Activity中获取view的高度和宽度方法

来源:互联网 发布:2017最新网络综艺节目 编辑:程序博客网 时间:2024/05/17 03:48

本文载自 : http://blog.csdn.net/nailsoul/article/details/25909313

在activity中可以调用View.getWidth()、View.getHeight()、View.getMeasuredWidth() 、View.getgetMeasuredHeight()来获得某个view的宽度或高度。
但是在onCreate()、onStrart()、onResume()方法中会返回0,这是应为当前activity所
代表的界面还没显示出来没有添加到WindowPhone的DecorView上或要获取的view没
有被添加到DecorView上或者该View的visibility属性为gone 或者该view的width或height真的为0
所以只有上述条件都不成立时才能得到非0的width和height

要获取到的width和height为真实有效的有一下几种方法

  • 在该View的事件回调里使用 这时候该view已经被显示即被添加到DecorView上 如点击事件 触摸事件 焦点事件等
    View view=findViewById(R.id.tv);          view.setOnClickListener(new OnClickListener() {              @Override              public void onClick(View v) {                  int width = v.getWidth();              }          });  
  • 在activity被显示出来时即添加到了DecorView上时获取宽和高如onWindowFocusChanged() 回调方法
    @Override  public void onWindowFocusChanged(boolean hasFocus) {          View iv1 = findViewById(R.id.iv1);          View iv2=findViewById(R.id.iv2);          String msg1="iv1' width:"+iv1.getWidth()+" height:"+iv1.getHeight();        String msg2="iv2' width:"+iv2.getWidth()+" height:"+iv2.getHeight();    System.out.println(msg1);    System.out.println(msg2);        super.onWindowFocusChanged(hasFocus);        }  
  • 或在onResume方法最后开线程300毫秒左右后获取宽和高 因为onResume执行完后300毫秒后 界面就显示出来了
    view.postDelayed(new Runnable() {                  @Override                  public void run() {                      View iv1 = findViewById(R.id.iv1);                      View iv2=findViewById(R.id.iv2);                      String msg1="iv1' width:"+iv1.getWidth()+" height:"+iv1.getHeight()+"  measuredWidth:"+iv1.getMeasuredWidth()+"measuredHeight:"+iv1.getMeasuredHeight();                      String msg2="iv2' width:"+iv2.getWidth()+" height:"+iv2.getHeight()+"  measuredWidth:"+iv2.getMeasuredWidth()+"measuredHeight:"+iv2.getMeasuredHeight();                      i("onWindowFocusChanged() "+msg1);                      i("onWindowFocusChanged() "+msg2);                  }              }, 300);  
  • 4.在onCreate()或onResume()等方法中需要获取宽高时使用getViewTreeObserver().addOnGlobalLayoutListener()来添为view加回调在回调里获得宽度或者高度获取完后让view删除该回调
    view.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {              @Override              public void onGlobalLayout() {                  view.postDelayed(new Runnable() {                      @Override                      public void run() {                          View iv1 = findViewById(R.id.iv1);                          View iv2=findViewById(R.id.iv2);                          String msg1="iv1' width:"+iv1.getWidth()+" height:"+iv1.getHeight()+"  measuredWidth:"+iv1.getMeasuredWidth()+"measuredHeight:"+iv1.getMeasuredHeight();                          String msg2="iv2' width:"+iv2.getWidth()+" height:"+iv2.getHeight()+"  measuredWidth:"+iv2.getMeasuredWidth()+"measuredHeight:"+iv2.getMeasuredHeight();                          i("onWindowFocusChanged() "+msg1);                          i("onWindowFocusChanged() "+msg2);                      }                  }, 300);              }          });  
  • 在窗口焦点发生变化时获取宽高 onResume完后就会把界面渲染到窗口上 渲染完后将执行窗口焦点花生变化回调 所以onResume到 onWindowFocusChanged为把界面渲染到窗口的时间
boolean measure;      View iv1;      View iv2;      @Override      public void onWindowFocusChanged(boolean hasFocus) {          super.onWindowFocusChanged(hasFocus);          if(hasFocus && !measure){              measure=true;              measure();          }      }      private void findViews(){          iv1 = findViewById(R.id.iv1);          iv2 =findViewById(R.id.iv2);      }      private void measure(){          String msg1="iv1' width:"+iv1.getWidth()+" height:"+iv1.getHeight();        String msg2="iv2' width:"+iv2.getWidth()+" height:"+iv2.getHeight();    }
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