現在咱們來聊聊android系統中鈴聲的播放,從framework層面說說Ringtone的播放原理,我在android源碼中碰到了播放系統鈴聲中的問題,所以仔細研究了這方面的知識,現在整理一下,給讀者一些幫助,現在我對鈴聲的播放和設置特別親切,不管是短信鈴聲方面的,來電鈴聲,還是日曆鈴聲,email的鈴聲,鬧鐘的鈴聲,都能解決鈴聲方面的bug。前面我說了Notification的播放機制,Android中Notification的framework層講解【安卓源碼解析四】 . 大概給大家說了說,有想了解的可以參考看一看。鈴聲播放的機制都是用MediaPlayer來播放的,通過MediaPlayer來申請AudioManager機制來播放音樂鈴聲的。前面我寫了個調用系統鈴聲和sdcard卡中鈴聲的demo,Android中鈴聲總結【安卓源碼解析一】.這個例子中有一段代碼:通過intent的action來啓動一個選擇系統鈴聲的dialog,這個到底是啓動的哪兒的dialog,今天給大家揭祕一下,希望給大家帶來點幫助:大明原創,轉載請標明出處:http://blog.csdn.net/wdaming1986/article/details/7166134
寫一個intent來啓動播放ringtone的activity:
Intent intent = new Intent(RingtoneManager.ACTION_RINGTONE_PICKER);
// Allow user to pick 'Default'
intent.putExtra(RingtoneManager.EXTRA_RINGTONE_SHOW_DEFAULT, true);
// Show only ringtones
intent.putExtra(RingtoneManager.EXTRA_RINGTONE_TYPE, RingtoneManager.TYPE_NOTIFICATION);
//set the default Notification value
intent.putExtra(RingtoneManager.EXTRA_RINGTONE_DEFAULT_URI, RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION));
// Don't show 'Silent'
intent.putExtra(RingtoneManager.EXTRA_RINGTONE_SHOW_SILENT, true);
startActivityForResult(intent, SMS_RINGTONE_PICKED);
這個activity啓動後就跑到了framework的com.android.internal.app.RingtonePickerActivity裏面去了,在framework部分也可以寫activity類得,這個挺有意思的,哈哈,新發現,有種“山窮水復疑無路,柳暗花明又一村”的感覺!哈哈,這個intent的action發到哪兒去了呢??
在frameworks\base\core\res\AndroidManifest.xml中可以搜到這個action:
<activity android:name="com.android.internal.app.RingtonePickerActivity"
android:theme="@style/Theme.Dialog.Alert"
android:excludeFromRecents="true"
android:multiprocess="true">
<intent-filter>
<action android:name="android.intent.action.RINGTONE_PICKER" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<action android:name="android.intent.action.RINGTONE_PICKER" />這個就是接受這個intent的action動作的對應的activity的類,找這個RingtonePickerActivity.java類,這個類的繼承和實現有點特殊,注意觀察:
public final class RingtonePickerActivity extends AlertActivity implements
AdapterView.OnItemSelectedListener, Runnable, DialogInterface.OnClickListener,
AlertController.AlertParams.OnPrepareListViewListener
這個類繼承AlertActivity並實現了這麼多接口,找到點擊每個選項播放的方法監聽:
private DialogInterface.OnClickListener mRingtoneClickListener =
new DialogInterface.OnClickListener() {
/*
* On item clicked
*/
public void onClick(DialogInterface dialog, int which) {
// Save the position of most recently clicked item
mClickedPos = which;
// Play clip
playRingtone(which, 0);
}
};
然後找到playRingtone(which, 0);這個方法去:
private void playRingtone(int position, int delayMs) {
mHandler.removeCallbacks(this);
mSampleRingtonePos = position;
mHandler.postDelayed(this, delayMs);
}
這個postDelayed(this, delayMs);this代表當前對象,因爲這個類是實現了Runnable接口,所以這時候會走到run方法中去:
public void run() {
if (mSampleRingtonePos == mSilentPos) {
mRingtoneManager.stopPreviousRingtone();
return;
}
/*
* Stop the default ringtone, if it's playing (other ringtones will be
* stopped by the RingtoneManager when we get another Ringtone from it.
* by bw on start
* when it`s not null set the default ringtone is null
* modify by wangxianming in 2011-12-28
*/
if (mDefaultRingtone != null) {
/// if(mDefaultRingtone.isPlaying()){
mDefaultRingtone.stop();
/// }
mDefaultRingtone = null;
}
Ringtone ringtone;
if (mSampleRingtonePos == mDefaultRingtonePos) {
if (mDefaultRingtone == null) {
mDefaultRingtone = RingtoneManager.getRingtone(this, mUriForDefaultItem);
}
ringtone = mDefaultRingtone;
/*
* Normally the non-static RingtoneManager.getRingtone stops the
* previous ringtone, but we're getting the default ringtone outside
* of the RingtoneManager instance, so let's stop the previous
* ringtone manually.
*/
mRingtoneManager.stopPreviousRingtone();
} else {
ringtone = mRingtoneManager.getRingtone(getRingtoneManagerPosition(mSampleRingtonePos));
}
if (ringtone != null) {
ringtone.play();
}
}
這時候找到這裏就基本上找到根源了,ringtone.play();就是播放ringtone音樂的方法;注意:15行,16行,我對源碼進行了修改,這個有點問題,源碼對原生態的音樂格式支持的很好,但是對mid格式的音樂支持的不太好,所以如果播放mid格式的音樂不能用多個mediaplayer來播放,只能用一個來播放,只能hold住一個,不能重複hold這個ringtone,所以把這個mDefaultRingtone = null;每次都置爲空,這樣每次都是一個對象就可以了。這樣播放系統鈴聲就沒有問題了!
再去frameworks\base\media\java\android\media\Ringtone.java這個類去找到play()方法:
public void play() {
if (mAudio == null) {
try {
openMediaPlayer();
} catch (Exception ex) {
Log.e(TAG, "play() caught ", ex);
mAudio = null;
}
}
if (mAudio != null) {
// do not ringtones if stream volume is 0
// (typically because ringer mode is silent).
if (mAudioManager.getStreamVolume(mStreamType) != 0) {
if (mIsLoop){
mAudio.setLooping(true);
}
mAudio.start();
}
}
}
找到openMediaPlayer()方法 :
private void openMediaPlayer() throws IOException {
mAudio = new MediaPlayer();
if (mUri != null) {
mAudio.setDataSource(mContext, mUri);
} else if (mFileDescriptor != null) {
mAudio.setDataSource(mFileDescriptor);
} else if (mAssetFileDescriptor != null) {
// Note: using getDeclaredLength so that our behavior is the same
// as previous versions when the content provider is returning
// a full file.
if (mAssetFileDescriptor.getDeclaredLength() < 0) {
mAudio.setDataSource(mAssetFileDescriptor.getFileDescriptor());
} else {
mAudio.setDataSource(mAssetFileDescriptor.getFileDescriptor(),
mAssetFileDescriptor.getStartOffset(),
mAssetFileDescriptor.getDeclaredLength());
}
} else {
throw new IOException("No data source set.");
}
mAudio.setAudioStreamType(mStreamType);
mAudio.prepare();
}
這樣就把所有的ringtone播放的機制大致能搞清楚了!希望這個流程給大家一些啓發!有問題的可以留言,我看到會給出解釋的,希望高手指點不足之處!大明原創。