MTK 关闭耳机调至最大音量时，提示损伤听力

android开发之耳机调至最大音量时，提示损伤听力

android开发之耳机调至最大音量时，提示损伤听力

通过提示语，我们可以查出，只要的逻辑代码是在framework/base/packages/SystemUI/src/com/android/systemui/SafetyWarningDialog.java

查看代码可知，在这个类的构造函数中，首先初始化了一个dialog

 public SafetyWarningDialog(Context context, AudioManager audioManager) {
        super(context);
        mContext = context;
        mAudioManager = audioManager;

        getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ERROR);
        setMessage(mContext.getString(com.android.internal.R.string.safe_media_volume_warning));
        setButton(DialogInterface.BUTTON_POSITIVE,
                mContext.getString(com.android.internal.R.string.yes), this);
        setButton(DialogInterface.BUTTON_NEGATIVE,
                mContext.getString(com.android.internal.R.string.no), (OnClickListener) null);
        setOnDismissListener(this);

        final IntentFilter filter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
        context.registerReceiver(mReceiver, filter);
    }

当用户做按键操作时，会调用相关的listener 函数，具体的代码实现如下：

  @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_VOLUME_UP && event.getRepeatCount() == ) {
            mNewVolumeUp = true;
        }
        return super.onKeyDown(keyCode, event);
    }

    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_VOLUME_UP && mNewVolumeUp
                && (System.currentTimeMillis() - mShowTime) > KEY_CONFIRM_ALLOWED_AFTER) {
            if (D.BUG) Log.d(TAG, "Confirmed warning via VOLUME_UP");
            mAudioManager.disableSafeMediaVolume();
            dismiss();
        }
        return super.onKeyUp(keyCode, event);
    }

    @Override
    public void onClick(DialogInterface dialog, int which) {
        mAudioManager.disableSafeMediaVolume();
    }

mAudioManager.disableSafeMediaVolume();   //关闭安全音量提

如果说平台需要，可以通过config xml配置，将config_safe_media_volume_enabled 置false 来关闭此功能