ListView异步下载图像Android中的图像设置不正确

Posted 2023-05-07

【中文标题】ListView异步下载图像Android中的图像设置不正确

【英文标题】：Incorrect Image setting in ListView asynchronous download image Android

【发布时间】：2015-12-04 12:02:48

【问题描述】：

我正在为我的项目做一个 POC，其中员工详细信息（例如姓名、职位、薪水以及他/她的图像）将显示在 ListView android 中。

正在从数据库中获取完整的员工数据。 PFB员工BO：

public class Employeeimplements Parcelable, Serializable 

    @com.google.gson.annotations.SerializedName("id")
    private String id;

    @com.google.gson.annotations.SerializedName("name")
    private String name;

    @com.google.gson.annotations.SerializedName("position")
    private String position;

    @com.google.gson.annotations.SerializedName("displayUrl")
    private String displayUrl;

   // Getter, Setter and Parcelable method implementation.

注意：每个员工都有不同的图片网址。我正在使用的 PFB 代码 sn-p：

loadEmplyeeData() 
    // Lines of code to fetch List of employee from database.

    // If fetched successful then broadcasting that ready to update view.

    Intent broadcast = new Intent();
    broadcast.setAction("employeedata.loaded");
    sendBroadcast(broadcast);

Braodcast 的 onReceive 我正在向 Adapter 设置数据：

// Other line of code

setListAdapter(new ListEmployeeAdapter());

ListAdapter 是：

private class ListEmployeeAdapterextends BaseAdapter 

    List<Employee> empList = this.employees;

    @Override
    public int getCount() 
        return empList .size();
    

    @Override
    public Employee getItem(int arg0) 
        return empList .get(arg0);
    

    @Override
    public long getItemId(int arg0) 
        return arg0;
    

    @SuppressLint("InflateParams")
    public View getView(int position, View convertView, ViewGroup parent) 
        final ViewHolder holder;
        if (convertView == null) 
            LayoutInflater inflater = (LayoutInflater) ListAidActivity.this
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.listitem, null);
            holder = new ViewHolder();
            holder.empName = (TextView) convertView.findViewById(R.id.textView1);
            holder.empPosition =  (TextView) convertView.findViewById(R.id.textView2);
            holder.empName.setTypeface(myTypeface);
            holder.empPosition.setTypeface(myTypeface);

            holder.imageView = (ImageView) convertView.findViewById(R.id.lstImage);
            convertView.setTag(holder);
         else 
            holder = (ViewHolder) convertView.getTag();
        

        Employee emp = (Employee) empList.get(position);

        holder.empName.setText(emp.getName());
        holder.empPosition.setText(emp.getPosition());

        if (holder.imageView != null && !CommonUtils.isEmpty(emp.getDisplayUrl())) 
             new DownloadImageTask((ImageView)holder.imageView).execute(emp.getDisplayUrl());
        

        return convertView;
    

    public Employee getMyEmplyeeItem(int position) 
        return empList.get(position);
    

    class ViewHolder 
        TextView empName;
        TextView empPosition;
        ImageView imageView;
    

PFB 下载图像异步任务：

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> 

    ImageView bmImage;

    public DownloadImageTask(ImageView bmImage) 
        this.bmImage = bmImage;
    

    protected Bitmap doInBackground(String... urls) 
        String urldisplay = urls[0];
        HttpURLConnection urlConnection = null;
        Bitmap mIcon11 = null;
        try 
            if (urldisplay == null) 
                return null;
             else 
                URL uri = new URL(urldisplay);
                urlConnection = (HttpURLConnection) uri.openConnection();
                int statusCode = urlConnection.getResponseCode();
                if (statusCode != HttpStatus.SC_OK) 
                    return null;
                
                if (urlConnection != null) 
                    InputStream in = urlConnection.getInputStream();
                    if (in != null) 
                        mIcon11 = BitmapFactory.decodeStream(in);
                        return mIcon11;
                     else 
                        return null;
                    
                 else 
                    return null;
                
            

         catch (Exception e) 
            if (urlConnection != null) 
                urlConnection.disconnect();
            
            Log.e("", e.getLocalizedMessage());
         finally 
            if (urlConnection != null) 
                urlConnection.disconnect();
            
        
        return mIcon11;
    

    protected void onPostExecute(Bitmap result) 
        if (result != null) 
            bmImage.setImageBitmap(result);
         else 
            Drawable placeholder = bmImage.getContext().getResources().getDrawable(R.drawable.default_img);
            bmImage.setImageDrawable(placeholder);
        
        bmImage.setScaleType(ScaleType.FIT_XY);

    

请提出任何解决方案，因为图像设置不正确@image view。确切地说，员工图片显示在列表视图的随机位置。

【问题讨论】：

有人可以帮忙吗？

【参考方案1】：

为什么要下载图片？ 使用 UrlImageviewHelper 库。 [https://github.com/koush/UrlImageViewHelper][1]

【讨论】：

因为这些图像放置在我的服务器位置，需要使用 DownloadImageTask 下载，无需任何第三方库/第三方代码。

【参考方案2】：

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> 

    ImageView bmImage;

    public DownloadImageTask(ImageView bmImage) 
        this.bmImage = bmImage;
    

    protected Bitmap doInBackground(String... urls) 
        String urldisplay = urls[0];
        HttpURLConnection urlConnection = null;
        Bitmap mIcon11 = null;
    Thread thread = new Thread(new Runnable() 
            @Override
            public void run() 
                  try 
            if (urldisplay == null) 
                return null;
             else 
                URL uri = new URL(urldisplay);
                urlConnection = (HttpURLConnection) uri.openConnection();
                int statusCode = urlConnection.getResponseCode();
                if (statusCode != HttpStatus.SC_OK) 
                    return null;
                
                if (urlConnection != null) 
                    InputStream in = urlConnection.getInputStream();
                    if (in != null) 
                        mIcon11 = BitmapFactory.decodeStream(in);
                        return mIcon11;
                     else 
                        return null;
                    
                 else 
                    return null;
                
            

         catch (Exception e) 
            if (urlConnection != null) 
                urlConnection.disconnect();
            
            Log.e("", e.getLocalizedMessage());
         finally 
            if (urlConnection != null) 
                urlConnection.disconnect();
            
        
            
        );
        thread.start();




        return mIcon11;
    

    protected void onPostExecute(Bitmap result) 
        if (result != null) 
            bmImage.setImageBitmap(result);
         else 
            Drawable placeholder = bmImage.getContext().getResources().getDrawable(R.drawable.default_img);
            bmImage.setImageDrawable(placeholder);
        
        bmImage.setScaleType(ScaleType.FIT_XY);

    

【讨论】：

感谢修改代码。我会检查相同的，让你知道。再次感谢！！！

不工作...总是从 doinbackground 返回位图为空