Android控制系统音乐

2018-01-05-21-05-58.png

原理：模拟按键来实现
命令：
KeyEvent.KEYCODE_MEDIA_PLAY = 126 打开音乐
KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE = 85 暂停音乐
KeyEvent.KEYCODE_MEDIA_NEXT = 87 下一曲
KeyEvent.KEYCODE_MEDIA_PREVIOUS = 88 上一曲
步骤：

1.Android 4.4 模拟键第1种方法，需要在AndroidManifest中添加权限（重要）

<uses-permission android:name="android.permission.INJECT_EVENTS"
        tools:ignore="ProtectedPermissions" />

2.在代码中实现

Runtime runtime = Runtime.getRuntime();  
try {  
    runtime.exec("input keyevent " + KeyEvent.KEYCODE_MEDIA_PLAY);  
    } catch (IOException e) { // TODO Auto-generated catch block  
    e.printStackTrace();  
} 

3.调节音量

AudioManager mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
//加大音量
mAudioManager.adjustStreamVolume(AudioManager.STREAM_MUSIC,AudioManager.ADJUST_RAISE,
                            AudioManager.FX_FOCUS_NAVIGATION_UP);
//调小音量
mAudioManager.adjustStreamVolume(AudioManager.STREAM_MUSIC,AudioManager.ADJUST_LOWER,
                            AudioManager.FX_FOCUS_NAVIGATION_UP);

以下是整体类代码

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    private AudioManager mAudioManager;

    @BindView(R.id.start)
    Button start;
    @BindView(R.id.pause)
    Button pause;
    @BindView(R.id.next)
    Button next;
    @BindView(R.id.previous)
    Button previous;
    @BindView(R.id.volume_up)
    Button up;
    @BindView(R.id.volume_down)
    Button down;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
        mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
        initView();
    }

    private void initView(){
        start.setOnClickListener(this);
        pause.setOnClickListener(this);
        next.setOnClickListener(this);
        previous.setOnClickListener(this);
        up.setOnClickListener(this);
        down.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        Runtime runtime = Runtime.getRuntime();
        try {
            switch (view.getId()){
                case R.id.start:
                    runtime.exec("input keyevent " + KeyEvent.KEYCODE_MEDIA_PLAY);
                    break;
                case R.id.pause:
                    runtime.exec("input keyevent " + KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE);
                    break;
                case R.id.next:
                    runtime.exec("input keyevent " + KeyEvent.KEYCODE_MEDIA_NEXT);
                    break;
                case R.id.previous:
                    runtime.exec("input keyevent " + KeyEvent.KEYCODE_MEDIA_PREVIOUS);
                    break;
                case R.id.volume_up:
                    mAudioManager.adjustStreamVolume(AudioManager.STREAM_MUSIC,AudioManager.ADJUST_RAISE,
                            AudioManager.FX_FOCUS_NAVIGATION_UP);
                    break;
                case R.id.volume_down:
                    mAudioManager.adjustStreamVolume(AudioManager.STREAM_MUSIC,AudioManager.ADJUST_LOWER,
                            AudioManager.FX_FOCUS_NAVIGATION_UP);
                    break;
                default:
            }
        } catch (IOException e) { // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}