Android在onCreate()中获得控件尺寸_android 获取 layout 大小 oncreate-优快云博客

本文介绍了三种在Android应用中测量ImageView宽度和高度的方法。方法一通过直接调用measure方法获取；方法二是利用ViewTreeObserver的addOnPreDrawListener监听器在onPreDraw事件中获取；方法三是使用addOnGlobalLayoutListener监听器在全局布局完成后获取。这些技巧有助于开发者更好地控制和响应视图的变化。

 
        @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

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        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（亲测可用！在onStart（）方法中调用）

 
        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()); 
      
       }   
      
       });