Android touch sound

Step:
1.Main menu->Settings->Sound->Enable "Touch sounds"
2.Main menu->Settings->Display->Brightness->Mark&Unmark "Adapt to lighting conditions"
3.Check the phone sound.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Actual result:
The phone will not feedback touch sounds when tap "Adapt to lighting conditions" in Brightness.

code:    
BrightnessDialog.java (base\packages\systemui\src\com\android\systemui\settings)

quick_settings_brightness_dialog.xml:
    <CheckBox android:id="@+id/brightness_mode"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="@string/brightness_adapt_checkbox_information"
                android:textAppearance="?android:attr/textAppearanceSmall"
                android:layout_marginTop="6dip"
                />

View.java

    public boolean performClick() {
        sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);
        ListenerInfo li = mListenerInfo;
        if (li != null && li.mOnClickListener != null) {
            playSoundEffect(SoundEffectConstants.CLICK);
            li.mOnClickListener.onClick(this);
            return true;
        }
        return false;
    }

   

touch 声音是View playSoundEffect() 发出的。  但是View的onClickListener 沒有設置的話， performClick() 是不會調用playSoundEffect（）的。

因为Brightness 的dialog的Checkbox 没有设置onClickListener ， 所以click的时候没有声音。
所以只要给checkBox 设置个一onClickListener 就会有touch sound了。

同理测试一个Button 如果没有设置onClickListener， click时也不会有touch sound。



另外：

ViewRootImpl.java

    public void playSoundEffect(int effectId) {
        checkThread();
        if (mMediaDisabled) {
            return;
        }
        try {
            final AudioManager audioManager = getAudioManager();
            switch (effectId) {
                case SoundEffectConstants.CLICK:
                    audioManager.playSoundEffect(AudioManager.FX_KEY_CLICK);
                    return;

AudioManager.java

    public void  playSoundEffect(int effectType) {
        if (effectType < 0 || effectType >= NUM_SOUND_EFFECTS) {
            return;
        }
        if (!querySoundEffectsEnabled()) {
            return;
        }
        IAudioService service = getService();
        try {
            service.playSoundEffect(effectType);
        } catch (RemoteException e) {
            Log.e(TAG, "Dead object in playSoundEffect"+e);
        }
    }
 
    private boolean querySoundEffectsEnabled() {
        return Settings.System.getInt(mContext.getContentResolver(), Settings.System.SOUND_EFFECTS_ENABLED, 0) != 0;
    }

//当settings 的touch sounds 关闭后，就没有click的声音了。