How to asynchronously load data in listview?

1 year ago
Olivia Parker
2 minutes

There are two common methods for asynchronously loading data in a ListView: using AsyncTask and using a thread pool.

Use AsyncTask:

  1. Create a class that inherits from AsyncTask and override its doInBackground() method to perform time-consuming operations, such as loading data from the network.
  2. In the doInBackground() method, update the progress using the publishProgress() method.
  3. In the overridden onProgressUpdate() method, update the UI by adding the loaded data to the ListView.
  4. In the overridden onPostExecute() method, update the UI interface, such as displaying a message indicating the completion of loading or showing a message for loading failure.
  5. In the adapter of ListView, implement the method getItem() and getCount() as needed.

Use a thread pool.

  1. Create a thread pool object, such as ExecutorService executor = Executors.newFixedThreadPool(5).
  2. In places where data needs to be loaded asynchronously, submit the task to a thread pool for execution, such as executor.execute(new Runnable() { … }).
  3. Perform time-consuming tasks, such as loading data from the network, in the run() method of the task.
  4. In the run() method, send the loaded data to the UI thread using a Handler, such as handler.sendMessage().
  5. In the UI thread’s Handler, update the UI interface by processing received messages, such as adding loaded data to a ListView.

Whether using AsyncTask or thread pool, it is necessary to update the UI interface during the process of loading data.

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