Android -- 获取View宽高
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。
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(); } });
onWindowFocusChanged() 回调
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()+" measuredWidth:"+iv1.getMeasuredWidth()+"measuredHeight:"+iv1.getMeasuredHeight(); String msg2="iv2' width:"+iv2.getWidth()+" height:"+iv2.getHeight()+" measuredWidth:"+iv2.getMeasuredWidth()+"measuredHeight:"+iv2.getMeasuredHeight(); Log.i("onWindowFocusChanged() "+msg1); Log.i("onWindowFocusChanged() "+msg2); super.onWindowFocusChanged(hasFocus); }
延时
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(); Log.i("onWindowFocusChanged() "+msg1); Log.i("onWindowFocusChanged() "+msg2); } }, 300);
在onCreate()或onResume()等方法中需要
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(); Log.i("onWindowFocusChanged() "+msg1); Log.i("onWindowFocusChanged() "+msg2); } }, 300); } });
