保持view寬高比，實現屏幕自適應

注意：在調用getLayoutParams（）方法時，這個layoutparams的類型，取決於它的父view，如果父view是FrameLayout，那麼就是FrameLayout.LayoutParams ,如果是RelativeLayout，那麼就是RelativeLayout.LayoutParams。。。其他的如LinearLayout也一樣

  DisplayMetrics dm = getResources().getDisplayMetrics();
            if (dm != null) {
                screenWidth = dm.widthPixels;
                screenHeight = dm.heightPixels;
            }
            int webviewWidth = (int)(screenWidth * (405.0/375.0));
            int cancelWidth = screenHeight - webviewWidth;
            LinearLayout.LayoutParams cancelParams = (LinearLayout.LayoutParams) mNineBoxCancelView.getLayoutParams();
            cancelParams.width = cancelWidth;
            mNineBoxCancelView.setLayoutParams(cancelParams);
            LinearLayout.LayoutParams webviewParams = (LinearLayout.LayoutParams) mNineBoxWebview.getLayoutParams();
            webviewParams.width = webviewWidth;
            mNineBoxWebview.setLayoutParams(webviewParams);