Android 在 ListVIew 中异步加载 ImageView，图像自动更改且不正确

Question

我有一个 ListView 来显示带有短标题的照片库（ImageView + TexiView）。我使用 AsyncTask 来完成下载任务。但问题是有时它会显示错误的图像然后突然改变（可能会发生很多次）。例如：IA B C 将分别显示在ListView 中，图像m1 m2 m3 分别为ABC。当我运行应用程序时，A 的 imageView 可能会显示 m1、m2 或 m3 并且经常更改。这是我的代码：

下层阶级：

  public class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
    ImageView bmImage = null;

    public DownloadImageTask(ImageView bmImage) {
        this.bmImage = bmImage;
    }
    protected Bitmap doInBackground(String... urls) {
        String urldisplay = urls[0];
        Bitmap mIcon11 = null;
        try {
            InputStream in = new java.net.URL(urldisplay).openStream();
            mIcon11 = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return mIcon11;
    }
    protected void onPostExecute(Bitmap result) {
        if(result == null){
            bmImage.setImageResource(R.drawable.loading);
          }else{
            bmImage.setImageBitmap(result);
            }
    }
}

ListView 的适配器：

    public View getView(int position, View convertView, ViewGroup parent){
    item item1 = getItem(position);
    if (convertView == null) {
        convertView = LayoutInflater.from(getContext()).inflate(R.layout.item1, parent, false);
    }
    ImageView iv = (ImageView) convertView.findViewById(R.id.img);
    TextView ttv = (TextView) convertView.findViewById(R.id.p_title);
    TextView itv = (TextView) convertView.findViewById(R.id.p_price);
    /**
    *Download Image
    */
    String img_url;
    img_url = item1.getImg_url();
    new DownloadImageTask((ImageView) convertView.findViewById(R.id.img))
            .execute(img_url);

    ttv.setText(item1.getTitle());
    itv.setText("$"+item1.getPrice());
    return convertView;
}

Activity:

 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.show_promotion2);

    gridView = (GridView) findViewById(R.id.gridview);
    getPromotionByRequest(previousPage, data);//Get Data for items

    itemAdapter = new promotionAdapter(this, items);
    //progress..........
    gridView.setAdapter(itemAdapter);
    setupListViewListener();
}

Answer 1

尝试使用 viewholder 代替 getview

public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(getActivity());
View view = inflater.inflate(android.R.layout.list_item_recyclerView, parent, false);
return new ViewHolder(view);
}

否则也在getview中尝试这个创建布局充气器：

LayoutInflater  inflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);

并创建另一个视图引用：
然后膨胀子视图：

View v = convertView;
v = mInflater.inflate(R.layout.layout_namehere, parent, false);
TextView name = (TextView) view.findViewById(R.id.name);

Answer 2

public View getView(int position, View convertView, ViewGroup parent){
item item1 = getItem(position);
ViewHolder vh = null;
if (convertView == null) {
    convertView = LayoutInflater.from(getContext()).inflate(R.layout.item1, parent, false);
    vh.iv = (ImageView) convertView.findViewById(R.id.img);
    vh.ttv = (TextView) convertView.findViewById(R.id.p_title);
    vh.itv = (TextView) convertView.findViewById(R.id.p_price);
    convertView.setTag(vh);
}else{
    vh = (ViewHoldler)convertView.getTag();
}

/**
*Download Image
*/
String img_url;
img_url = item1.getImg_url();
new DownloadImageTask((ImageView) convertView.findViewById(R.id.img))
        .execute(img_url);

ttv.setText(item1.getTitle());
itv.setText("$"+item1.getPrice());
return convertView;

}

public class ViewHolder {
  public ImageView iv;
  public TextView ttv;
  public TextView itv;
}

可能不正确，你可以试试...我好久没有listview了

Answer 3

在 getview() 方法中创建视图持有者 class，如下所示。

ViewHolder holder = new ViewHolder();

然后像下面的代码一样向 holder 添加视图

holder.imageviewname= (ImageView) convertView.findViewById(R.id.listitem_image);
holder.textviewname = (TextView) convertView.findViewById(R.id.listitem_text);

有关更多信息，请参阅文档 https://developer.android.com/training/improving-layouts/smooth-scrolling.html

Answer 4

感谢您的回答，不幸的是问题仍然存在。最后，我确实通过在每个适配器中使用"Picasso"解决了它，如此强大

Android 在 ListVIew 中异步加载 ImageView，图像自动更改且不正确

Android Asyn loading ImageView in ListVIew, image changed auto and not correct

android

listview

android-imageview

android-asynctask