PowerManagerService sensor

默认分类 2010-12-24 14:34:55 阅读144 评论1   字号：大中小 订阅

frameworks/base/services/java/com/android/server/PowerManagerService.java

首先通过sensormanager来获得service 这里以light sensor为例

 void systemReady() {
        mSensorManager = new SensorManager(mHandlerThread.getLooper());
        mProximitySensor = mSensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
        // don't bother with the light sensor if auto brightness is handled in hardware
        if (mUseSoftwareAutoBrightness) {
            mLightSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
            enableLightSensor(true);
        }
这里使用enableLightSensor来确定是不是lightsensor有效

    private void enableLightSensor(boolean enable) {
        if (mDebugLightSensor) {
            Slog.d(TAG, "enableLightSensor " + enable);
        }
        if (mSensorManager != null && mLightSensorEnabled != enable) {
            mLightSensorEnabled = enable;
            // clear calling identity so sensor manager battery stats are accurate
            long identity = Binder.clearCallingIdentity();
            try {
                if (enable) {
                    mSensorManager.registerListener(mLightListener, mLightSensor,
                            SensorManager.SENSOR_DELAY_NORMAL);
                } else {
                    mSensorManager.unregisterListener(mLightListener);
                    mHandler.removeCallbacks(mAutoBrightnessTask);
                }
            } finally {
                Binder.restoreCallingIdentity(identity);
            }
        }
    }
如果有效就注册一下监听事件 监听mLightListener事件响应

    SensorEventListener mLightListener = new SensorEventListener() {
        public void onSensorChanged(SensorEvent event) {
            synchronized (mLocks) {
                // ignore light sensor while screen is turning off
                if (isScreenTurningOffLocked()) {
                    return;
                }

                int value = (int)event.values[0];
                long milliseconds = SystemClock.elapsedRealtime();
                if (mDebugLightSensor) {
                    Slog.d(TAG, "onSensorChanged: light value: " + value);
                }
                mHandler.removeCallbacks(mAutoBrightnessTask);
                if (mLightSensorValue != value) {
                    if (mLightSensorValue == -1 ||
                            milliseconds < mLastScreenOnTime + mLightSensorWarmupTime) {
                        // process the value immediately if screen has just turned on
                        lightSensorChangedLocked(value);
                    } else {
                        // delay processing to debounce the sensor
                        mLightSensorPendingValue = value;
                        mHandler.postDelayed(mAutoBrightnessTask, LIGHT_SENSOR_DELAY);
                    }
                } else {
                    mLightSensorPendingValue = -1;
                }
            }
        }

        public void onAccuracyChanged(Sensor sensor, int accuracy) {
            // ignore
        }
    };
看到onsensorchanged事件了吧 这里做事情 用handler来实现一个延迟消息发送 标准用法 执行什么样的任务呢？继续看

    private Runnable mAutoBrightnessTask = new Runnable() {
        public void run() {
            synchronized (mLocks) {
                int value = (int)mLightSensorPendingValue;
                if (value >= 0) {
                    mLightSensorPendingValue = -1;
                    lightSensorChangedLocked(value);
                }
            }
        }
    };
然后lightSensorChangedLocked函数里就是各个具体的灯的控制了 比如 mButtonLight.setBrightness(buttonValue);等等 还有很多灯的动画 比如呼吸灯之类的 目前的LightAnimator好像只有一种就是隔几秒闪一下。。。