Android Downloading File by Showing Progress Bar

When our application does a task that takes a considerable amount of time, it is common sense to show the progress of the task to the user.
This is a good User Experience practice. In this tutorial i will be discussing the implementation of a process-progress dialog.

As an example, i am displaying a progress bar that runs while the app downloads an image from the web. You can download any type of file by using tis code ex.(pdf,png).
You have to change file_url value and in java file sdcard path e.g.(downloadedfile.png).

1) Create a new project and fill all the details. File ⇒ New ⇒ Android Project

2) Main.xml

<?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" >

<!-- Download Button -->
<Button android:id="@+id/btnProgressBar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Download File with Progress Bar"
android:layout_marginTop="50dip"/>

<!-- Image view to show image after downloading -->
<ImageView android:id="@+id/my_image"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>

</LinearLayout>

3) MainActivity.java

package com.example.w2class;

import java.io.BufferedInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;

import android.app.Activity;
import android.app.Dialog;
import android.app.ProgressDialog;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class AndroidDownloadFileByProgressBarActivity extends Activity {

// button to show progress dialog
Button btnShowProgress;

// Progress Dialog
private ProgressDialog pDialog;
ImageView my_image;
// Progress dialog type (0 - for Horizontal progress bar)
public static final int progress_bar_type = 0;

// File url to download
private static String file_url = "http://www.w2class.com/wp-content/uploads/2015/08/logo111.png";

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

// show progress bar button
btnShowProgress = (Button) findViewById(R.id.btnProgressBar);
// Image view to show image after downloading
my_image = (ImageView) findViewById(R.id.my_image);
/**
* Show Progress bar click event
* */
btnShowProgress.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
// starting new Async Task
new DownloadFileFromURL().execute(file_url);
}
});
}

/**
* Showing Dialog
* */
@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case progress_bar_type: // we set this to 0
pDialog = new ProgressDialog(this);
pDialog.setMessage("Downloading file. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setMax(100);
pDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
pDialog.setCancelable(true);
pDialog.show();
return pDialog;
default:
return null;
}
}

/**
* Background Async Task to download file
* */
class DownloadFileFromURL extends AsyncTask<String, String, String> {

/**
* Before starting background thread
* Show Progress Bar Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
showDialog(progress_bar_type);
}

/**
* Downloading file in background thread
* */
@Override
protected String doInBackground(String... f_url) {
int count;
try {
URL url = new URL(f_url[0]);
URLConnection conection = url.openConnection();
conection.connect();
// this will be useful so that you can show a tipical 0-100% progress bar
int lenghtOfFile = conection.getContentLength();

// download the file
InputStream input = new BufferedInputStream(url.openStream(), 8192);

// Output stream
OutputStream output = new FileOutputStream("/sdcard/downloadedfile.png");

byte data[] = new byte[1024];

long total = 0;

while ((count = input.read(data)) != -1) {
total += count;
// publishing the progress....
// After this onProgressUpdate will be called
publishProgress(""+(int)((total*100)/lenghtOfFile));

// writing data to file
output.write(data, 0, count);
}

// flushing output
output.flush();

// closing streams
output.close();
input.close();

} catch (Exception e) {
Log.e("Error: ", e.getMessage());
}

return null;
}

/**
* Updating progress bar
* */
protected void onProgressUpdate(String... progress) {
// setting progress percentage
pDialog.setProgress(Integer.parseInt(progress[0]));
}

/**
* After completing background task
* Dismiss the progress dialog
* **/
@Override
protected void onPostExecute(String file_url) {
// dismiss the dialog after the file was downloaded
dismissDialog(progress_bar_type);
// Displaying downloaded image into image view
// Reading image path from sdcard
String imagePath = Environment.getExternalStorageDirectory().toString() + "/downloadedfile.jpg";
// setting downloaded into image view
my_image.setImageDrawable(Drawable.createFromPath(imagePath));

}

}
}

4)  AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.w2class"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk android:minSdkVersion="8" />

<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".AndroidDownloadFileByProgressBarActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

<!-- Permission: Allow Connect to Internet -->
<uses-permission android:name="android.permission.INTERNET" />
<!-- Permission: Writing to SDCard -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

</manifest>