Android自动调整亮度，自动转屏和重力感应的设置
一）Setting相关处理
Settings->display->auto rotate(自动旋转屏幕)
/packages/apps/Settings/res/values/strings.xml
<string name="accelerometer_title">Auto-rotate screen</string>
packages/apps/Settings/res/xml/display_settings.xml
<CheckBoxPreference
android:key="accelerometer"
android:title="@string/accelerometer_title"/>
packages/apps/Settings/src/com/android/settings/DisplaySettings.java
mAccelerometer.setChecked(Settings.System.getInt( if (preference == mAccelerometer) {
getContentResolver(), Settings.System.putInt(getContentResolver(),
Settings.System.ACCELEROMETER_ROTATION, 0) != 0); Settings.System.ACCELEROMETER_ROTATION,
mAccelerometer.isChecked() ? 1 : 0);
Settings.System.ACCELEROMETER_ROTATION表示重力感应，横竖屏切换 }
frameworks/policies/base/phone/com/android/internal/policy/impl/PhoneWindowManager.java
void observe() {
ContentResolver resolver = mContext.getContentResolver();
resolver.registerContentObserver(Settings.System.getUriFor(
Settings.System.END_BUTTON_BEHAVIOR), false, this);
resolver.registerContentObserver(Settings.Secure.getUriFor(
Settings.Secure.INCALL_POWER_BUTTON_BEHAVIOR), false, this);
resolver.registerContentObserver(Settings.System.getUriFor(
Settings.System.ACCELEROMETER_ROTATION), false, this);
int accelerometerDefault = Settings.System.getInt(resolver,
Settings.System.ACCELEROMETER_ROTATION, DEFAULT_ACCELEROMETER_ROTATION);
if (mAccelerometerDefault != accelerometerDefault) {
mAccelerometerDefault = accelerometerDefault;
updateOrientationListene rLp();
}
MyOrientationListener mOrientationListener;
packages/apps/Phone/src/com/android/phone/AccelerometerListener.java
private void onSensorEvent(double x, double y, double z) {
。。。
setOrientation(orientation);
}
2）加速度（accelerometer）是否就是重力感应
自动调整亮度说明
自动调整亮度，即：当阳光很强时，由于外界亮度大，需要加亮屏幕，才能看清，否则觉得屏幕昏暗；当外界光线很弱时，屏幕只需要低一点的亮度就够看清了，否则觉得刺眼。
要启动自动调整亮度，
1）首先，必须配置config.xml
在frameworks/base/core/res/res/values/config.xml里面的配置项config_automatic_brightness_available设置为true，缺省是false
2）在第一步设置之后，Settings->display->亮度设置，界面上会多出一个“自动调整亮度”选择框，如果选择框打勾，则表示真正启动了自动亮度调整
以下是自动亮度调整的代码跟踪
PowerManagerService.java
systemReady方法里面代码片段是
if (mUseSoftwareAutoBrightne ss) {
if (mDebugLightSensor)
Log.d(TAG, "mUseSoftwareAutoBrightne ss=true");
mLightSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
enableLightSensor(true);
}
（mUseSoftwareAutoBrightne ss从frameworks/base/core/res/res/values/config.xml里面的配置项config_automatic_brightness_available获取，
如果为true，则调用enableLightSensor(true)；
enableLightSensor函数会调用
mSensorManager.registerListener(mLightListener, mLightSensor,
SensorManager.SENSOR_DELAY_NORMAL);
其中mSensorManager是PowerManagerService中的SensorManager对象成员变量，
mLightListener是注册的监听器类SensorEventListener对象，如果亮度变化，会触发其方法的调用，
mLightSensor是PowerManagerService中的LightSensor对象成员变量，代表光传感器。
SensorEventListener类定义如下
SensorEventListener mLightListener = new SensorEventListener() {
public void onSensorChanged(SensorEvent event) {
synchronized (mLocks) {
// ignore light sensor while screen is turning off
if (isScreenTurningOffLocked ()) {
Log.d(TAG, "ScreenTurningOffLocked, just return.");
return;
}
int value = (int)event.values[0]; //从event里面获取当前数据，亮度大概在0到二十几
long milliseconds = SystemClock.elapsedRealtime();
if (mDebugLightSensor) {
Log.d(TAG, "onSensorChanged: light value: " + value);
}
mHandler.removeCallbacks(mAutoBrightnessTask);
if (mLightSensorValue != value) { //mLightSensorValue是当前的屏幕亮度
if (mLightSensorValue == -1 ||
milliseconds < mLastScreenOnTime + mLightSensorWarmupTime) {
// process the value immediately if screen has just turned on
lightSensorChangedLocked (value); //屏幕刚刚打开
} else {
// delay processing to debounce the sensor
mLightSensorPendingValue = value; //mLightSensorPendingValue 是准备要设置的亮度
mHandler.postDelayed(mAutoBrightnessTask, LIGHT_SENSOR_DELAY); //在mAutoBrightnessTask任务里面延后处理
Settings->display->auto rotate(自动旋转屏幕)
/packages/apps/Settings/res/values/strings.xml
<string name="accelerometer_title">Auto-rotate screen</string>
packages/apps/Settings/res/xml/display_settings.xml
<CheckBoxPreference
android:key="accelerometer"
android:title="@string/accelerometer_title"/>
packages/apps/Settings/src/com/android/settings/DisplaySettings.java
mAccelerometer.setChecked(Settings.System.getInt( if (preference == mAccelerometer) {
getContentResolver(), Settings.System.putInt(getContentResolver(),
Settings.System.ACCELEROMETER_ROTATION, 0) != 0); Settings.System.ACCELEROMETER_ROTATION,
mAccelerometer.isChecked() ? 1 : 0);
Settings.System.ACCELEROMETER_ROTATION表示重力感应，横竖屏切换 }
二）自动转屏的实现
frameworks/policies/base/phone/com/android/internal/policy/impl/PhoneWindowManager.java
void observe() {
ContentResolver resolver = mContext.getContentResolver();
resolver.registerContentObserver(Settings.System.getUriFor(
Settings.System.END_BUTTON_BEHAVIOR), false, this);
resolver.registerContentObserver(Settings.Secure.getUriFor(
Settings.Secure.INCALL_POWER_BUTTON_BEHAVIOR), false, this);
resolver.registerContentObserver(Settings.System.getUriFor(
Settings.System.ACCELEROMETER_ROTATION), false, this);
int accelerometerDefault = Settings.System.getInt(resolver,
Settings.System.ACCELEROMETER_ROTATION, DEFAULT_ACCELEROMETER_ROTATION);
if (mAccelerometerDefault != accelerometerDefault) {
mAccelerometerDefault = accelerometerDefault;
updateOrientationListene rLp();
}
MyOrientationListener mOrientationListener;
packages/apps/Phone/src/com/android/phone/AccelerometerListener.java
private void onSensorEvent(double x, double y, double z) {
。。。
setOrientation(orientation);
}
2）加速度（accelerometer）是否就是重力感应
自动调整亮度说明
自动调整亮度，即：当阳光很强时，由于外界亮度大，需要加亮屏幕，才能看清，否则觉得屏幕昏暗；当外界光线很弱时，屏幕只需要低一点的亮度就够看清了，否则觉得刺眼。
要启动自动调整亮度，
1）首先，必须配置config.xml
在frameworks/base/core/res/res/values/config.xml里面的配置项config_automatic_brightness_available设置为true，缺省是false
2）在第一步设置之后，Settings->display->亮度设置，界面上会多出一个“自动调整亮度”选择框，如果选择框打勾，则表示真正启动了自动亮度调整
以下是自动亮度调整的代码跟踪
PowerManagerService.java
systemReady方法里面代码片段是
if (mUseSoftwareAutoBrightne ss) {
if (mDebugLightSensor)
Log.d(TAG, "mUseSoftwareAutoBrightne ss=true");
mLightSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
enableLightSensor(true);
}
（mUseSoftwareAutoBrightne ss从frameworks/base/core/res/res/values/config.xml里面的配置项config_automatic_brightness_available获取，
如果为true，则调用enableLightSensor(true)；
enableLightSensor函数会调用
mSensorManager.registerListener(mLightListener, mLightSensor,
SensorManager.SENSOR_DELAY_NORMAL);
其中mSensorManager是PowerManagerService中的SensorManager对象成员变量，
mLightListener是注册的监听器类SensorEventListener对象，如果亮度变化，会触发其方法的调用，
mLightSensor是PowerManagerService中的LightSensor对象成员变量，代表光传感器。
SensorEventListener类定义如下
SensorEventListener mLightListener = new SensorEventListener() {
public void onSensorChanged(SensorEvent event) {
synchronized (mLocks) {
// ignore light sensor while screen is turning off
if (isScreenTurningOffLocked ()) {
Log.d(TAG, "ScreenTurningOffLocked, just return.");
return;
}
int value = (int)event.values[0]; //从event里面获取当前数据，亮度大概在0到二十几
long milliseconds = SystemClock.elapsedRealtime();
if (mDebugLightSensor) {
Log.d(TAG, "onSensorChanged: light value: " + value);
}
mHandler.removeCallbacks(mAutoBrightnessTask);
if (mLightSensorValue != value) { //mLightSensorValue是当前的屏幕亮度
if (mLightSensorValue == -1 ||
milliseconds < mLastScreenOnTime + mLightSensorWarmupTime) {
// process the value immediately if screen has just turned on
lightSensorChangedLocked (value); //屏幕刚刚打开
} else {
// delay processing to debounce the sensor
mLightSensorPendingValue = value; //mLightSensorPendingValue 是准备要设置的亮度
mHandler.postDelayed(mAutoBrightnessTask, LIGHT_SENSOR_DELAY); //在mAutoBrightnessTask任务里面延后处理