Android开发---MediaPlayer简单音乐播放器

实践是知识的母亲,知识是生活的明灯。这篇文章主要讲述Android开发---MediaPlayer简单音乐播放器相关的知识,希望能为你提供帮助。
android开发—MediaPlayer简单音乐播放器 功能介绍

  • 实现一个简单的播放器, 类似网易云音乐形式, 功能包括:
    1. 播放、暂停, 停止, 退出功能;
    2. 后台播放功能;
    3. 进度条显示播放进度、拖动进度条改变进度功能;
    4. 播放时图片旋转, 显示当前播放时间功能;
  • 界面样式
    Android开发---MediaPlayer简单音乐播放器

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功能实现 1. MediaPlayer的实现
  • MediaPlayer常用方法介绍
  • Android开发---MediaPlayer简单音乐播放器

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    MediaPlayer的实现包括初始化MediaPlayer, MediaPlayer的功能实现, 包括播放、暂停、停止、离开等, 具体细节如下:
    MediaPlayer的初始化包括读取一个MP3格式的音乐文件并设置其为循环播放:
public void initMediaPlayer() { try { //String file_path = " /storage/0123-4567/K.Will-Melt.mp3" ; String file_path = Environment.getExternalStorageDirectory().getAbsolutePath()+ " /K.Will-Melt.mp3" ; //String file_path = " /data/K.Will-Melt.mp3" ; mediaPlayer.setDataSource(file_path); mediaPlayer.prepare(); mediaPlayer.setLooping(true); // 设置循环播放 } catch (Exception e) { e.printStackTrace(); } }

播放/暂停功能的实现放在Play/Pause按钮中, 所以需要二选一判断MediaPlayer的状态来设置音乐的播放与暂停:
public void playOrPause() { flag+ + ; if (flag > = 1000) flag = 2; which = " pause" ; if(mediaPlayer.isPlaying()){ mediaPlayer.pause(); animator.pause(); } else { mediaPlayer.start();

类似的, 停止功能的实现放在Stop按钮中, 用于停止音乐并将其置于初始态即“00:00”:
public void stop() { which = " stop" ; animator.pause(); if(mediaPlayer != null) { mediaPlayer.pause(); mediaPlayer.stop(); try { mediaPlayer.prepare(); mediaPlayer.seekTo(0); } catch (Exception e) { e.printStackTrace(); } } }

说明: 由于调用stop()后, 有时音乐并没有马上停止, 所以我额外加了一个pause()来确保音乐停止播放。
同样, 离开功能实现放在了Quit按钮中, 主要实现整个应用的退出, 具体应包括解绑Service, 结束Activity等等:
private void quit() { musicService.animator.end(); handler.removeCallbacks(runnable); unbindService(sc); try { finish(); System.exit(0); } catch (Exception e) { e.printStackTrace(); } }

2. Service的应用
  • Service即“服务” , 它与Activity属于同一等级的应用程序组件, 都代表可执行的程序。不同的是Activity拥有前台运行的用户界面, 而Service不能自己运行, 需要通过某个Activity或者其他Context对象来调用。Service在后台运行, 它不能与用户直接进行交互。在默认情况下, Service运行在应用程序进程的主线程之中。可以通过Context.startService()和Context.bindService()两种方式来启动Service。
  • 通过Service可以使程序在退出之后仍然能够对事件或用户操作做出反应, 或者在后台继续运行某些程序功能。
  • Android赋予Services比处于不活动( inactivity) 的Activities更高的优先级, 所以它们的进程不会轻易被系统杀掉。
  • Activity与Service的交互示意图为:
    Android开发---MediaPlayer简单音乐播放器

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    有了以上知识的积累, 基本可以实现Service的必要部分,如下:
    1.新建一个继承于Service的MusicService类
public class MusicService extends Service { public final IBinder binder = new MyBinder(); public class MyBinder extends Binder { MusicService getService() { return MusicService.this; } }

/** * onBind 是 Service 的虚方法, 因此我们不得不实现它。 * 返回 null, 表示客服端不能建立到此服务的连接。 */ @ Override public IBinder onBind(Intent intent) { return binder; }

2.并在Activity中绑定MusicService:
@ Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); getOverflowMenu(); setContentView(R.layout.activity_main); bindServiceConnection(); musicService = new MusicService();

private ServiceConnection sc = new ServiceConnection() { @ Override public void onServiceConnected(ComponentName componentName, IBinder iBinder) { musicService = ((MusicService.MyBinder) iBinder).getService(); }@ Override public void onServiceDisconnected(ComponentName componentName) { musicService = null; } }; private void bindServiceConnection() { Intent intent = new Intent(this, MusicService.class); startService(intent); bindService(intent, sc, this.BIND_AUTO_CREATE); }

3. Handler更新UI界面
通过Handler来管理UI, 最要需要用到post和postDelayed两个函数:
1. post(Runnable r)
将r加入到消息队列中( 其实就是利用UI主线程执行一段代码, 这样可以随时在其他线程中调整控件)
2. postDelayed(Runnabled r,long delayMillis)
将r加入到消息队列中, 并在指定时间之后触发( 单位为毫秒)
所以, 为了实现音乐的播放显示等功能, 需要重写Runnable的run函数, 具体实现如下:
public Handler handler = new Handler(); public Runnable runnable = new Runnable() { @ Override public void run() {isPlay.setOnClickListener(new myOnClickListener()); stop.setOnClickListener(new myOnClickListener()); quit.setOnClickListener(new myOnClickListener()); if(musicService.mediaPlayer.isPlaying()) { stateText.setText(" Playing" ); } else { if (musicService.which.equals(" stop" )){ stateText.setText(" Stop" ); } else if (musicService.which.equals(" pause" )){ stateText.setText(" Pause" ); } } playingTime.setText(time.format(musicService.mediaPlayer.getCurrentPosition())); totalTime.setText(time.format(musicService.mediaPlayer.getDuration())); seekBar.setProgress(musicService.mediaPlayer.getCurrentPosition()); seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() { @ Override public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { if (fromUser) { musicService.mediaPlayer.seekTo(seekBar.getProgress()); } }@ Override public void onStartTrackingTouch(SeekBar seekBar) {}@ Override public void onStopTrackingTouch(SeekBar seekBar) {} }); handler.postDelayed(runnable, 100); } };

4. 实现图片的旋转
图片的动画效果实现需要用到ObjectAnimator类, ObjectAnimator类可用于图片的平移、旋转、缩放等动画, 此处我们只需要用到其旋转功能, 具体实现如下:
publicvoid AnimatorAction() { if (mediaPlayer.isPlaying()) { animator.setDuration(5000); animator.setInterpolator(new LinearInterpolator()); // 均速旋转 animator.setRepeatCount(ValueAnimator.INFINITE); // 无限循环 animator.setRepeatMode(ValueAnimator.INFINITE); animator.start(); } }

说明: animator是ObjectAnimator的一个实例对象, setDuration为5000表示旋转一周需要的时间为5000, 所以可用来设置旋转的速度; 同时设置为无线循环模式, 并且添加一个插值器达到匀速旋转的目的, 最后调用pause()等函数动态控制动画状态, 如下:
Android开发---MediaPlayer简单音乐播放器

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5. 进度条SeekBar功能实现
SeekBar的功能包括显示歌曲播放进度以及拖动SeekBar至任意位置来改变播放进度, 由于android已经封装好了这些函数, 所以直接调用就好了, 也比较好理解, 具体实现如下:
seekBar = (SeekBar) findViewById(R.id.seekBar); seekBar.setProgress(musicService.mediaPlayer.getCurrentPosition()); seekBar.setMax(musicService.mediaPlayer.getDuration());

seekBar.setProgress(musicService.mediaPlayer.getCurrentPosition()); seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() { @ Override public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { if (fromUser) { musicService.mediaPlayer.seekTo(seekBar.getProgress()); } }@ Override public void onStartTrackingTouch(SeekBar seekBar) {}@ Override public void onStopTrackingTouch(SeekBar seekBar) {} });

6. 动态权限申请
参见Android动态权限申请
7. 判断程序是否处于后台
由于音乐需要支持后台播放, 再次由后台进入前台会对前台的事件功能等产生影响, 所以可以添加一个后台判断函数, 并添加一个标志来记录应用是否进入后台。
private boolean isApplicationBroughtToBackground() { ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE); List< ActivityManager.RunningTaskInfo> tasks = am.getRunningTasks(1); if (!tasks.isEmpty()) { ComponentName topActivity = tasks.get(0).topActivity; if (!topActivity.getPackageName().equals(getPackageName())) { return true; } } return false; }

附上MainActivity和Service部分的完整代码
  • MainActivity.java
package com.example.kx.temp; import android.Manifest; import android.animation.ObjectAnimator; import android.animation.ValueAnimator; import android.app.Activity; import android.app.ActivityManager; import android.content.ComponentName; import android.content.Context; import android.content.Intent; import android.content.ServiceConnection; import android.content.pm.PackageManager; import android.media.MediaPlayer; import android.net.Uri; import android.os.Environment; import android.os.Handler; import android.os.IBinder; import android.support.v4.app.ActivityCompat; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.util.Log; import android.view.Menu; import android.view.View; import android.view.ViewConfiguration; import android.view.animation.LinearInterpolator; import android.widget.Button; import android.widget.ImageView; import android.widget.SeekBar; import android.widget.TextView; import com.google.android.gms.appindexing.Action; import com.google.android.gms.appindexing.AppIndex; import com.google.android.gms.common.api.GoogleApiClient; import java.lang.reflect.Field; import java.text.SimpleDateFormat; import java.util.List; public class MainActivity extends AppCompatActivity {private Button isPlay; private Button stop; private Button quit; private ImageView coverImage; // private ObjectAnimator animator; private int flag = 0; private TextView totalTime; private TextView playingTime; private TextView stateText; private SeekBar seekBar; private TextView pathText; @ Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); getOverflowMenu(); setContentView(R.layout.activity_main); bindServiceConnection(); musicService = new MusicService(); coverImage = (ImageView) findViewById(R.id.coverImage); musicService.animator = ObjectAnimator.ofFloat(coverImage, " rotation" , 0, 359); isPlay = (Button) findViewById(R.id.isPlayButton); isPlay.setOnClickListener(new myOnClickListener()); stop = (Button) findViewById(R.id.stopButton); stop.setOnClickListener(new myOnClickListener()); quit = (Button) findViewById(R.id.quitButton); quit.setOnClickListener(new myOnClickListener()); seekBar = (SeekBar) findViewById(R.id.seekBar); seekBar.setProgress(musicService.mediaPlayer.getCurrentPosition()); seekBar.setMax(musicService.mediaPlayer.getDuration()); totalTime = (TextView) findViewById(R.id.totalTime); playingTime = (TextView) findViewById(R.id.playingTime); stateText = (TextView) findViewById(R.id.stateText); pathText = (TextView) findViewById(R.id.pathText); String sdcard = " 音乐文件的路径为: " + Environment.getExternalStorageDirectory().getAbsolutePath().toString()+ " /K.Will-Melt.mp3" ; pathText.setText(sdcard); }private MusicService musicService; private SimpleDateFormat time = new SimpleDateFormat(" mm:ss" ); private ServiceConnection sc = new ServiceConnection() { @ Override public void onServiceConnected(ComponentName componentName, IBinder iBinder) { musicService = ((MusicService.MyBinder) iBinder).getService(); }@ Override public void onServiceDisconnected(ComponentName componentName) { musicService = null; } }; private void bindServiceConnection() { Intent intent = new Intent(this, MusicService.class); startService(intent); bindService(intent, sc, this.BIND_AUTO_CREATE); }public Handler handler = new Handler(); public Runnable runnable = new Runnable() { @ Override public void run() {isPlay.setOnClickListener(new myOnClickListener()); stop.setOnClickListener(new myOnClickListener()); quit.setOnClickListener(new myOnClickListener()); if(musicService.mediaPlayer.isPlaying()) { stateText.setText(" Playing" ); } else { if (musicService.which.equals(" stop" )){ stateText.setText(" Stop" ); } else if (musicService.which.equals(" pause" )){ stateText.setText(" Pause" ); } } playingTime.setText(time.format(musicService.mediaPlayer.getCurrentPosition())); totalTime.setText(time.format(musicService.mediaPlayer.getDuration())); seekBar.setProgress(musicService.mediaPlayer.getCurrentPosition()); seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() { @ Override public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { if (fromUser) { musicService.mediaPlayer.seekTo(seekBar.getProgress()); } }@ Override public void onStartTrackingTouch(SeekBar seekBar) {}@ Override public void onStopTrackingTouch(SeekBar seekBar) {} }); handler.postDelayed(runnable, 100); } }; @ Override public void onPause(){ super.onPause(); if(isApplicationBroughtToBackground()) { musicService.isReturnTo = 1; Log.e(" b" ," 后台中" ); } }@ Override public void onRestart() { super.onRestart(); musicService.isReturnTo = 1; }@ Override protected void onResume() {musicService.AnimatorAction(); verifyStoragePermissions(this); if(musicService.mediaPlayer.isPlaying()) { stateText.setText(" Playing" ); } else { if (musicService.which.equals(" stop" )){ stateText.setText(" Stop" ); } else if (musicService.which.equals(" pause" )){ stateText.setText(" Pause" ); } } seekBar.setProgress(musicService.mediaPlayer.getCurrentPosition()); seekBar.setMax(musicService.mediaPlayer.getDuration()); handler.post(runnable); super.onResume(); Log.d(" hint" , " handler post runnable" ); }private class myOnClickListener implements View.OnClickListener { @ Override public void onClick(View view) { switch (view.getId()) { case R.id.isPlayButton: changePlay(); musicService.playOrPause(); break; case R.id.stopButton: musicService.stop(); changeStop(); break; case R.id.quitButton: quit(); break; default: break; } } }private void changePlay() {if(musicService.mediaPlayer.isPlaying()){ stateText.setText(" Pause" ); isPlay.setText(" PLAY" ); //animator.pause(); } else { stateText.setText(" Playing" ); isPlay.setText(" PAUSE" ); } }private void changeStop() { stateText.setText(" Stop" ); seekBar.setProgress(0); //animator.pause(); }private void quit() { musicService.animator.end(); handler.removeCallbacks(runnable); unbindService(sc); try { finish(); System.exit(0); } catch (Exception e) { e.printStackTrace(); } }@ Override public void onStop() { super.onStop(); } @ Override public void onDestroy() { unbindService(sc); super.onDestroy(); }//这里是在登录界面label上右上角添加三个点, 里面可添加其他功能 @ Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.settings, menu); return true; }private void getOverflowMenu() { try { ViewConfiguration config = ViewConfiguration.get(this); Field menuKeyField = ViewConfiguration.class.getDeclaredField(" sHasPermanentMenuKey" ); if (menuKeyField != null) { menuKeyField.setAccessible(true); menuKeyField.setBoolean(config, false); } } catch (Exception e) { e.printStackTrace(); } }private boolean isApplicationBroughtToBackground() { ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE); List< ActivityManager.RunningTaskInfo> tasks = am.getRunningTasks(1); if (!tasks.isEmpty()) { ComponentName topActivity = tasks.get(0).topActivity; if (!topActivity.getPackageName().equals(getPackageName())) { return true; } } return false; }// Storage Permissions private static final int REQUEST_EXTERNAL_STORAGE = 1; private static String[] PERMISSIONS_STORAGE = { Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE }; /** * Checks if the app has permission to write to device storage * * If the app does not has permission then the user will be prompted to grant permissions * * @ param activity */ public static void verifyStoragePermissions(Activity activity) { // Check if we have write permission int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE); if (permission != PackageManager.PERMISSION_GRANTED) { // We don' t have permission so prompt the user ActivityCompat.requestPermissions( activity, PERMISSIONS_STORAGE, REQUEST_EXTERNAL_STORAGE ); } } }

  • Service
package com.example.kx.temp; import android.Manifest; import android.animation.ObjectAnimator; import android.animation.ValueAnimator; import android.app.Activity; import android.app.ActivityManager; import android.app.Service; import android.content.ComponentName; import android.content.Context; import android.content.Intent; import android.content.pm.PackageManager; import android.media.MediaPlayer; import android.os.Binder; import android.os.Environment; import android.os.IBinder; import android.support.v4.app.ActivityCompat; import android.util.Log; import android.view.animation.LinearInterpolator; import java.io.File; import java.util.List; /** * Created by kx on 2016/11/3. */ public class MusicService extends Service { public final IBinder binder = new MyBinder(); public class MyBinder extends Binder { MusicService getService() { return MusicService.this; } }public static int isReturnTo = 0; public static MediaPlayer mediaPlayer = new MediaPlayer(); public static ObjectAnimator animator; public MusicService() { initMediaPlayer(); }public void initMediaPlayer() { try { //String file_path = " /storage/0123-4567/K.Will-Melt.mp3" ; String file_path = Environment.getExternalStorageDirectory().getAbsolutePath()+ " /K.Will-Melt.mp3" ; //String file_path = " /data/K.Will-Melt.mp3" ; mediaPlayer.setDataSource(file_path); mediaPlayer.prepare(); mediaPlayer.setLooping(true); // 设置循环播放 } catch (Exception e) { e.printStackTrace(); } }publicvoid AnimatorAction() { if (mediaPlayer.isPlaying()) { animator.setDuration(5000); animator.setInterpolator(new LinearInterpolator()); // 均速旋转 animator.setRepeatCount(ValueAnimator.INFINITE); // 无限循环 animator.setRepeatMode(ValueAnimator.INFINITE); animator.start(); } } private int flag = 0; public static String which = " " ; public void playOrPause() { flag+ + ; if (flag > = 1000) flag = 2; which = " pause" ; if(mediaPlayer.isPlaying()){ mediaPlayer.pause(); animator.pause(); } else { mediaPlayer.start(); if ((flag = = 1) || (isReturnTo = = 1)) { animator.setDuration(5000); animator.setInterpolator(new LinearInterpolator()); // 均速旋转 animator.setRepeatCount(ValueAnimator.INFINITE); // 无限循环 animator.setRepeatMode(ValueAnimator.INFINITE); animator.start(); } else { animator.resume(); } } } public void stop() { which = " stop" ; animator.pause(); if(mediaPlayer != null) { mediaPlayer.pause(); mediaPlayer.stop(); try { mediaPlayer.prepare(); mediaPlayer.seekTo(0); } catch (Exception e) { e.printStackTrace(); } } }@ Override public void onDestroy() { mediaPlayer.stop(); mediaPlayer.release(); super.onDestroy(); } /** * onBind 是 Service 的虚方法, 因此我们不得不实现它。 * 返回 null, 表示客服端不能建立到此服务的连接。 */ @ Override public IBinder onBind(Intent intent) { return binder; }}

至此, 基于MediaPlayer的简单音乐播放器基本可以实现, 如有错误或疑问, 烦请指出。 【Android开发---MediaPlayer简单音乐播放器】完整项目参见github, 如君心情好, 别忘了加心哦。。。
祝君好心情~

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