Intent.ACTION_GET_CONTENT to open mp3, play using MediaPlayer, tested on Android 5.1 Lollipop

Refer to my old exercise of MediaPlayer "Display playing time for MediaPlayer", open mp3 using Intent of "ACTION_GET_CONTENT", then pass the media path, data.getData().getPath(), to mediaPlayer.setDataSource(). But it not work now.

To fix it, modify to pass data.getData() to mediaPlayer.setDataSource().

Tested on Android emulator running 5.5 Lollipop:


MainActivity.java

package com.blogspot.android_er.androidplayer;

import android.content.Intent;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;

import java.io.IOException;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class MainActivity extends AppCompatActivity {

    TextView info, state;
    Button buttonOpen, buttonOpenNew;
    Button buttonPlay, buttonPause, buttonStop;
    SeekBar timeLine;
    LinearLayout timeFrame;
    TextView timePos, timeDur;

    final static int RQS_OPEN_AUDIO_MP3 = 1;
    final static int RQS_OPEN_AUDIO_MP3_NEW = 2;

    MediaPlayer mediaPlayer;
    String srcPath = null;

    enum MP_State {
        Idle, Initialized, Prepared, Started, Paused,
        Stopped, PlaybackCompleted, End, Error, Preparing
    }

    MP_State mediaPlayerState;

    //ScheduledExecutorService myScheduledExecutorService;

    /**
     * Called when the activity is first created.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        buttonOpen = (Button) findViewById(R.id.open);
        buttonOpen.setOnClickListener(buttonOpenOnClickListener);
        buttonOpenNew = (Button) findViewById(R.id.opennew);
        buttonOpenNew.setOnClickListener(buttonOpenNewOnClickListener);

        info = (TextView) findViewById(R.id.info);
        state = (TextView) findViewById(R.id.state);

        buttonPlay = (Button) findViewById(R.id.play);
        buttonPlay.setOnClickListener(buttonPlayOnClickListener);
        buttonPause = (Button) findViewById(R.id.pause);
        buttonPause.setOnClickListener(buttonPauseOnClickListener);
        buttonStop = (Button) findViewById(R.id.stop);
        buttonStop.setOnClickListener(buttonStopOnClickListener);

        //
        timeLine = (SeekBar) findViewById(R.id.seekbartimeline);
        timeFrame = (LinearLayout) findViewById(R.id.timeframe);
        timePos = (TextView) findViewById(R.id.pos);
        timeDur = (TextView) findViewById(R.id.dur);

        ScheduledExecutorService myScheduledExecutorService
                = Executors.newScheduledThreadPool(1);

        myScheduledExecutorService.scheduleWithFixedDelay(
                new Runnable() {
                    @Override
                    public void run() {
                        monitorHandler.sendMessage(monitorHandler.obtainMessage());
                    }
                },
                200, //initialDelay
                200, //delay
                TimeUnit.MILLISECONDS);

    }

    Handler monitorHandler = new Handler() {

        @Override
        public void handleMessage(Message msg) {
            mediaPlayerMonitor();
        }

    };

    private void mediaPlayerMonitor() {
        if (mediaPlayer == null) {
            timeLine.setVisibility(View.INVISIBLE);
            timeFrame.setVisibility(View.INVISIBLE);
        } else {
            if (mediaPlayer.isPlaying()) {
                timeLine.setVisibility(View.VISIBLE);
                timeFrame.setVisibility(View.VISIBLE);

                int mediaDuration = mediaPlayer.getDuration();
                int mediaPosition = mediaPlayer.getCurrentPosition();
                timeLine.setMax(mediaDuration);
                timeLine.setProgress(mediaPosition);
                timePos.setText(String.valueOf((float) mediaPosition / 1000) + "s");
                timeDur.setText(String.valueOf((float) mediaDuration / 1000) + "s");
            } else {
                timeLine.setVisibility(View.INVISIBLE);
                timeFrame.setVisibility(View.INVISIBLE);
            }
        }
    }

    MediaPlayer.OnErrorListener mediaPlayerOnErrorListener
            = new MediaPlayer.OnErrorListener() {

        @Override
        public boolean onError(MediaPlayer mp, int what, int extra) {
            // TODO Auto-generated method stub

            mediaPlayerState = MP_State.Error;
            showMediaPlayerState();

            return false;
        }
    };


    private void cmdReset() {
        if (mediaPlayer == null) {
            mediaPlayer = new MediaPlayer();
            mediaPlayer.setOnErrorListener(mediaPlayerOnErrorListener);
        }
        mediaPlayer.reset();
        mediaPlayerState = MP_State.Idle;
        showMediaPlayerState();
    }

    private void cmdSetDataSource(Uri uri) {
        if (mediaPlayerState == MP_State.Idle) {
            try {
                mediaPlayer.setDataSource(MainActivity.this, uri);
                mediaPlayerState = MP_State.Initialized;
            } catch (IllegalArgumentException e) {
                Toast.makeText(MainActivity.this,
                        e.toString(), Toast.LENGTH_LONG).show();
                e.printStackTrace();
            } catch (IllegalStateException e) {
                Toast.makeText(MainActivity.this,
                        e.toString(), Toast.LENGTH_LONG).show();
                e.printStackTrace();
            } catch (IOException e) {
                Toast.makeText(MainActivity.this,
                        e.toString(), Toast.LENGTH_LONG).show();
                e.printStackTrace();
            }
        } else {
            Toast.makeText(MainActivity.this,
                    "Invalid State@cmdSetDataSource - skip",
                    Toast.LENGTH_LONG).show();
        }

        showMediaPlayerState();
    }

    private void cmdSetDataSource(String path) {
        if (mediaPlayerState == MP_State.Idle) {
            try {
                mediaPlayer.setDataSource(path);
                mediaPlayerState = MP_State.Initialized;
            } catch (IllegalArgumentException e) {
                Toast.makeText(MainActivity.this,
                        e.toString(), Toast.LENGTH_LONG).show();
                e.printStackTrace();
            } catch (IllegalStateException e) {
                Toast.makeText(MainActivity.this,
                        e.toString(), Toast.LENGTH_LONG).show();
                e.printStackTrace();
            } catch (IOException e) {
                Toast.makeText(MainActivity.this,
                        e.toString(), Toast.LENGTH_LONG).show();
                e.printStackTrace();
            }
        } else {
            Toast.makeText(MainActivity.this,
                    "Invalid State@cmdSetDataSource - skip",
                    Toast.LENGTH_LONG).show();
        }

        showMediaPlayerState();
    }

    private void cmdPrepare() {

        if (mediaPlayerState == MP_State.Initialized
                || mediaPlayerState == MP_State.Stopped) {
            try {
                mediaPlayer.prepare();
                mediaPlayerState = MP_State.Prepared;
            } catch (IllegalStateException e) {
                Toast.makeText(MainActivity.this,
                        e.toString(), Toast.LENGTH_LONG).show();
                e.printStackTrace();
            } catch (IOException e) {
                Toast.makeText(MainActivity.this,
                        e.toString(), Toast.LENGTH_LONG).show();
                e.printStackTrace();
            }
        } else {
            Toast.makeText(MainActivity.this,
                    "Invalid State@cmdPrepare() - skip",
                    Toast.LENGTH_LONG).show();
        }

        showMediaPlayerState();
    }

    private void cmdStart() {
        if (mediaPlayerState == MP_State.Prepared
                || mediaPlayerState == MP_State.Started
                || mediaPlayerState == MP_State.Paused
                || mediaPlayerState == MP_State.PlaybackCompleted) {
            mediaPlayer.start();
            mediaPlayerState = MP_State.Started;
        } else {
            Toast.makeText(MainActivity.this,
                    "Invalid State@cmdStart() - skip",
                    Toast.LENGTH_LONG).show();
        }

        showMediaPlayerState();
    }

    private void cmdPause() {
        if (mediaPlayerState == MP_State.Started
                || mediaPlayerState == MP_State.Paused) {
            mediaPlayer.pause();
            mediaPlayerState = MP_State.Paused;
        } else {
            Toast.makeText(MainActivity.this,
                    "Invalid State@cmdPause() - skip",
                    Toast.LENGTH_LONG).show();
        }
        showMediaPlayerState();
    }

    private void cmdStop() {

        if (mediaPlayerState == MP_State.Prepared
                || mediaPlayerState == MP_State.Started
                || mediaPlayerState == MP_State.Stopped
                || mediaPlayerState == MP_State.Paused
                || mediaPlayerState == MP_State.PlaybackCompleted) {
            mediaPlayer.stop();
            mediaPlayerState = MP_State.Stopped;
        } else {
            Toast.makeText(MainActivity.this,
                    "Invalid State@cmdStop() - skip",
                    Toast.LENGTH_LONG).show();
        }
        showMediaPlayerState();

    }

    private void showMediaPlayerState() {

        switch (mediaPlayerState) {
            case Idle:
                state.setText("Idle");
                break;
            case Initialized:
                state.setText("Initialized");
                break;
            case Prepared:
                state.setText("Prepared");
                break;
            case Started:
                state.setText("Started");
                break;
            case Paused:
                state.setText("Paused");
                break;
            case Stopped:
                state.setText("Stopped");
                break;
            case PlaybackCompleted:
                state.setText("PlaybackCompleted");
                break;
            case End:
                state.setText("End");
                break;
            case Error:
                state.setText("Error");
                break;
            case Preparing:
                state.setText("Preparing");
                break;
            default:
                state.setText("Unknown!");
        }
    }

    View.OnClickListener buttonPlayOnClickListener
            = new View.OnClickListener() {

        @Override
        public void onClick(View v) {

            if (srcPath == null) {
                Toast.makeText(MainActivity.this,
                        "No file selected",
                        Toast.LENGTH_LONG).show();
            } else {
                cmdPrepare();
                cmdStart();
            }

        }

    };

    View.OnClickListener buttonPauseOnClickListener
            = new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            cmdPause();
        }

    };

    View.OnClickListener buttonStopOnClickListener
            = new View.OnClickListener() {

        @Override
        public void onClick(View v) {

            cmdStop();

        }

    };

    View.OnClickListener buttonOpenOnClickListener
            = new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {
            Intent intent = new Intent();
            intent.setType("audio/mp3");
            intent.setAction(Intent.ACTION_GET_CONTENT);
            startActivityForResult(Intent.createChooser(
                    intent, "Open Audio (mp3) file"), RQS_OPEN_AUDIO_MP3);

        }
    };

    View.OnClickListener buttonOpenNewOnClickListener
            = new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {
            Intent intent = new Intent();
            intent.setType("audio/mp3");
            intent.setAction(Intent.ACTION_GET_CONTENT);
            startActivityForResult(Intent.createChooser(
                    intent, "Open Audio (mp3) file"), RQS_OPEN_AUDIO_MP3_NEW);

        }
    };

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode == RESULT_OK) {
            if (requestCode == RQS_OPEN_AUDIO_MP3) {
//work on my old post at that time, but not work now!!!
//http://android-er.blogspot.com/2012/06/display-playing-time-for-mediaplayer.html
                Uri audioFileUri = data.getData();

                srcPath = audioFileUri.getPath();
                info.setText(audioFileUri.toString() + "\n" + srcPath);

                cmdReset();
                cmdSetDataSource(srcPath);

            }else if(requestCode == RQS_OPEN_AUDIO_MP3_NEW){
                //New version,
                Uri audioFileUri = data.getData();

                srcPath = audioFileUri.getPath();
                info.setText(audioFileUri.toString() + "\n" + srcPath);

                cmdReset();
                cmdSetDataSource(audioFileUri);
            }
        }
    }
}

layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="16dp"
    tools:context="com.blogspot.android_er.androidplayer.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <Button
        android:id="@+id/open"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Open MP3 file" />

    <Button
        android:id="@+id/opennew"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Open MP3 file (NEW)" />

    <TextView
        android:id="@+id/info"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/play"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Play" />

    <Button
        android:id="@+id/pause"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Pause" />

    <Button
        android:id="@+id/stop"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Stop" />

    <TextView
        android:id="@+id/state"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />

    <SeekBar
        android:id="@+id/seekbartimeline"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:visibility="invisible" />

    <LinearLayout
        android:id="@+id/timeframe"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:visibility="invisible">

        <TextView
            android:id="@+id/pos"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />

        <TextView
            android:id="@+id/dur"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="right" />
    </LinearLayout>

</LinearLayout>

uses-permission of "android.permission.READ_EXTERNAL_STORAGE" is needed in AndroidManifest.xml


Download the files .

Related:
- Open mp3 using Intent.ACTION_OPEN_DOCUMENT, ACTION_GET_CONTENT and ACTION_PICK, with checking and requesting permission at runtime.

Add MediaController to MediaPlayer

This example show how to add MediaController to simple MediaPlayer in previous example.


MainActivity.java

package com.blogspot.android_er.androidmediaplayer;

import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.MediaController;
import android.widget.Toast;

import java.io.IOException;

public class MainActivity extends AppCompatActivity
        implements SurfaceHolder.Callback, MediaPlayer.OnPreparedListener,
        MediaController.MediaPlayerControl {

    private SurfaceView surfaceView;
    private SurfaceHolder surfaceHolder;
    private MediaPlayer mediaPlayer;

    private MediaController mediaController;
    private Handler handler = new Handler();

    String videoSource =
            "https://sites.google.com/site/androidexample9/download/RunningClock.mp4";

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

        surfaceView = (SurfaceView)findViewById(R.id.surfaceview);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);

        surfaceView.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if(mediaController != null){
                    mediaController.show();
                }
                return false;
            }
        });

    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {

        Toast.makeText(MainActivity.this,
                "surfaceCreated()", Toast.LENGTH_LONG).show();
        mediaPlayer = new MediaPlayer();
        mediaPlayer.setDisplay(surfaceHolder);
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mediaPlayer.setOnPreparedListener(this);
        try {
            mediaPlayer.setDataSource(videoSource);
            mediaPlayer.prepare();

            mediaController = new MediaController(this);

        } catch (IOException e) {
            e.printStackTrace();
            Toast.makeText(MainActivity.this,
                    "something wrong!\n" + e.toString(),
                    Toast.LENGTH_LONG).show();
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder,
                               int format, int width, int height) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {

    }

    @Override
    public void onPrepared(MediaPlayer mp) {
        mediaPlayer.start();
        Toast.makeText(MainActivity.this,
                "onPrepared()", Toast.LENGTH_LONG).show();

        mediaController.setMediaPlayer(this);
        mediaController.setAnchorView(surfaceView);
        handler.post(new Runnable() {

            public void run() {
                mediaController.setEnabled(true);
                mediaController.show();
            }
        });
    }

    @Override
    public void start() {
        mediaPlayer.start();
    }

    @Override
    public void pause() {
        mediaPlayer.pause();
    }

    @Override
    public int getDuration() {
        return mediaPlayer.getDuration();
    }

    @Override
    public int getCurrentPosition() {
        return mediaPlayer.getCurrentPosition();
    }

    @Override
    public void seekTo(int pos) {
        mediaPlayer.seekTo(pos);
    }

    @Override
    public boolean isPlaying() {
        return mediaPlayer.isPlaying();
    }

    @Override
    public int getBufferPercentage() {
        return 0;
    }

    @Override
    public boolean canPause() {
        return true;
    }

    @Override
    public boolean canSeekBackward() {
        return true;
    }

    @Override
    public boolean canSeekForward() {
        return true;
    }

    @Override
    public int getAudioSessionId() {
        return mediaPlayer.getAudioSessionId();
    }
}

For layout and permission, refer to the previous post "MediaPlayer example to play video from Internet".

MediaPlayer example to play video from Internet

Example using MediaPlayer/SurfaceView example to play video from Internet.

MainActivity.java

package com.blogspot.android_er.androidmediaplayer;

import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.Toast;

import java.io.IOException;

public class MainActivity extends AppCompatActivity
        implements SurfaceHolder.Callback, MediaPlayer.OnPreparedListener {

    private SurfaceView surfaceView;
    private SurfaceHolder surfaceHolder;
    private MediaPlayer mediaPlayer;

    String videoSource =
            "https://sites.google.com/site/androidexample9/download/RunningClock.mp4";

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

        surfaceView = (SurfaceView)findViewById(R.id.surfaceview);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {

        Toast.makeText(MainActivity.this,
                "surfaceCreated()", Toast.LENGTH_LONG).show();
        mediaPlayer = new MediaPlayer();
        mediaPlayer.setDisplay(surfaceHolder);
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mediaPlayer.setOnPreparedListener(this);
        try {
            mediaPlayer.setDataSource(videoSource);
            mediaPlayer.prepare();
        } catch (IOException e) {
            e.printStackTrace();
            Toast.makeText(MainActivity.this,
                    "something wrong!\n" + e.toString(),
                    Toast.LENGTH_LONG).show();
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder,
                               int format, int width, int height) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {

    }

    @Override
    public void onPrepared(MediaPlayer mp) {
        mediaPlayer.start();
        Toast.makeText(MainActivity.this,
                "onPrepared()", Toast.LENGTH_LONG).show();
    }
}

layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidmediaplayer.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />

    <SurfaceView
        android:id="@+id/surfaceview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

uses-permission of "android.permission.INTERNET" is needed in AndroidManifest.xml.

---

Next:
- Add MediaController to MediaPlayer

Related:
- VideoView example to play video from Internet

Create audio Visualizer for MediaPlayer

This example create audio Visualizer for MediaPlayer, reference Android demo example: ApiDemos > Media > AudioTx. Permission android.permission.RECORD_AUDIO is needed,  to use visualizer.

remark@2016-10-18:
I found that the example code removed from Android Studio examples list, may be it is  NOT work now.



Create custom VisualizerView extends View, VisualizerView.java

package com.example.androidaudiovisualizer;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

public class VisualizerView extends View {

 private byte[] mBytes;
 private float[] mPoints;
 private Rect mRect = new Rect();
 private Paint mForePaint = new Paint();

 public VisualizerView(Context context) {
  super(context);
  init();
 }

 public VisualizerView(Context context, AttributeSet attrs) {
  super(context, attrs);
  init();
 }

 public VisualizerView(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  init();
 }

 private void init() {
  mBytes = null;
  mForePaint.setStrokeWidth(1f);
  mForePaint.setAntiAlias(true);
  mForePaint.setColor(Color.rgb(0, 128, 255));
 }

 public void updateVisualizer(byte[] bytes) {
  mBytes = bytes;
  invalidate();
 }

 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  if (mBytes == null) {
   return;
  }
  if (mPoints == null || mPoints.length < mBytes.length * 4) {
   mPoints = new float[mBytes.length * 4];
  }
  mRect.set(0, 0, getWidth(), getHeight());
  for (int i = 0; i < mBytes.length - 1; i++) {
   mPoints[i * 4] = mRect.width() * i / (mBytes.length - 1);
   mPoints[i * 4 + 1] = mRect.height() / 2
     + ((byte) (mBytes[i] + 128)) * (mRect.height() / 2) / 128;
   mPoints[i * 4 + 2] = mRect.width() * (i + 1) / (mBytes.length - 1);
   mPoints[i * 4 + 3] = mRect.height() / 2
     + ((byte) (mBytes[i + 1] + 128)) * (mRect.height() / 2)
     / 128;
  }
  canvas.drawLines(mPoints, mForePaint);
 }

}

Add <com.example.androidaudiovisualizer.VisualizerView> to layout file, activity_main.xml.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.androidaudiovisualizer.MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />
    
    <com.example.androidaudiovisualizer.VisualizerView
        android:id="@+id/myvisualizerview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

MainActivity.java

package com.example.androidaudiovisualizer;

import android.support.v7.app.ActionBarActivity;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.audiofx.Visualizer;
import android.os.Bundle;

/*
 * Copy test.mp3 to /res/raw/ folder
 * 
 * needed in AndroidManifest.xml
 * android:minSdkVersion="9"
 * uses-permission of "android.permission.RECORD_AUDIO"
 * 
 * reference: Android demo example -
 * ApiDemos > Media > AudioTx
 */

public class MainActivity extends ActionBarActivity {

 VisualizerView mVisualizerView;

 private MediaPlayer mMediaPlayer;
 private Visualizer mVisualizer;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  mVisualizerView = (VisualizerView) findViewById(R.id.myvisualizerview);

  initAudio();
 }

 @Override
 protected void onPause() {
  super.onPause();
  if (isFinishing() && mMediaPlayer != null) {
   mVisualizer.release();
   mMediaPlayer.release();
   mMediaPlayer = null;
  }
 }

 private void initAudio() {
  setVolumeControlStream(AudioManager.STREAM_MUSIC);
  mMediaPlayer = MediaPlayer.create(this, R.raw.test);

  setupVisualizerFxAndUI();
  // Make sure the visualizer is enabled only when you actually want to
  // receive data, and
  // when it makes sense to receive data.
  mVisualizer.setEnabled(true);
  // When the stream ends, we don't need to collect any more data. We
  // don't do this in
  // setupVisualizerFxAndUI because we likely want to have more,
  // non-Visualizer related code
  // in this callback.
  mMediaPlayer
    .setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
     public void onCompletion(MediaPlayer mediaPlayer) {
      mVisualizer.setEnabled(false);
     }
    });
  mMediaPlayer.start();

 }

 private void setupVisualizerFxAndUI() {

  // Create the Visualizer object and attach it to our media player.
  mVisualizer = new Visualizer(mMediaPlayer.getAudioSessionId());
  mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
  mVisualizer.setDataCaptureListener(
    new Visualizer.OnDataCaptureListener() {
     public void onWaveFormDataCapture(Visualizer visualizer,
       byte[] bytes, int samplingRate) {
      mVisualizerView.updateVisualizer(bytes);
     }

     public void onFftDataCapture(Visualizer visualizer,
       byte[] bytes, int samplingRate) {
     }
    }, Visualizer.getMaxCaptureRate() / 2, true, false);
 }

}

Next example:
- Visible DTMF Piano: Visualizer + ToneGenerator