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android中view的宽高测量

2024-10-27 13:05:39   210人阅读

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一般的，view测量的方法：

@Override 
  public void onCreate(Bundle savedInstanceState) { 
      super.onCreate(savedInstanceState); 
      setContentView(R.layout.main); 
      final ImageView imageView = (ImageView) findViewById(R.id.imageview);       
      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);
      System.out.println("执行完毕.."+System.currentTimeMillis()); 
  }
//------------------------------------------------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()); 
    }   
}); 


最近由于要做自定义view，需要测量view宽高，发现一个不错的api：

View.MeasureSpec.makeMeasureSpec(int,int)

参数1是一个数值，基于该数值计算

参数2是一个mode，指测量的方式，mode如下：

它有三种模式： 
①、UNSPECIFIED(未指定)，父元素部队自元素施加任何束缚，子元素可以得到任意想要的大小； 
②、EXACTLY(完全)，父元素决定自元素的确切大小，子元素将被限定在给定的边界里而忽略它本身大小； 
③、AT_MOST(至多)，子元素至多达到指定大小的值。


具体使用如下:

		int w = View.MeasureSpec.makeMeasureSpec(SCREEN_W,View.MeasureSpec.AT_MOST); 
		int h = View.MeasureSpec.makeMeasureSpec(SCREEN_H/2,View.MeasureSpec.AT_MOST); 
		view.measure(w, h);
		LogUtil.showlog("w:" + w + ",h:" + h);

  1. int w = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED);  
  2. int h = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED);  
  3. textView.measure(w, h);  


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参考：

http://blog.sina.com.cn/s/blog_4172d3d60101h15p.html

http://blog.csdn.net/listening_music/article/details/7210146

http://www.tuicool.com/articles/jiuqEr


android中view的宽高测量


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