填充 ListView 的服务中的 AsyncTask

Question

我有这段代码，我将在下面提供。它发布用户 ID、纬度和经度，在 php 中更新当前用户的纬度和经度，然后执行一个查询，检索您周围某个区域内的一组用户。 （检索年龄、姓名..）所以这会填充一个 listView，但必须手动执行查询，通过刷新或打开活动。但是我有一个 LocationService，其中有一个 onLocationChanged()，当用户的位置发生变化时它会更新。每次位置更改时，我都需要执行查询/异步任务，然后在我的 Activity 中填充我的 listView。任何建议/代码示例。

这是我的活动中调用异步任务的代码：

private void startQueryView() {
    // show progress dialog
    dialog = ProgressDialog.show(this, "", "Loading...");

    LocalDatabase localDatabase = new LocalDatabase(this);
    User user = localDatabase.getLoggedInUser();
    String url = ServerRequests.SERVER_ADDRESS + "CombinedQuery.php";
    UserFetchData task = new UserFetchData(this, user.latitude, user.longitude, user.id);
    task.execute(url);
}

@Override
public void onFetchComplete(List<UserQueryData> data) {
    // dismiss the progress dialog
    if (dialog != null) dialog.dismiss();
    // create new adapter
    final UserAdapter adapter = new UserAdapter(this, data);
    listView.setAdapter(adapter);



    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            final int userId = adapter.getItem(position).getId();

            int i;
            new DownloadImage(LocationSearch.this, userId + "_Profile").execute();

            for (i = 2; i < 7; i++) {

                new DownloadImage(LocationSearch.this, userId + "_Image" + Integer.toString(i)).execute();

            }


            ServerRequests serverRequests = new ServerRequests(LocationSearch.this);
            serverRequests.fetchDifUserDataInBackground(userId, new GetDifUserCallback() {
                @Override
                public void done(DifUser returnedDifUser) {

                    if (returnedDifUser == null) {
                        String dir = getFilesDir().getAbsolutePath();
                        File file = new File(dir, userId + "_Profile.JPG");
                        boolean deleted = file.delete();
                        if (deleted) {
                            Log.d("THIS", "******************ProfileDeleted***********");
                        }

                        int i;
                        for (i = 2; i < 7; i++) {
                            String dir2 = getFilesDir().getAbsolutePath();
                            File file2 = new File(dir2, userId + "_Image" + Integer.toString(i) + ".JPG");
                            boolean deleted2 = file2.delete();
                            if (deleted2) {
                                Log.d("THIS", "******************Image" + Integer.toString(i) + "***********");
                            }

                        }

                        Toast.makeText(LocationSearch.this, "Something went wrong!", Toast.LENGTH_SHORT).show();
                    } else {


                        Intent userIdIntent = new Intent(LocationSearch.this, UserProfileOpened.class);
                        SharedPreferences sharedPref = getPreferences(Context.MODE_PRIVATE);
                        SharedPreferences.Editor editor = sharedPref.edit();
                        editor.putInt("userId", userId);
                        editor.commit();
                        userIdIntent.putExtra("userId", userId);
                        userIdIntent.putExtra("name", returnedDifUser.name);
                        userIdIntent.putExtra("city", returnedDifUser.city);
                        userIdIntent.putExtra("age", returnedDifUser.age);
                        userIdIntent.putExtra("gender", returnedDifUser.gender);
                        userIdIntent.putExtra("places", returnedDifUser.places);
                        userIdIntent.putExtra("relationship", returnedDifUser.relationship);
                        userIdIntent.putExtra("facebook", returnedDifUser.facebook);
                        startActivity(userIdIntent);


                    }
                }
            });


        }
    });

}

@Override
public void onFetchFailure(String msg) {
    // dismiss the progress dialog
    if (dialog != null) dialog.dismiss();
    // show failure message
    Toast.makeText(this, msg, Toast.LENGTH_LONG).show();
}

如果您还需要什么，请说出来，我会编辑我的帖子。

Answer 1

编辑：试一试Intents。

像这样进行Intent 操作：

public static String QUERY = "com.package.QUERY";

然后在你的活动中扩展BroadcastReceiver：

private class QueryReceiver extends BroadcastReceiver {
  @Override
  public void OnReceive(Context c, Intent i) {
    startQueryView(); /*running your query when receiving an Intent*/
  }
}

然后在你的活动OnCreate()方法中，设置一个监听器：

IntentFilter filter = new IntentFilter(QUERY);
receiver = new QueryReceiver();
registerReceiver(receiver,filter); /* registering the receiver to receive only intents with the action QUERY */

最后，在位置监听器中，发射Intent：

Intent i = new Intent(QUERY);
sendBroadcast(i);

您应该查看LocationListener 的文档。

http://developer.android.com/reference/android/location/LocationListener.html

使用此功能，您将知道用户的经纬度何时发生变化！