How To Show A Progress Dialog in Android

OVERVIEW

When you need to do some long running task and show a “wait” dialog to the user while the task is running, a Progress Dialog is the best way to go. When you do not know how long the task will take , then you show a Spinner instead of a horizontal progress bar. Here we will use the example of using a Spinner while authenticating a user after he has filled in a login form.

 

CODE

In our layout xml we called the doLogin() function when the Login button is clicked. This function will in turn execute an AsyncTask which will execute a backend process. The ProgressDialog will be shown before the AsyncTask starts execution and will go away once the AsyncTask has finished execution.

public class LoginActivity extends ActionBarActivity {

    ProgressDialog mProgressBar;

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        mProgressBar = new ProgressDialog(this);
    }

 public void doLogin(View view) {
        mProgressBar.setCancelable(false);
        mProgressBar.setMessage("Authenticating your login..");
        mProgressBar.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        mProgressBar.show();
        new LoginTask().execute(0);

    }
}

  //////////////////////////////////////////////////////////////////////////////

    //
    // The params are dummy and not used
    //
    class LoginTask extends AsyncTask<Integer, Integer, String> {
        @Override
        protected String doInBackground(Integer... params) {

                try {
                    Thread.sleep(2000);
                    // some long running task will run here. We are using sleep as a dummy to delay execution

                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            return "Task Completed.";
        }
        @Override
        protected void onPostExecute(String result) {
            mProgressBar.hide();
            // do whatever needs to be done next
        }
        @Override
        protected void onPreExecute() {
        }
        @Override
        protected void onProgressUpdate(Integer... values) {

        }
    }