measure width=" + width + " height=" + height);

2、mViewTreeObserver = mTextView.getViewTreeObserver();

mViewTreeObserver.addOnGlobalLayoutListener(new OnGlobalLayoutListener()
  {
   @Override
   public void onGlobalLayout()
   {
    // TODO Auto-generated method stub
        mTextView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
    System.out.println("onGlobalLayout width=" + mTextView.getWidth() + " height=" + mTextView.getHeight());
   }
  });

3、

mViewTreeObserver.addOnPreDrawListener(new OnPreDrawListener()
  {
   @Override
   public boolean onPreDraw()
   {
    // TODO Auto-generated method stub
        mTextView.getViewTreeObserver().removeOnPreDrawListener(this);
    System.out.println("onPreDraw width=" + mTextView.getWidth() + " height=" + mTextView.getHeight());
    return true;
   }
  });

4、

 @Override
 public void onWindowFocusChanged(boolean hasFocus)
 {
  // TODO Auto-generated method stub
  super.onWindowFocusChanged(hasFocus);
  if (hasFocus)
  {
   System.out.println("onWindowFocusChanged width=" + mTextView.getWidth() + " height=" + mTextView.getHeight());
  }
 }