保持view宽高比，实现屏幕自适应

注意：在调用getLayoutParams（）方法时，这个layoutparams的类型，取决于它的父view，如果父view是FrameLayout，那么就是FrameLayout.LayoutParams ,如果是RelativeLayout，那么就是RelativeLayout.LayoutParams。。。其他的如LinearLayout也一样

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);