Banner屏幕适配

//   502/185f为网络图片的宽高比

float ratio=502/185f;

//banner为Banner的id

ViewGroup.LayoutParams layoutParams = banner.getLayoutParams();
 layoutParams.width = getResources().getDisplayMetrics().widthPixels;
layoutParams.height= (int) (layoutParams.width/ratio);
 banner.setLayoutParams(layoutParams);