android通过代码获取布局的宽高

思想，先测量，执行measure(0, 0);，然后获取getMeasuredHeight();

ll_refrashHeadViewRoot = (LinearLayout) mRootHeadView.findViewById(R.id.ll_refreshhead_root);
        
        //获取下拉刷新头的高度
        ll_refrashHeadViewRoot.measure(0, 0);
        mRefrashHeadViewHeight = ll_refrashHeadViewRoot.getMeasuredHeight();