Android Development---MediaPlayer simple music player

Android Development-mediaplayer Simple music player Function Introduction

• Implement a simple player, similar to the NetEase cloud music format, features include:

  1. Play, pause, stop, exit function;
  2. Background playback function;
  3. Progress bar shows playback progress, drag progress bar changes the progress function;
  4. When playing the picture rotation, display the current playing time function;

• Interface style
  

function Implementation 1. Implementation of MediaPlayer

• Introduction to common methods of MediaPlayer
• 
  The implementation of the MediaPlayer includes initialization of the Mediaplayer,mediaplayer function implementation, including playback, pause, stop, leave, etc., the details are as follows:
  MediaPlayer initialization includes reading a music file in a MP3 format and setting it to play in a loop:

publicvoidinitMediaPlayer() {        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();        }    }

The Play/Pause feature is placed in the Play/pause button, so it takes two to select a MediaPlayer state to set the playback and pause of the music:

publicvoidplayOrPause() {        flag++;        if10002;        "pause";        if(mediaPlayer.isPlaying()){            mediaPlayer.pause();            animator.pause();        else {            mediaPlayer.start();

Similarly, the implementation of the STOP function is placed in the Stop button to stop the music and place it in the initial state as "00:00":

publicvoidstop() {        "stop";        animator.pause();        ifnull) {            mediaPlayer.pause();            mediaPlayer.stop();            try {                mediaPlayer.prepare();                mediaPlayer.seekTo(0);            catch (Exception e) {                e.printStackTrace();            }        }    }

Description: Since the call to stop (), sometimes the music does not stop immediately, so I added a pause () to ensure that the music stops playing.

Similarly, leaving the implementation of the function is placed in the Quit button, the main implementation of the entire application exit, specifically including the service, end activity and so on:

privatevoidquit() {        musicService.animator.end();        handler.removeCallbacks(runnable);        unbindService(sc);        try {            finish();            System.exit(0);        catch (Exception e) {            e.printStackTrace();        }    }

2. Application of service

The
• service, which is the application component of the same level as the activity, represents the executable program. The difference is that the activity has a user interface running in the foreground, and the service cannot run itself and needs to be called through an activity or other context object. The service runs in the background, and it cannot interact directly with the user. By default, the service runs in the main thread of the application process. The service can be started in two ways, Context.startservice () and Context.bindservice ().
• enables programs to respond to events or user actions after exiting, or to continue running certain program functions in the background, through service.
• Android gives services a higher priority than inactive (inactivity) activities, so their processes are not easily killed by the system.
• The interaction of the activity with the service is:
  
  with the accumulation of knowledge above, it is essential to implement the necessary parts of the service as follows:
  1. Create a new Musicservice class that inherits from the service

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    publiconBind(Intent intent) {        return binder;    }

2. And bind Musicservice in activity:

@Override    protectedvoidonCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        getOverflowMenu();        setContentView(R.layout.activity_main);        bindServiceConnection();        new MusicService();

PrivateServiceconnection sc =NewServiceconnection () {@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 =NewIntent ( This, Musicservice.class);        StartService (Intent); Bindservice (Intent, SC, This.    Bind_auto_create); }

3. Handler Update UI Interface

Using handler to manage the UI, you need to use both post and postdelayed two functions:
1. Post (Runnable R)
adding r to the message queue (in fact, executing a piece of code with the main thread of the UI so that the control can be adjusted in other threads at any time)
2. postdelayed (runnabled r,long delaymillis)
Adds r to the message queue and fires after a specified time (in milliseconds)
Therefore, in order to achieve the music playback display functions, you need to rewrite the runnable run function, the implementation of the following:

 PublicHandler Handler =NewHandler (); PublicRunnable Runnable =NewRunnable () {@Override         Public void Run() {Isplay.setonclicklistener (NewMyonclicklistener ()); Stop.setonclicklistener (NewMyonclicklistener ()); Quit.setonclicklistener (NewMyonclicklistener ());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 (NewSeekbar.onseekbarchangelistener () {@Override                 Public void onprogresschanged(SeekBar SeekBar,intProgressBooleanFromuser) {if(Fromuser)                    {MusicService.mediaPlayer.seekTo (seekbar.getprogress ()); }                }@Override                 Public void Onstarttrackingtouch(SeekBar SeekBar) {                }@Override                 Public void Onstoptrackingtouch(SeekBar SeekBar)            {                }            }); Handler.postdelayed (runnable, -); }    };

4. Achieve the rotation of the picture

The animation effect of the picture needs to use the Objectanimator class, the Objectanimator class can be used for the image translation, rotation, zooming and other animations, here we only need to use its rotation function, the implementation of the following:

public  voidAnimatorAction() {        if (mediaPlayer.isPlaying()) {            animator.setDuration(5000);            animator.setInterpolator(new// 均速旋转            // 无限循环            animator.setRepeatMode(ValueAnimator.INFINITE);            animator.start();        }    }

Description: Animator is an instance object of Objectanimator, Setduration 5000 means that the time required to rotate a week is 5000, so it can be used to set the speed of rotation, set to the wireless cycle mode, and add a interpolator to achieve a uniform rotation of the purpose , and finally call pause () to dynamically control the animation state as follows:

5. Progress bar Seekbar Function Realization

Seekbar features include displaying the song playback progress and dragging seekbar to any position to change the playback progress, because Android has encapsulated these functions, so the direct call is good, but also better understanding, the implementation of the following:

seekBar = (SeekBar) findViewById(R.id.seekBar);        seekBar.setProgress(musicService.mediaPlayer.getCurrentPosition());        seekBar.setMax(musicService.mediaPlayer.getDuration());

Seekbar.setprogress (MusicService.mediaPlayer.getCurrentPosition ()); Seekbar.setonseekbarchangelistener (NewSeekbar.onseekbarchangelistener () {@Override                 Public void onprogresschanged(SeekBar SeekBar,intProgressBooleanFromuser) {if(Fromuser)                    {MusicService.mediaPlayer.seekTo (seekbar.getprogress ()); }                }@Override                 Public void Onstarttrackingtouch(SeekBar SeekBar) {                }@Override                 Public void Onstoptrackingtouch(SeekBar SeekBar) {                }            });

6. Dynamic Permission Request

See Android Dynamic permission request

7. Determine if the program is in the background

As the music needs to support background play, again from backstage into the foreground will have an impact on the event function of the foreground, so you can add a background judgment function, and add a flag to record whether the application into the background.

privateisApplicationBroughtToBackground() {        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())) {                returntrue;            }        }        returnfalse;    }

At this point, simple music player based on MediaPlayer can be implemented, such as the need for complete project code, can leave the mailbox.

Android Development---MediaPlayer simple music player