Android 触摸提示音

近期任务，涉及Android触摸提示音。

首先，定位源码目标。很显然的，在原生的设置的声音功能页里面就包含了触摸音的开关。

那么我们找到对应的java代码，SoundSettings.java

package com.android.settings;
import java.util.List;

public class SoundSettings extends SettingsPreferenceFragment implements
Preference.OnPreferenceChangeListener {

可以看到 这是个PreferenceFragment的子类。（这里的SettingsPreferenceFragment是继承PreferenceFragment）。那么找到它对应的xml文件。

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ContentResolver resolver = getContentResolver();
int activePhoneType = TelephonyManager.getDefault().getCurrentPhoneType();

mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);

addPreferencesFromResource(R.xml.sound_settings);

常识性的，它在onCreate里面，找到addPreferencesFromResource,然后查看sound_settings的xml文件。

这里我通过查找中文string资源文件，标示了xml文件的一些item的title。

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
android:title="@string/sound_settings"
android:key="sound_settings"
xmlns:settings="http://schemas.android.com/apk/res/com.android.settings">

<!-- 音量-->
<com.android.settings.RingerVolumePreference
android:key="ring_volume"
android:title="@string/all_volume_title"
android:dialogTitle="@string/all_volume_title"
android:persistent="false"
android:streamType="ring" />
<!-- 音乐效果-->
<Preference
android:key="musicfx"
android:title="@string/musicfx_title">
<intent android:targetPackage="com.android.musicfx"
android:targetClass="com.android.musicfx.ControlPanelPicker" />
</Preference>
<!-- 来电铃声和振动-->
<PreferenceCategory
android:key="category_calls_and_notification"
android:title="@string/sound_category_call_ringtone_vibrate_title"/>

<!-- Do not nest these, or removals in code will break
手机铃声
-->
<com.android.settings.DefaultRingtonePreference
android:key="ringtone"
android:title="@string/ringtone_title"
android:dialogTitle="@string/ringtone_title"
android:persistent="false"
android:ringtoneType="ringtone" />

<!-- 响铃时振动-->
<CheckBoxPreference
android:key="vibrate_when_ringing"
android:title="@string/vibrate_when_ringing_title"
android:persistent="false" />
<!-- 系统-->
<PreferenceCategory
android:title="@string/sound_category_system_title"/>

<!-- Do not nest these, or removals in code will break -->
<!-- 默认通知提示音-->
<com.android.settings.DefaultRingtonePreference
android:key="notification_sound"
android:title="@string/notification_sound_title"
android:dialogTitle="@string/notification_sound_dialog_title"
android:persistent="false"
android:ringtoneType="notification" />

<!-- 拨号键盘触摸音效-->
<CheckBoxPreference
android:key="dtmf_tone"
android:title="@string/dtmf_tone_enable_title"
android:defaultValue="true" />
<!-- 触摸提示音-->
<CheckBoxPreference
android:key="sound_effects"
android:title="@string/sound_effects_enable_title"
android:defaultValue="true" />

<!-- 锁屏提示音-->
<CheckBoxPreference
android:key="lock_sounds"
android:title="@string/lock_sounds_enable_title"
android:defaultValue="true" />
<!-- 触摸时振动-->
<CheckBoxPreference
android:key="haptic_feedback"
android:title="@string/haptic_feedback_enable_title"
android:defaultValue="true" />
<!-- 紧急提示音-->
<ListPreference
android:key="emergency_tone"
android:title="@string/emergency_tone_title"
android:entries="@array/emergency_tone_entries"
android:entryValues="@array/emergency_tone_values" />

OK，接着我们在SoundSettings里面搜索关键字: sound_effects

private static final String KEY_SOUND_EFFECTS = "sound_effects";

接着搜索：KEY_SOUND_EFFECTS

// 触摸提示音相关
mSoundEffects = (CheckBoxPreference) findPreference(KEY_SOUND_EFFECTS);
mSoundEffects.setPersistent(false);
mSoundEffects.setChecked(Settings.System.getInt(resolver,
Settings.System.SOUND_EFFECTS_ENABLED, 1) != 0);

@Override
public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen, Preference preference) {
if (preference == mVibrateWhenRinging) {
Settings.System.putInt(getContentResolver(), Settings.System.VIBRATE_WHEN_RINGING,
mVibrateWhenRinging.isChecked() ? 1 : 0);
} else if (preference == mDtmfTone) {
Settings.System.putInt(getContentResolver(), Settings.System.DTMF_TONE_WHEN_DIALING,
mDtmfTone.isChecked() ? 1 : 0);

} else if (preference == mSoundEffects) {
if (mSoundEffects.isChecked()) {
mAudioManager.loadSoundEffects();
} else {
mAudioManager.unloadSoundEffects();
}
Settings.System.putInt(getContentResolver(), Settings.System.SOUND_EFFECTS_ENABLED,
mSoundEffects.isChecked() ? 1 : 0);

}

这里我们很容易的看清楚它的实例和点击监听，都是通过修改系统配置来进行操作的，那么这玩意到底在哪里整呢？

首先，触摸提示音，是对所有的view的点击时间都会有触发效果，那么我们看看View.java的类。

View.java有将近2万行，想研究的彻底很明显是不现实，或者说，不轻松的。那么我们搜素SOUND_EFFECTS_ENABLED 这个关键字

/**
* View flag indicating whether this view should have sound effects enabled
* for events such as clicking and touching.
*/
public static final int SOUND_EFFECTS_ENABLED = 0x08000000;

看注释，意思是是否启动声音效果。

/**
* Set whether this view should have sound effects enabled for events such as
* clicking and touching.
*
* <p>You may wish to disable sound effects for a view if you already play sounds,
* for instance, a dial key that plays dtmf tones.
*
* @param soundEffectsEnabled whether sound effects are enabled for this view.
* @see #isSoundEffectsEnabled()
* @see #playSoundEffect(int)
* @attr ref android.R.styleable#View_soundEffectsEnabled
*/
public void setSoundEffectsEnabled(boolean soundEffectsEnabled) {
setFlags(soundEffectsEnabled ? SOUND_EFFECTS_ENABLED: 0, SOUND_EFFECTS_ENABLED);
}

/**
* @return whether this view should have sound effects enabled for events such as
*     clicking and touching.
*
* @see #setSoundEffectsEnabled(boolean)
* @see #playSoundEffect(int)
* @attr ref android.R.styleable#View_soundEffectsEnabled
*/
@ViewDebug.ExportedProperty
public boolean isSoundEffectsEnabled() {
return SOUND_EFFECTS_ENABLED == (mViewFlags & SOUND_EFFECTS_ENABLED);
}

看到这2个方法我就有底了。很明显，我们要查看isSoundEffectsEnabled的调用关系。

/**
* Play a sound effect for this view.
*
* <p>The framework will play sound effects for some built in actions, such as
* clicking, but you may wish to play these effects in your widget,
* for instance, for internal navigation.
*
* <p>The sound effect will only be played if sound effects are enabled by the user, and
* {@link #isSoundEffectsEnabled()} is true.
*
* @param soundConstant One of the constants defined in {@link SoundEffectConstants}
*/
public void playSoundEffect(int soundConstant) {
if (mAttachInfo == null || mAttachInfo.mRootCallbacks == null || !isSoundEffectsEnabled()) {
return;
}
mAttachInfo.mRootCallbacks.playSoundEffect(soundConstant);
}

接着我们看谁调用了它，找到在AudioServeice.java中

/** @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) {
sendMsg(mAudioHandler, MSG_PLAY_SOUND_EFFECT, SENDMSG_QUEUE,
effectType, (int) (volume * 1000), null, 0);
}

写到这里，就是完了。接下来的需要，也就是对触摸音的资源文件的修改，它的位置在framework/base/data/sounds/effects 文件夹下。（同时这个文件夹的ogg下面也有一个相同的文件，这个我还不清楚）Effect_Tick.ogg。

对应的是在Android system/media/audio/ui Effect_Tick.ogg的文件。

想要修改它的话，可以在编译room的时候替换了它，或者push 一个新的同名文件。