我正在尝试用缩略图填充我的 Gridview，但我在解码 asynctask 中的图像时遇到问题。当我启动应用程序时，图像被 1 个 1 加载并且图像无法正确显示（一旦我滚动它会显示顶部图像并稍后加载原始图像）。这是我的代码：
public class ImageAdapter extends BaseAdapter {
private Context mContext;
private List<String> mList;
private int mheight;
private int mwidth;
private InputStream is;
public ImageAdapter(Context context, List<String> list, int height, int width) {
mContext = context;
mList = list;
mheight = height;
mwidth = width;
}
@Override
public int getCount() {
return mList.size();
}
@Override
public Object getItem(int position) {
return mList.get(position).toString();
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView;
if (convertView == null) {
imageView = new ImageView(mContext);
} else {
imageView = (ImageView) convertView;
}
InputStream is;
try {
is = mContext.getAssets().open(mList.get(position));
Loadimage task = new Loadimage(imageView , mheight , mwidth);
task.execute(is);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return imageView ;
}
public class Loadimage extends AsyncTask<InputStream, Void, Bitmap>{
private final WeakReference<ImageView> imageViewReference;
private InputStream is = null;
private int width;
public Loadimage(ImageView imageView, int mheight, int mwidth) {
imageViewReference = new WeakReference<ImageView>(imageView);
this.width=mwidth;
// TODO Auto-generated constructor stub
}
@Override
protected Bitmap doInBackground(InputStream... params) {
is = params[0];
if (is !=null) {
Bitmap bitmap = BitmapFactory.decodeStream(is);
Bitmap nBitmap =Bitmap.createScaledBitmap(bitmap,width/3 , width/3, false);
return nBitmap;
}
return null;
}
@Override
protected void onPostExecute(Bitmap bitmap) {
if (imageViewReference != null && bitmap != null) {
final ImageView imageView = imageViewReference.get();
if (imageView != null) {
imageView.setImageBitmap(bitmap);
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
}
}
}
}