BGABanner实现图片自适应屏幕宽度且保持原有图片比例－方法1

 @Override
 public void fillBannerItem(final BGABanner banner, final ImageView itemView, String model, int position) {
 Glide.with(context)
 .load(model)
 .placeholder(R.mipmap.banner_holder)
 .listener(new RequestListener() {
 @Override
 public boolean onException(Exception e, String model, Target target, boolean isFirstResource) {
 return false;
 }
 @Override
 public boolean onResourceReady(GlideDrawable resource, String model, Target target, boolean isFromMemoryCache, boolean isFirstResource) {
 if (itemView == null) {
 return false;
 }
 if (itemView.getScaleType() != ImageView.ScaleType.FIT_XY) {
 itemView.setScaleType(ImageView.ScaleType.FIT_XY);
 }
 ViewGroup.LayoutParams params = itemView.getLayoutParams();
 
 
int vw = itemView.getWidth() - itemView.getPaddingLeft() - itemView.getPaddingRight();
 float scale = (float) vw / (float) resource.getIntrinsicWidth();
 int vh = Math.round(resource.getIntrinsicHeight() * scale);
 params.height = vh + itemView.getPaddingTop() + itemView.getPaddingBottom();
 System.out.println("image height:" + params.height);
 System.out.println("image width:" + params.width);
 itemView.setLayoutParams(params);
 ViewGroup.LayoutParams banner_params = banner.getLayoutParams();
 banner_params.width = params.width;
 banner_params.height = params.height;
 banner.setLayoutParams(banner_params);
 return false;
 }
 })
 .into(itemView);
 }
 

上面使用了读取网络图片尺寸的方式实现，缺点就是还没加载完图片时BGABanner的尺寸还没有自适应。

第二个方式：