Android progress bar example

In Android, progress bar is useful to tell user that the task is takes longer time to finish.

In this tutorial, we show you how to display a progress bar dialog to tell user that your task is running, and also how to increase the progress bar status until the task is completed.

Note
Refer to this Android ProgressBar JavaDoc for detail explanation.

P.S This project is developed in Eclipse 3.7, and tested with Android 2.3.3.

1. Add a Button

Open “res/layout/main.xml” file, just add normal button for demonstration.

File : res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
 
    <Button
        android:id="@+id/btnStartProgress"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Download File" />
 
</LinearLayout>

2. Code Code

The key to use progress bar is using “Thread” to run your time consume task and another “Thread” to update the progress bar status accordingly. Read the code’s comment, it should be self-explanatory.

File : MyAndroidAppActivity.java

package com.mkyong.android;
 
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.os.Handler;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
 
public class MyAndroidAppActivity extends Activity {
 
	Button btnStartProgress;
	ProgressDialog progressBar;
	private int progressBarStatus = 0;
	private Handler progressBarHandler = new Handler();
 
	private long fileSize = 0;
 
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
 
		addListenerOnButton();
 
	}
 
	public void addListenerOnButton() {
 
		btnStartProgress = (Button) findViewById(R.id.btnStartProgress);
		btnStartProgress.setOnClickListener(
                 new OnClickListener() {
 
		   @Override
		   public void onClick(View v) {
 
			// prepare for a progress bar dialog
			progressBar = new ProgressDialog(v.getContext());
			progressBar.setCancelable(true);
			progressBar.setMessage("File downloading ...");
			progressBar.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
			progressBar.setProgress(0);
			progressBar.setMax(100);
			progressBar.show();
 
			//reset progress bar status
			progressBarStatus = 0;
 
			//reset filesize
			fileSize = 0;
 
			new Thread(new Runnable() {
			  public void run() {
				while (progressBarStatus < 100) {
 
				  // process some tasks
				  progressBarStatus = doSomeTasks();
 
				  // your computer is too fast, sleep 1 second
				  try {
					Thread.sleep(1000);
				  } catch (InterruptedException e) {
					e.printStackTrace();
				  }
 
				  // Update the progress bar
				  progressBarHandler.post(new Runnable() {
					public void run() {
					  progressBar.setProgress(progressBarStatus);
					}
				  });
				}
 
				// ok, file is downloaded,
				if (progressBarStatus >= 100) {
 
					// sleep 2 seconds, so that you can see the 100%
					try {
						Thread.sleep(2000);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
 
					// close the progress bar dialog
					progressBar.dismiss();
				}
			  }
		       }).start();
 
	           }
 
                });
 
        }
 
	// file download simulator... a really simple
	public int doSomeTasks() {
 
		while (fileSize <= 1000000) {
 
			fileSize++;
 
			if (fileSize == 100000) {
				return 10;
			} else if (fileSize == 200000) {
				return 20;
			} else if (fileSize == 300000) {
				return 30;
			}
			// ...add your own
 
		}
 
		return 100;
 
	}
 
}