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Android Asynctask with Progress Bar

In Android development, it's common to perform tasks in the background to avoid blocking the main UI thread. AsyncTask is a class provided by Android that allows you to do just that. In this article, we will learn how to use AsyncTask with a progress bar to show the progress of a background task.

Overview of AsyncTask

AsyncTask is a generic class in Android that allows you to perform background operations and publish results on the UI thread without having to manipulate threads and handlers directly. It provides methods to execute code in the background, update progress, and post results on the UI thread.

Using AsyncTask with Progress Bar

To use AsyncTask with a progress bar, you need to create a custom AsyncTask class that updates the progress bar while executing the background task. Here's an example of how you can achieve this:

public class MyTask extends AsyncTask<Void, Integer, Void> {

    private ProgressBar progressBar;

    public MyTask(ProgressBar progressBar) {
        this.progressBar = progressBar;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        progressBar.setVisibility(View.VISIBLE);
    }

    @Override
    protected Void doInBackground(Void... voids) {
        for (int i = 0; i < 100; i++) {
            // Simulating a long-running task
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            publishProgress(i);
        }
        return null;
    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        super.onProgressUpdate(values);
        progressBar.setProgress(values[0]);
    }

    @Override
    protected void onPostExecute(Void aVoid) {
        super.onPostExecute(aVoid);
        progressBar.setVisibility(View.GONE);
    }
}

In this code snippet, we create a custom AsyncTask class called MyTask that takes a ProgressBar as a parameter. We override the onPreExecute, doInBackground, onProgressUpdate, and onPostExecute methods to update the progress bar at different stages of the AsyncTask execution.

Flowchart of AsyncTask with Progress Bar

The flowchart below illustrates the flow of using AsyncTask with a progress bar:

flowchart TD
    A[Start] --> B{Task Execution}
    B --> C[Show Progress Bar]
    C --> D[Execute Background Task]
    D --> E{Update Progress}
    E --> F[Update Progress Bar]
    F --> D
    D --> G[Task Completed]
    G --> H[Hide Progress Bar]
    H --> I[End]

State Diagram of AsyncTask with Progress Bar

The state diagram below shows the different states of AsyncTask with a progress bar:

stateDiagram
    [*] --> Ready
    Ready --> Running: Start AsyncTask
    Running --> Finished: Task Completed
    Running --> Running: Update Progress
    Finished --> [*]: End

Conclusion

In this article, we have learned how to use AsyncTask with a progress bar in Android development. By following the example and understanding the flowchart and state diagram, you can implement background tasks with progress updates in your Android apps. AsyncTask provides a convenient way to handle background operations and update the UI thread without blocking the main thread. Experiment with different tasks and progress bar styles to enhance the user experience in your applications.