如何获取到Android控件的高度

        很多人在activity主线程中调用getWidth、getMeasuredWidth，却获取不到view的宽高，这是因为此时view还没有完成绘制，当然获取不到，那要怎么办呢？

        方法一,自己测量：

int w = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED);
int h = View.MeasureSpec.makeMeasureSpec(0,View.MeasureSpec.UNSPECIFIED);
view.measure(w, h);
int height = view.getMeasuredHeight();
int width = vew.getMeasuredWidth();

        方法二，添加绘图监听，绘图结束后获取view的大小：

view.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() { 
            public boolean onPreDraw() { 
                view.getViewTreeObserver().removeOnPreDrawListener(this);
                int height = view.getMeasuredHeight(); 
                int width = view.getMeasuredWidth(); 
                return true; 
            } 
        });

    方法三，添加全局布局变化监听：

view.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() { 
            @Override  
            public void onGlobalLayout() { 
                view.getViewTreeObserver().removeGlobalOnLayoutListener(this); 
                view.getHeight();
                view.getWidth();
            }   
        });