最近在做項目的時候遇到一個小問題,就是需要自己寫一個View來控制系統音樂播放器的播允許存取為,並且要能得到現正播放的音樂的資訊,可能剛開始是想省點時間,所以就沒有直接去看源碼,而是上網搜尋了一下,但令我十分驚訝的是網上竟然沒有這個,難道說沒有童鞋做過這個?嘿嘿,啥都不說了,開始:
獲得系統現正播放的音樂的資訊,查看源碼可以知道,在Music應用中有一個MediaPlaybackService.java檔案,內部的代碼我就不寫了,總之就是在播放音樂的時候會在四種情況下發送廣播,這些廣播裡麵包含了現正播放的音樂的資訊,所以我們只要寫一個廣播來接受這些資訊就可以了:
MusicBroadcastReceiver mbr = null;//定義
class MusicBroadcastReceiver extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) { artistName = intent.getStringExtra("artist"); album = intent.getStringExtra("album"); track = intent.getStringExtra("track"); playing = intent.getBooleanExtra("playing",false); duration = intent.getLongExtra("duration",3000); position = intent.getLongExtra("position",1000); Toast.makeText(TestActivity.this, "playing:" + playing, Toast.LENGTH_SHORT).show(); if(playing){ sd.setVisibility(View.VISIBLE); } else{ if((!sd.isOpened())){ sd.setVisibility(View.GONE); } } if(playing){ ((ImageView)findViewById(R.id.play)).setImageResource(R.drawable.music_pause); }else{ ((ImageView)findViewById(R.id.play)).setImageResource(R.drawable.music_play); } ((TextView)findViewById(R.id.musicName)).setText(track ); ((TextView)findViewById(R.id.musicInfo)).setText(artistName + " / " + album);}}
上面寫的是一個廣播界接收者,需要在適當的時機進行註冊,由於MediaPlaybackService發送的是一個粘性廣播,所以我們的這個接收者在應用開啟的時候也可以接收到這個廣播,不需要管上面我的那些個TextView或者是ImageView。
註冊廣播:
@Overrideprotected void onResume() {/** * com.android.music.metachanged * com.android.music.queuechanged", * "com.android.music.playbackcomplete" * "com.android.music.playstatechanged" */mbr = new MusicBroadcastReceiver();IntentFilter intentFilter = new IntentFilter();intentFilter.addAction("com.android.music.metachanged");intentFilter.addAction("com.android.music.queuechanged");intentFilter.addAction("com.android.music.playbackcomplete");intentFilter.addAction("com.android.music.playstatechanged");registerReceiver(mbr, intentFilter);super.onResume();}
登出廣播:
@Overrideprotected void onPause() {if(mbr != null){unregisterReceiver(mbr);}super.onPause();}
控制音樂的播放:
同樣在Music應用中有一個MediaButtonIntentReceiver接受著,當我們我們可以發送特定的廣播來控制音樂的播放,如下:
private static final String SERVICECMD = "com.android.music.musicservicecommand"; private static final String CMDNAME = "command";/* private static final String CMDTOGGLEPAUSE = "togglepause"; private static final String CMDSTOP = "stop";*/ private static final String CMDPAUSE = "pause"; private static final String CMDPLAY = "play"; private static final String CMDPREVIOUS = "previous"; private static final String CMDNEXT = "next";public void click(View v){Intent intent = new Intent(SERVICECMD);switch(v.getId()){case R.id.pre:{intent.putExtra(CMDNAME, CMDPREVIOUS);}break;case R.id.play:{if(playing){intent.putExtra(CMDNAME,CMDPAUSE); ((ImageView)findViewById(R.id.play)).setImageResource(R.drawable.music_play); }else{ intent.putExtra(CMDNAME,CMDPLAY); ((ImageView)findViewById(R.id.play)).setImageResource(R.drawable.music_pause); }}break;case R.id.next:{intent.putExtra(CMDNAME,CMDNEXT);}break;}sendBroadcast(intent);}
放送廣播的時候也可以不給Inent設定Extra,只需要把:
private static final String SERVICECMD = "com.android.music.musicservicecommand"; private static final String CMDNAME = "command";/* private static final String CMDTOGGLEPAUSE = "togglepause"; private static final String CMDSTOP = "stop";*/ private static final String CMDPAUSE = "pause"; private static final String CMDPLAY = "play"; private static final String CMDPREVIOUS = "previous"; private static final String CMDNEXT = "next";替換為private static final String pause = "com.android.music.musicservicecommand.pause";private static final String next = "com.android.music.musicservicecommand.next";private static final String stop = "com.android.music.musicservicecommand.stop";private static final String previous = "com.android.music.musicservicecommand.previous";
然後new Intent(pause/next/stop/previous);等通過sendBroadcast(intent);發送也可以,但是我沒有親自驗證過,大家可以試一下,第一種是驗證過的。
貼出原理圖:下面是我做鎖屏的時候的圖,左邊的部分是鎖屏相關的,不要受它影響。