如何在列表项点击而不是 UI 线程上进行长时间操作？

Question

我有一个列表视图，其中每个项目包含 3 个按钮，一个用于保存在数据库中，另外两个用于打开新片段。我已经为适配器的 getView() 方法中的哪个按钮实现了 OnClickListener。当用户单击保存按钮时，我想在数据库中写入项目。既然，写入数据库被认为是一个长操作，不应该在UI线程上进行，请问如何进行？我应该创建自己的线程还是可以使用服务或异步任务？这是来自 getView 的代码：

 public View getView(final int position, View convertView, ViewGroup parent) {

    ViewHolder viewHolder;
    if(convertView==null){
        convertView=layoutInflater.inflate(R.layout.top_tracks_artists_item_layout,parent,false);

        viewHolder=new ViewHolder();
        viewHolder.trackName= (TextView) convertView.findViewById(R.id.top_tracks_item_name);

        viewHolder.trackInfo= (Button) convertView.findViewById(R.id.top_tracks_item_info);
        viewHolder.trackInfo.setTag(position);
        viewHolder.trackInfo.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d("try", "Info clicked "  +position);
            }
        });

        viewHolder.trackFavourite= (Button) convertView.findViewById(R.id.top_tracks_item_favourite);
        viewHolder.trackFavourite.setTag(position);
        viewHolder.trackFavourite.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                Log.d("try", "favourites  clicked " +position);
            }
        });

        viewHolder.trackWatch= (Button) convertView.findViewById(R.id.top_tracks_item_watch);
        viewHolder.trackWatch.setTag(position);
        viewHolder.trackWatch.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d("try", "Watch clicked "  +position);
    //here I want to save to database

            }
        });

        convertView.setTag(viewHolder);
    }else{
        viewHolder= (ViewHolder) convertView.getTag();
    }

    viewHolder.trackName.setText((String)tracks.get(position).toString());

    return convertView;
}

提前致谢。

Answer 1

你可以试试AsyncTask，如果你想显示保存进度，也可以考虑在保存图像时显示一个旋转器。一旦你保存到数据库完成发送状态完成并关闭你的进度条。如果您需要一些关于如何操作的示例，请参阅下面 link。

Answer 2

对后台任务使用Android AsyncTask。用法是这样的;

    private class DownloadFilesTask extends AsyncTask<URL, Integer, Long> {
     protected Long doInBackground(URL... urls) {
         int count = urls.length;
         long totalSize = 0;
         for (int i = 0; i < count; i++) {
             totalSize += Downloader.downloadFile(urls[i]);
             publishProgress((int) ((i / (float) count) * 100));
             // Escape early if cancel() is called
             if (isCancelled()) break;
         }
         return totalSize;
     }

     protected void onProgressUpdate(Integer... progress) {
         setProgressPercent(progress[0]);
     }

     protected void onPostExecute(Long result) {
         showDialog("Downloaded " + result + " bytes");
     }
 }

Answer 3

您可以使用异步任务或处理程序来实现。在给定的 link

中查看以下教程和参考资料

http://www.vogella.com/tutorials/AndroidBackgroundProcessing/article.html

Answer 4

服务

Not bounded to the Activity lifecycle , services will run even if your application is closed/switched/Config Changes

Operation to be performed by service Runs in the Main(UI) Thread, So you need to create a Java-Thread inside onStartCommand() method

意向服务

Not bounded to the Activity lifecycle , services will run even if your application is closed/switched/Config Changes

Operation to be performed by IntentService runs in "single worker thread" Note : Since it runs on "single worker thread" thus is not suited for Multithreaded Applications

AsyncTask

Bounded to Activity lifecycle , services will not run if your application is closed/switched/Config Changes,So you need to take these on consideration while using AsyncTask

如何在列表项点击而不是 UI 线程上进行长时间操作？

How to make long operations on list item click but not on UI thread?

sqlite

android

listview-adapter

onclicklistener