Implement Android MP3 Player using MediaPlayer

MediaPlayer class can be used to control playback of audio/video files and streams. It is a example to implement MP3 Player using MediaPlayer. Please note that you have to keep follow the State Diagram, otherwise IllegalStateException will be thrown.

Create a new Android Project in Eclipse, using the auto-generated code extend from ActionBarActivity.

The mp3 file is stored in /res/raw/vespers.mp3. Filename match with the following code in initMediaPlayer().

mediaPlayer = MediaPlayer.create(getActivity(), R.raw.vespers);

MainActivity.java

package com.example.androidmp3player;

import android.support.v7.app.ActionBarActivity;
import android.support.v4.app.Fragment;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {

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

  if (savedInstanceState == null) {
   getSupportFragmentManager().beginTransaction()
     .add(R.id.container, new PlaceholderFragment()).commit();
  }
 }

 @Override
 public boolean onCreateOptionsMenu(Menu menu) {

  // Inflate the menu; this adds items to the action bar if it is present.
  getMenuInflater().inflate(R.menu.main, menu);
  return true;
 }

 @Override
 public boolean onOptionsItemSelected(MenuItem item) {
  // Handle action bar item clicks here. The action bar will
  // automatically handle clicks on the Home/Up button, so long
  // as you specify a parent activity in AndroidManifest.xml.
  int id = item.getItemId();
  if (id == R.id.action_settings) {
   return true;
  }
  return super.onOptionsItemSelected(item);
 }

 /**
  * A placeholder fragment containing a simple view.
  */
 public static class PlaceholderFragment extends Fragment {

  Button btnStart, btnPause, btnStop, btnSeek;
  TextView textState, textDuration, textPosition;

  MediaPlayer mediaPlayer;

  private int stateMediaPlayer;
  private final int STATE_Idle = 0;
  private final int STATE_Initialized = 1;
  private final int STATE_Preparing = 2;
  private final int STATE_Prepared = 3;
  private final int STATE_Started = 4;
  private final int STATE_Paused = 5;
  private final int STATE_Stopped = 6;
  private final int STATE_PlaybackCompleted = 7;
  private final int STATE_End = 8;
  private final int STATE_Error = 9;
  
  public PlaceholderFragment() {
  }

  @Override
  public void onCreate(Bundle savedInstanceState) {
   // TODO Auto-generated method stub
   super.onCreate(savedInstanceState);
   initMediaPlayer();
  }

  @Override
  public void onDestroy() {

   Toast.makeText(getActivity(), 
    "release mediaPlayer", 
    Toast.LENGTH_LONG).show();
   mediaPlayer.release();
   mediaPlayer = null;
   setPlayerState(STATE_End);
   
   super.onDestroy();
  }

  @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container,
    Bundle savedInstanceState) {
   View rootView = inflater.inflate(R.layout.fragment_main, container,
     false);
   btnStart = (Button) rootView.findViewById(R.id.start);
   btnPause = (Button) rootView.findViewById(R.id.pause);
   btnStop = (Button) rootView.findViewById(R.id.stop);
   btnSeek = (Button) rootView.findViewById(R.id.seekto);
   
   btnStart.setOnClickListener(new OnClickListener() {
    
    @Override
    public void onClick(View v) {
     
     if(stateMediaPlayer==STATE_Prepared 
      || stateMediaPlayer==STATE_Started
      || stateMediaPlayer==STATE_Paused
      || stateMediaPlayer==STATE_PlaybackCompleted){
      mediaPlayer.start();
      setPlayerState(STATE_Started);
      
      displayDurationPosition();
     }else{
      Toast.makeText(getActivity(), 
       "Play at Invalid state!", 
       Toast.LENGTH_LONG).show();
     }
    }
   });
   
   btnPause.setOnClickListener(new OnClickListener() {
    
    @Override
    public void onClick(View v) {
     
     if(stateMediaPlayer==STATE_Started
      || stateMediaPlayer==STATE_Paused
      || stateMediaPlayer==STATE_PlaybackCompleted){
      mediaPlayer.pause();
      setPlayerState(STATE_Paused);
      
      displayDurationPosition();
     }else{
      Toast.makeText(getActivity(), 
       "Pause at Invalid state!", 
       Toast.LENGTH_LONG).show();
     }
    }
   });
   
   btnStop.setOnClickListener(new OnClickListener() {
    
    @Override
    public void onClick(View v) {
     
     if(stateMediaPlayer==STATE_Prepared
      || stateMediaPlayer==STATE_Started
      || stateMediaPlayer==STATE_Stopped
      || stateMediaPlayer==STATE_Paused
      || stateMediaPlayer==STATE_PlaybackCompleted){
      
      //Stop
      mediaPlayer.stop();
      setPlayerState(STATE_Stopped);
      
      //then parepare in background thread
      mediaPlayer.prepareAsync();
      setPlayerState(STATE_Preparing);
      
      displayDurationPosition();
     }else{
      Toast.makeText(getActivity(), 
       "Stop at Invalid state!", 
       Toast.LENGTH_LONG).show();
     }
     
    }
   });
   
   btnSeek.setOnClickListener(new OnClickListener(){

    @Override
    public void onClick(View v) {
     if(stateMediaPlayer==STATE_Prepared
      || stateMediaPlayer==STATE_Started
      || stateMediaPlayer==STATE_Paused
      || stateMediaPlayer==STATE_PlaybackCompleted){
      mediaPlayer.seekTo(0);
      
      displayDurationPosition();
     }else{
      Toast.makeText(getActivity(), 
       "SeekTo at Invalid state!", 
       Toast.LENGTH_LONG).show();
     }
    }});
   
   mediaPlayer.setOnPreparedListener(new OnPreparedListener(){

    @Override
    public void onPrepared(MediaPlayer mp) {
     setPlayerState(STATE_Prepared);
     displayDurationPosition();
    }});
   
   mediaPlayer.setOnCompletionListener(new OnCompletionListener(){

    @Override
    public void onCompletion(MediaPlayer mp) {
     setPlayerState(STATE_PlaybackCompleted);
     displayDurationPosition();
    }});

   textState = (TextView) rootView.findViewById(R.id.state);
   textState.setText(getPlayerState());
   
   textDuration = (TextView) rootView.findViewById(R.id.duration);
   textPosition = (TextView) rootView.findViewById(R.id.position);
   displayDurationPosition();
   
   textDuration.setOnClickListener(new OnClickListener(){

    @Override
    public void onClick(View v) {
     displayDurationPosition();
    }});
   
   textPosition.setOnClickListener(new OnClickListener(){

    @Override
    public void onClick(View v) {
     displayDurationPosition();
    }});
   
   return rootView;
  }
  
  private void displayDurationPosition(){
   textDuration.setText(
     "Duration: " + mediaPlayer.getDuration() + " ms");
   textPosition.setText(
     "Current Position: " + mediaPlayer.getCurrentPosition() + " ms");
  }

  private void initMediaPlayer() {
   Toast.makeText(getActivity(), 
     "initMediaPlayer()", 
     Toast.LENGTH_LONG).show();
   mediaPlayer = MediaPlayer.create(getActivity(), R.raw.vespers);
   setPlayerState(STATE_Prepared);
  }
  
  private void setPlayerState(int st){
   stateMediaPlayer = st;
   
   String stringState = getPlayerState();
   if(textState!=null){
    textState.setText(stringState);
   }else{
    Toast.makeText(getActivity(), 
      stringState, Toast.LENGTH_LONG).show();
   }
   
  }
  
  private String getPlayerState(){
   String strSt;
   switch(stateMediaPlayer){
   case STATE_Idle:
    strSt = "Idle";
    break;
   case STATE_Initialized:
    strSt = "Initialized";
    break;
   case STATE_Preparing:
    strSt = "Preparing";
    break;
   case STATE_Prepared:
    strSt = "Prepared";
    break;
   case STATE_Started:
    strSt = "Started";
    break;
   case STATE_Paused:
    strSt = "Paused";
    break;
   case STATE_Stopped:
    strSt = "Stopped";
    break;
   case STATE_PlaybackCompleted:
    strSt = "PlaybackCompleted";
    break;
   case STATE_End:
    strSt = "End";
    break;
   case STATE_Error:
    strSt = "Error";
    break;
   default:
    strSt = "unknown...";
   }
   return strSt;
  }
 }

}

fragment_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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context="com.example.androidmp3player.MainActivity$PlaceholderFragment" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://arteluzevida.blogspot.com/"
        android:textStyle="bold" />
    
    <Button
        android:id="@+id/start"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Start" />
    <Button
        android:id="@+id/pause"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Pause" />
    <Button
        android:id="@+id/stop"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Stop" />
    <Button
        android:id="@+id/seekto"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Seek To Beginning" />
    <TextView
        android:id="@+id/state"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/duration"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/position"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

Auto generated activity_main.xml.

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.androidmp3player.MainActivity"
    tools:ignore="MergeRootFrame" />

Download the files (not include the mp3 file).

Next:
- Implement OnErrorListener.
- Re-set On..Listener after mediaPlayer.release and re-create MediaPlayer
- Implement time bar for MediaPlayer, also introduce bug of MediaPlayer.seekTo()

Runnable in background thread

This exercise show how to run a Runnable in background.

Runnable in background thread

In this exercise, we need to check if the current thread is the main thread, or called UI thread. Using the code:

Looper.getMainLooper().getThread()==Thread.currentThread()

If it's true, means it's in main thread, otherwise it's in background thread.

The example show how to implement a Thread with Runnable object. And call its start() method to starts the new Thread of execution. Also notice that if you call its run() method, it will calls the run() method of the Runnable object directly, in current thread.

package com.example.androidthread;

import android.os.Bundle;
import android.os.Looper;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.app.Activity;

public class MainActivity extends Activity {
 
 Button buttonStart, buttonRun;
 TextView textInfo;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  buttonStart = (Button)findViewById(R.id.buttonstart);
  buttonRun = (Button)findViewById(R.id.buttonrun);
  textInfo = (TextView)findViewById(R.id.info);
  
  buttonStart.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View arg0) {
    Thread thread = new Thread(new MyRunnable());
    thread.start(); //in background thread
   }});
  
  buttonRun.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View arg0) {
    Thread thread = new Thread(new MyRunnable());
    thread.run(); //in current thread
   }});
 }

 private class MyRunnable implements Runnable {

  @Override
  public void run() {
   // check if it's run in main thread, or background thread
   if(Looper.getMainLooper().getThread()==Thread.currentThread()){
    //in main thread
    textInfo.setText("in main thread");
   }else{
    //in background thread

    runOnUiThread(new Runnable(){

     @Override
     public void run() {
      textInfo.setText("in background thread");
     }
     
    });
   }
  }
  
 }

}

<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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context=".MainActivity" >
    
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://arteluzevida.blogspot.com/"
        android:textStyle="bold" />
    <Button
        android:id="@+id/buttonstart"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="start()" />
    <Button
        android:id="@+id/buttonrun"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="run()" />
    <TextView
        android:id="@+id/info"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

More example about Thread:
- Set name of Thread
- Share object between threads with synchronized methods
- Share object between threads with synchronized Statements
- Synchronized Statements with separate lock object, I
- Synchronized Statements with separate lock object, II
- Example of using Lock/ReentrantLock
- Solve Producer–consumer problem with wait() and notifyAll()

Android USB Host Mode, step-by-step

When your Android-powered device is in USB host mode, it acts as the USB host, powers the bus, and enumerates connected USB devices. USB host mode is supported in Android 3.1 and higher.

To use Android devices as Host, a USB OTG (On-The-Go) cable is needed, to be connected to Android side.

I'm do some exercise on Android USB Host Mode, here is the list of the related posts.

• List attached USB devices in USB Host mode
• List UsbDevice, UsbInterface and UsbEndpoint in USB Host mode
• Read iManufacturer and iProduct of USB Device from raw Device Descriptors
• Search USB device for specified Vendor ID and Product ID
• Use intent filter to detect a specified USB device and auto start application
• cat /system/etc/permissions/handheld_core_hardware.xml on your Android device
• Get type and direction of UsbEndpoint
• Search UsbInterface and UsbEndpoint, of USB_ENDPOINT_XFER_BULK type, with both USB_DIR_OUT and USB_DIR_IN
• Send Hello to Arduino from Android in USB Host Mode
• Android send command to Arduino in USB Host mode

ActionBarCompat

Back to when Android 4.3 and Nexus 7 announced, Google released a new backward-compatible Action Bar implementation called ActionBarCompat that's part of the Support Library r18. The ActionBarCompat APIs let you build the essential Action Bar design pattern into your app, with broad compatibility back to Android 2.1.

The post in Android Developers Blog helps you get started with ActionBarCompat, from setting up the Support Library to adding an Action Bar to your UI.


An introduction to this new support library, which allows you to add a compatible Action Bar to your application, targeting Android v2.1 or newer. This DevByte covers integrating the library, from adding it as a dependency to modifying your resources and code.

For more information you can visit -
http://developer.android.com/guide/topics/ui/actionbar.html

---

ActionBarCompat Step-by-step:

• Create library project with the appcompat v7 support library
• Example of using ActionBarCompat with android-support-v7-appcompat
• Add MenuItem to ActionBarCompat using Java
• Handle onOptionsItemSelected() for ActionBarCompat
• ActionBarCompat with Share ShareActionProvider
• ActionBarCompat with ShareActionProvider to update dynamic content

Example of ViewAnimator

android.widget.ViewAnimator is a subclass of FrameLayout container that will perform animations when switching between its views.

<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=".MainActivity" >

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

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <Button
            android:id="@+id/prev"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="previous" />

        <Button
            android:id="@+id/next"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="next" />
    </LinearLayout>

    <ViewAnimator
        android:id="@+id/viewanimator"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/ic_launcher" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="TextView 1" />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Button 2" />

        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Button 3" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:gravity="center" >

            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="- Button 4 -" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="LinearLayout 4" />
        </LinearLayout>
    </ViewAnimator>

</LinearLayout>

package com.example.androidviewanimator;

import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.ViewAnimator;

public class MainActivity extends Activity {
 
 Button buttonPrev, buttonNext;
 ViewAnimator viewAnimator;
 
 Animation slide_in_left, slide_out_right;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  
  buttonPrev = (Button)findViewById(R.id.prev);
  buttonNext = (Button)findViewById(R.id.next);
  viewAnimator = (ViewAnimator)findViewById(R.id.viewanimator);
  
  slide_in_left = AnimationUtils.loadAnimation(this, android.R.anim.slide_in_left);
  slide_out_right = AnimationUtils.loadAnimation(this, android.R.anim.slide_out_right);
  
  viewAnimator.setInAnimation(slide_in_left);
  viewAnimator.setOutAnimation(slide_out_right);
  
  buttonPrev.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View arg0) {
    viewAnimator.showPrevious();
   }});
  
  buttonNext.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View arg0) {
    viewAnimator.showNext();
   }});
 }

}

---

more related example:

• ViewSwitcher
• ImageSwitcher
• TextSwitcher
• ViewFlipper
• Bi-direction sliding
• Using GestureDetector to detect user swipe, onFling()
• Detect Gesture by implementing GestureDetector.SimpleOnGestureListener

Something about processing images in Android

I will do some trial experience about image in Android programming. The list here will be updated once posted.

• Combine bitmap side-by-side
• Merge two image, overlap with Alpha
• Example to draw Bitmap with ShadowLayer
• Draw text on bitmap using Canvas.drawText()
• Merge images with PorterDuffXfermode
• Create frame on Bitmap image
• Create shadow frame for image
• Share bitmap between Activities
• Handle error of 'OutOfMemoryError' and 'Bitmap too large to be uploaded into a texture' for images/bitmaps
• Load scaled bitmap
• Fine tune scaled down bitmap to exact size
• Detect touch event and position on ImageView
• Get bitmap color on touched position in ImageView
• Detect touch and free draw on Bitmap
• Detect touch and draw rect on bitmap
• Create mirror bitmap with matrix
• Create upside down bitmap with matrix
• Convert Bitmap to Drawable with BitmapDrawable
• Combine bitmap, half/half
• Adjust HSV(Hue, Saturation and Value) of bitmap
• Scale bitmap with inDither and inPreferQualityOverSpeed
• Adjust saturation of Bitmap with ColorMatrix
• Set the rotation on a color axis of Bitmap with ColorMatrix
• Scale color and alpha of colormatrix with setScale()
• ColorMatrix.setConcat() to combine ColorMatrixs
• Convert Bitmap to gray-scale with ColorMatrix
• Learn how to use the Android NDK, by creating an image processing application
• Example to apply BlurMaskFilter on Bitmap
• Blur bitmap
• Blur bitmap using Convolution
• Sharpen bitmap using Convolution
• Good official lessons teach Caching Bitmaps and Managing Bitmap Memory

Related demo video:

The exercises have not take care the bitmap size, and any resizing. So don't test with big picture, otherwise OutOfMemoryError or "Bitmap too large to be uploaded into a texture" will happen.

YouTube Android Player API step-by-step

The YouTube Android Player API enables you to incorporate video playback functionality into your Android applications. The API defines methods for loading and playing YouTube videos (and playlists) and for customizing and controlling the video playback experience.

Using the API, you can load or cue videos into a player view embedded in your application's UI. You can then control playback programmatically. For example, you can play, pause, or seek to a specific point in the currently loaded video.

You can also register event listeners to get callbacks for certain events, such as the player loading a video or the player state changing. Finally, the API has helper functionality to support orientation changes as well as transitions to fullscreen playback.

---

Develop Android App with YouTube Android Player API step-by-step:

• Download and import YouTube Android Player API
• Register your app using YouTube Android Player API and obtain API Key
• Simple example using YouTube Android Player API
• YouTubeThumbnailView example
• Handle initialization error YouTube API Service
• Handle player state changes and playback events, by implementing PlayerStateChangeListener and PlaybackEventListener
• Force YouTube Android Player to run in full screen mode
• Example to use YouTubePlayerFragment of YouTube Android Player API
• Load specified YouTube playlist

Related:

• YouTube API Video Tutorials, YouTube for Developers