android中view的寬高測量

標籤：android

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一般的，view測量的方法：

@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("執行完畢.."+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());     }   }); 

最近由於要做自訂view，需要測量view寬高，發現一個不錯的api：

View.MeasureSpec.makeMeasureSpec(int,int)

參數1是一個數值，基於該數值計算

參數2是一個mode，指測量的方式，mode如下：

它有三種模式： 
①、UNSPECIFIED(未指定)，父元素部隊自元素施加任何束縛，子項目可以得到任意想要的大小； 
②、EXACTLY(完全)，父元素決定自元素的確切大小，子項目將被限定在給定的邊界裡而忽略它本身大小； 
③、AT_MOST(至多)，子項目至多達到指定大小的值。

具體使用如下:

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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參考：

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的寬高測量