1.前言
在10.0的系统定制开发中，在某些按键智能机的功能开发功能中，在某些时候按键音量按得太快的时候，会出现 按键声音响两次的情况，接下来分析下相关功能，然后解决这个问题。
2.按键智能机按键连续响两次的异常处理的核心类
frameworks/base/services/core/java/com/android/server/audio/AudioService.java3.按键智能机按键连续响两次的异常处理的核心功能分析和实现
AudioService是Android系统中提供的一个系统基本的服务，负责管理应用程序和系统的音频资源。它主要负责在操作系统中分配、控制和处理音频资源，以提供高质量、可靠和灵活的音频服务。AudioService还负责管理系统音频路由、音频格式转换、音量控制、音频设备的连接和断开、通知应用程序和服务启动/停止的音频事件等。 Android系统在启动过程中，会加载并初始化各种服务，包括AudioService。
AudioService的初始化通常在SystemServer的启动过程中完成。SystemServer是Android系统启动过程中的核心进程，负责启动和管理系统级别的服务。 AudioService的创建与配置 在SystemServer的启动过程中，会创建AudioService的实例，并进行必要的配置。配置通常包括加载音频相关的配置文件、初始化音频设备、设置音频策略等。 加载音频配置文件 AudioService会加载音频相关的配置文件，如audio_policy.conf等。这些配置文件定义了音频设备的属性、音频路由规则、音频策略等。通过加载这些配置文件，AudioService可以了解系统的音频设备和音频策略。
public AudioService(Context context) {
mContext = context;
mContentResolver = context.getContentResolver();
mAppOps = (AppOpsManager)context.getSystemService(Context.APP_OPS_SERVICE);
mPlatformType = AudioSystem.getPlatformType(context);
mIsSingleVolume = AudioSystem.isSingleVolume(context);
mUserManagerInternal = LocalServices.getService(UserManagerInternal.class);
mActivityManagerInternal = LocalServices.getService(ActivityManagerInternal.class);
PowerManager pm = (PowerManager)context.getSystemService(Context.POWER_SERVICE);
mAudioEventWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "handleAudioEvent");
mVibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
mHasVibrator = mVibrator == null ? false : mVibrator.hasVibrator();
....
int maxCallVolume = SystemProperties.getInt("ro.config.vc_call_vol_steps", -1);
if (maxCallVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] = maxCallVolume;
}
int defaultCallVolume = SystemProperties.getInt("ro.config.vc_call_vol_default", -1);
if (defaultCallVolume != -1 &&
defaultCallVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] &&
defaultCallVolume >= MIN_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] = defaultCallVolume;
} else {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_VOICE_CALL] =
(maxCallVolume * 3) / 4;
}
int maxMusicVolume = SystemProperties.getInt("ro.config.media_vol_steps", -1);
if (maxMusicVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] = maxMusicVolume;
}
int defaultMusicVolume = SystemProperties.getInt("ro.config.media_vol_default", -1);
if (defaultMusicVolume != -1 &&
defaultMusicVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] &&
defaultMusicVolume >= MIN_STREAM_VOLUME[AudioSystem.STREAM_MUSIC]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] = defaultMusicVolume;
} else {
if (isPlatformTelevision()) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] =
MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] / 4;
} else {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] =
MAX_STREAM_VOLUME[AudioSystem.STREAM_MUSIC] / 3;
}
}
int maxAlarmVolume = SystemProperties.getInt("ro.config.alarm_vol_steps", -1);
if (maxAlarmVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_ALARM] = maxAlarmVolume;
}
int defaultAlarmVolume = SystemProperties.getInt("ro.config.alarm_vol_default", -1);
if (defaultAlarmVolume != -1 &&
defaultAlarmVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_ALARM]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_ALARM] = defaultAlarmVolume;
} else {
// Default is 6 out of 7 (default maximum), so scale accordingly.
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_ALARM] =
6 * MAX_STREAM_VOLUME[AudioSystem.STREAM_ALARM] / 7;
}
int maxSystemVolume = SystemProperties.getInt("ro.config.system_vol_steps", -1);
if (maxSystemVolume != -1) {
MAX_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM] = maxSystemVolume;
}
int defaultSystemVolume = SystemProperties.getInt("ro.config.system_vol_default", -1);
if (defaultSystemVolume != -1 &&
defaultSystemVolume <= MAX_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM]) {
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM] = defaultSystemVolume;
} else {
// Default is to use maximum.
AudioSystem.DEFAULT_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM] =
MAX_STREAM_VOLUME[AudioSystem.STREAM_SYSTEM];
}
/** @see AudioManager#playSoundEffect(int) */
public void playSoundEffect(int effectType) {
playSoundEffectVolume(effectType, -1.0f);
}
/** @see AudioManager#playSoundEffect(int, float) */
public void playSoundEffectVolume(int effectType, float volume) {
// do not try to play the sound effect if the system stream is muted
if (isStreamMutedByRingerOrZenMode(STREAM_SYSTEM)) {
return;
}
if (effectType >= AudioManager.NUM_SOUND_EFFECTS || effectType < 0) {
Log.w(TAG, "AudioService effectType value " + effectType + " out of range");
return;
}
sendMsg(mAudioHandler, MSG_PLAY_SOUND_EFFECT, SENDMSG_QUEUE,
effectType, (int) (volume * 1000), null, 0);
}
/**
* Loads samples into the soundpool.
* This method must be called at first when sound effects are enabled
*/
public boolean loadSoundEffects() {
int attempts = 3;
LoadSoundEffectReply reply = new LoadSoundEffectReply();
synchronized (reply) {
sendMsg(mAudioHandler, MSG_LOAD_SOUND_EFFECTS, SENDMSG_QUEUE, 0, 0, reply, 0);
while ((reply.mStatus == 1) && (attempts-- > 0)) {
try {
reply.wait(SOUND_EFFECTS_LOAD_TIMEOUT_MS);
} catch (InterruptedException e) {
Log.w(TAG, "loadSoundEffects Interrupted while waiting sound pool loaded.");
}
}
}
return (reply.mStatus == 0);
}
/**
* Schedule loading samples into the soundpool.
* This method can be overridden to schedule loading at a later time.
*/
protected void scheduleLoadSoundEffects() {
sendMsg(mAudioHandler, MSG_LOAD_SOUND_EFFECTS, SENDMSG_QUEUE, 0, 0, null, 0);
}
/**
* Unloads samples from the sound pool.
* This method can be called to free some memory when
* sound effects are disabled.
*/
public void unloadSoundEffects() {
sendMsg(mAudioHandler, MSG_UNLOAD_SOUND_EFFECTS, SENDMSG_QUEUE, 0, 0, null, 0);
}在上述的AudioService.java中，在AudioManager的playSoundEffect用于播放Beep音效的就是playSoundEffect(@SystemSoundEffect int effectType) 主要就是调用调用playSoundEffectVolume方法，所以就具体判断两次按键音的时间，然后决定是否调用按键音来实现功能
+ long mLastSystemTimer = -1;
//add by lixu for play sound when button click
public void playSoundEffect(int effectType) {
- Log.e(TAG, "lixu AudioService playSoundEffectYrct effectType = " + effectType);
-
+ long currentTimeMillis = java.lang.System.currentTimeMillis();
+ //Log.e(TAG, "lixu AudioService playSoundEffectYrct effectType = " + effectType +"---timer:"+(mLastSystemTimer!=-1?(currentTimeMillis-mLastSystemTimer):-1));
+ if(mLastSystemTimer!=-1&¤tTimeMillis-mLastSystemTimer<=100)return;
playSoundEffectVolume(effectType, -1.0f);
+ mLastSystemTimer = currentTimeMillis;
}