RecyclerView中，图片加载重用问题，异步加载图片

额，首先要感谢这位兄台，然后我就直接上代码吧

解决方式1 demo代码:
public class MyRecyclerAdapter extends RecyclerView.Adapter {
private static final String TAG = "MyRecyclerAdapter";

private List mData;
private Context mContext;
private LayoutInflater inflater;

public MyRecyclerAdapter(Context context, List data) {
this.mContext = context;
this.mData = data;
inflater = LayoutInflater.from(mContext);
}

@Override
public int getItemCount() {
return mData.size();
}

@Override
public void onViewRecycled(MyViewHolder holder) {
super.onViewRecycled(holder);
AsyncTask asyncTask = (AsyncTask) holder.imageView.getTag(1);
asyncTask.cancel(true);
}

@Override
public void onBindViewHolder(final MyViewHolder holder, final int position) {
//先设置图片占位符
holder.imageView.setImageDrawable(mContext.getDrawable(R.mipmap.ic_launcher));
AsyncTask asyncTask = new AsyncTask() {
@Override
protected Bitmap doInBackground(Void... params) {
try {
URL url = new URL(mData.get(position));
Bitmap bitmap = BitmapFactory.decodeStream(url.openStream());
return bitmap;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}

@Override
protected void onPostExecute(Bitmap bitmap) {
super.onPostExecute(bitmap);
holder.imageView.setImageBitmap(bitmap);
}
};
holder.imageView.setTag(1,asyncTask);
asyncTask.execute();
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.item_layout, parent, false);
return new MyViewHolder(view);
}

static class MyViewHolder extends RecyclerView.ViewHolder {

ImageView imageView;

public MyViewHolder(View view) {
super(view);
imageView = (ImageView) view.findViewById(R.id.id_img);
}

}
}
           

或者这样写：

解决方式2 demo代码:
public class MyRecyclerAdapter extends RecyclerView.Adapter {
private static final String TAG = "MyRecyclerAdapter";

private List mData;
private Context mContext;
private LayoutInflater inflater;

public MyRecyclerAdapter(Context context, List data) {
this.mContext = context;
this.mData = data;
inflater = LayoutInflater.from(mContext);
}

@Override
public int getItemCount() {
return mData.size();
}

@Override
public void onViewRecycled(MyViewHolder holder) {
super.onViewRecycled(holder);
}

@Override
public void onBindViewHolder(final MyViewHolder holder, final int position) {
//先设置图片占位符
holder.imageView.setImageDrawable(mContext.getDrawable(R.mipmap.ic_launcher));
final String url = mData.get(position);
//为imageView设置Tag,内容是该imageView等待加载的图片url
holder.imageView.setTag(url);
AsyncTask asyncTask = new AsyncTask() {
@Override
protected Bitmap doInBackground(Void... params) {
try {
URL url = new URL(mData.get(position));
Bitmap bitmap = BitmapFactory.decodeStream(url.openStream());
return bitmap;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}

@Override
protected void onPostExecute(Bitmap bitmap) {
super.onPostExecute(bitmap);
//加载完毕后判断该imageView等待的图片url是不是加载完毕的这张
//如果是则为imageView设置图片,否则说明imageView已经被重用到其他item
if(url.equals(holder.imageView.getTag())) {
holder.imageView.setImageBitmap(bitmap);
}
}
}.execute();
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.item_layout, parent, false);
return new MyViewHolder(view);
}

static class MyViewHolder extends RecyclerView.ViewHolder {

ImageView imageView;

public MyViewHolder(View view) {
super(view);
imageView = (ImageView) view.findViewById(R.id.id_img);
}

}
}
           

ok，完美解决图片异步加载问题。