Implement a SeekBar to control the volume of Video Player

Modify the former exercise "Play 3gp video file using MediaPlayer" to add a SeekBar to control the volume.



In order to create a volume control using SeekBar, we have to know the maximum volume and current volume. It can be retrieved using the method audioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC) and audioManager.getStreamVolume(AudioManager.STREAM_MUSIC). And we can change the volume when SeekBar changed, using the method audioManager.setStreamVolume(AudioManager.STREAM_MUSIC, volume index, flags).

Firstly, modify main.xml to add a SeekBar as Volume Control.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 >
<TextView
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 android:text="@string/hello"
 />
<LinearLayout
 android:orientation="horizontal"
 android:layout_height="wrap_content"
 android:layout_width="fill_parent"
 >
<Button
 android:id="@+id/playvideoplayer"
 android:layout_width="0dip"
 android:layout_height="wrap_content"
 android:layout_weight="1"
 android:text="- PLAY Video -"
 />
<Button
 android:id="@+id/pausevideoplayer"
 android:layout_width="0dip"
 android:layout_height="wrap_content"
 android:layout_weight="1"
 android:text="- PAUSE Video -"
 />
</LinearLayout>
<SeekBar
 android:id="@+id/volbar"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 android:layout_margin="10px"
 />
<SurfaceView
 android:id="@+id/surfaceview"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 />
</LinearLayout>

Modify AndroidVideoPlayer to handle the SeekBar as Volume Control.

package com.exercise.AndroidVideoPlayer;

import java.io.IOException;

import android.app.Activity;
import android.content.Context;
import android.graphics.PixelFormat;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;

public class AndroidVideoPlayer extends Activity implements SurfaceHolder.Callback{

MediaPlayer mediaPlayer;
SurfaceView surfaceView;
SurfaceHolder surfaceHolder;
boolean pausing = false;

AudioManager audioManager;

String stringPath = "/sdcard/samplevideo.3gp";

 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.main);
  
  
     audioManager = (AudioManager)getSystemService(Context.AUDIO_SERVICE);
     int maxVolume = audioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);
     int curVolume = audioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
     SeekBar volControl = (SeekBar)findViewById(R.id.volbar);
     volControl.setMax(maxVolume);
     volControl.setProgress(curVolume);
     volControl.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {

 @Override
 public void onStopTrackingTouch(SeekBar arg0) {
  // TODO Auto-generated method stub

 }

 @Override
 public void onStartTrackingTouch(SeekBar arg0) {
  // TODO Auto-generated method stub

 }

 @Override
 public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {
  // TODO Auto-generated method stub
  audioManager.setStreamVolume(AudioManager.STREAM_MUSIC, arg1, 0);
 }
});
  
  
     Button buttonPlayVideo = (Button)findViewById(R.id.playvideoplayer);
     Button buttonPauseVideo = (Button)findViewById(R.id.pausevideoplayer);
  
     getWindow().setFormat(PixelFormat.UNKNOWN);
     surfaceView = (SurfaceView)findViewById(R.id.surfaceview);
     surfaceHolder = surfaceView.getHolder();
     surfaceHolder.addCallback(this);
     surfaceHolder.setFixedSize(176, 144);
     surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
     mediaPlayer = new MediaPlayer();
  
     buttonPlayVideo.setOnClickListener(new Button.OnClickListener(){

 @Override
 public void onClick(View v) {
  // TODO Auto-generated method stub
  pausing = false;

  if(mediaPlayer.isPlaying()){
   mediaPlayer.reset();
  }

  mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
  mediaPlayer.setDisplay(surfaceHolder);

  try {
   mediaPlayer.setDataSource(stringPath);
   mediaPlayer.prepare();
  } catch (IllegalArgumentException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IllegalStateException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }

  mediaPlayer.start();


 }});
  
     buttonPauseVideo.setOnClickListener(new Button.OnClickListener(){

 @Override
 public void onClick(View v) {
  // TODO Auto-generated method stub
  if(pausing){
   pausing = false;
   mediaPlayer.start();
  }
  else{
   pausing = true;
   mediaPlayer.pause();
  }
 }});
  
 }



@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
 int height) {
// TODO Auto-generated method stub

}

@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub

}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub

}
}

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