怎么調(diào)節(jié)android屏幕亮度的辦法

2020-02-21 17:38:55

字體：大中小

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今天小編跟大家分享一下怎么調(diào)節(jié)android屏幕亮度的辦法，感興趣的朋友跟小編一起來了解一下吧！

屏幕亮度自動調(diào)節(jié)：
主要是從Sensor分析之中分離出來分析LIGHT 光線感應(yīng)器，因此就分析一下自動調(diào)節(jié)屏幕亮度（手機隨著光線的強度自我調(diào)節(jié)，也就是在亮的光線下屏幕自動調(diào)亮一些，暗的時候就自動調(diào)暗一些，省得光線對眼睛有刺激）.....

??? (本人從歷經(jīng)挫折才大概了解流程)，現(xiàn)在就開始講一下流程，如果有不對地方希望牛人指出來。。。

??? 先從Sttings入手吧，在diaplay中有屏幕亮度調(diào)節(jié)，有一個進度調(diào)，上面有一個checkbox（自動調(diào)節(jié)屏幕亮度的），

那么我們當(dāng)然去找settings下的文件開始看了，先找到
DiaplaySettings.java文件以及display_setting.xml文件，display_setting.xml里面能找到相應(yīng)的組件，但是在DiaplaySettings.java文件中卻不能找到調(diào)用相應(yīng)組件的代碼，

那么我們再到settings中去找，能找到BrightnessPreference.java文件，沒錯這個文件就是自動調(diào)節(jié)亮度的文件，我們先看看代碼：
構(gòu)造函數(shù)中有mAutomaticAvailable = context.getResources().getBoolean(com.android.internal.R.bool.config_automatic_brightness_available);
開始以為mAutomaticAvailabl的值（為true，在config.xml中）是判斷是否自動調(diào)節(jié)亮度，因為在我跟進到PowerManagerService.java中，在initInThread() 中
? mUseSoftwareAutoBrightness = resources.getBoolean(
??????????????? com.android.internal.R.bool.config_automatic_brightness_available);

??????? if (mUseSoftwareAutoBrightness) {
??????????? mAutoBrightnessLevels = resources.getIntArray(
??????????????????? com.android.internal.R.array.config_autoBrightnessLevels);//得到自動化調(diào)節(jié)的值調(diào)用 getAutoBrightnessValue(int sensorValue, int[] values) 方法
??????????? mLcdBacklightValues = resources.getIntArray(
??????????????????? com.android.internal.R.array.config_autoBrightnessLcdBacklightValues);
??????????? mButtonBacklightValues = resources.getIntArray(
??????????????????? com.android.internal.R.array.config_autoBrightnessButtonBacklightValues);
??????????? mKeyboardBacklightValues = resources.getIntArray(。。。。。
。。。。。。這里看起來好像是當(dāng)mUseSoftwareAutoBrightness為true時就取得config.xml文件config_autoBrightnessLevels的值，再去根據(jù)光線自動調(diào)節(jié)，但是mAutomaticAvailabl的值只是說明有沒有自動調(diào)節(jié)屏幕的功能（比如說你將config.xml文件的config_automatic_brightness_available的值改為false，編譯替換framework-res.apk那么在屏幕亮度調(diào)節(jié)中將沒有自動調(diào)節(jié)的checkbox），這也能解釋構(gòu)造函數(shù)一開始就初始化mAutomaticAvailabl的值。

接下來在BrightnessPreference.java文件中有onProgressChanged，onStartTrackingTouch(SeekBar seekBar)，onStopTrackingTouch(SeekBar seekBar)方法，這些一看也能懂就不介紹了，在onBindDialogView(View view)方法中有
mCheckBox = (CheckBox)view.findViewById(R.id.automatic_mode);
??????? if (mAutomaticAvailable) {//當(dāng)有自動調(diào)節(jié)功能
??????????? mCheckBox.setOnCheckedChangeListener(this);//為checkbox添加監(jiān)聽事件
??????????? try {
??????????????? mOldAutomatic = Settings.System.getInt(getContext().getContentResolver(),
??????????????????????? Settings.System.SCREEN_BRIGHTNESS_MODE);
。。。。。。
主要看public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
??????? setMode(isChecked ? Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC
??????????????? : Settings.System.SCREEN_BRIGHTNESS_MODE_MANUAL);
??????? if (!isChecked) {
??????????? setBrightness(mSeekBar.getProgress() + MINIMUM_BACKLIGHT);
??????? }
??? }
這里才是你選擇自動調(diào)節(jié)亮度的checkbox，如果選擇則setMode（Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC）；并將數(shù)據(jù)存放到數(shù)據(jù)庫中。

這里是重點：這里有個數(shù)據(jù)庫，當(dāng)監(jiān)測到數(shù)據(jù)庫中的值發(fā)生改變時也就是變?yōu)镾ettings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC時，就會跳到
powerManagerService.java的initInThread()中ContentResolver resolver = mContext.getContentResolver();
??????? Cursor settingsCursor = resolver.query(Settings.System.CONTENT_URI, null,
??????????????? "(" + Settings.System.NAME + "=?) or ("
??????????????????????? + Settings.System.NAME + "=?) or ("
??????????????????????? + Settings.System.NAME + "=?) or ("
??????????????????????? + Settings.System.NAME + "=?) or ("
??????????????????????? + Settings.System.NAME + "=?) or ("
??????????????????????? + Settings.System.NAME + "=?) or ("
??????????????????????? + Settings.System.NAME + "=?)",
??????????????? new String[]{STAY_ON_WHILE_PLUGGED_IN, SCREEN_OFF_TIMEOUT, DIM_SCREEN, XEC_DLS_CONTROL,
??????????????????????? SCREEN_BRIGHTNESS_MODE, WINDOW_ANIMATION_SCALE, TRANSITION_ANIMATION_SCALE},
??????????????? null);
??????? mSettings = new ContentQueryMap(settingsCursor, Settings.System.NAME, true, mHandler);
??????? SettingsObserver settingsObserver = new SettingsObserver();
??????? mSettings.addObserver(settingsObserver);
數(shù)據(jù)庫中數(shù)據(jù)發(fā)生改變時觸發(fā)事件的發(fā)生。

在 powerManagerService.java的systemReady()（只在開機調(diào)用一次就不再調(diào)用）中
?if (mUseSoftwareAutoBrightness) {
??????????? Log.i("frist","frist="+"aaaa");
??????????? mLightSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
??????????? enableLightSensor(true);
??????? }
而mUseSoftwareAutoBrightness是在initInThread()線程中取得了true值，那么就到enableLightSensor(true);方法去看
?if (enable) {
??????????????????? mSensorManager.registerListener(mLightListener, mLightSensor,
??????????????????????????? SensorManager.SENSOR_DELAY_NORMAL);
??????????????? }
如果傳遞來的值為true也就是enable=true就監(jiān)聽而且用匹配屏幕方向變化的感應(yīng)SENSOR_DELAY_NORMAL。
再看mLightListener事件：SensorEventListener mLightListener = new SensorEventListener() {
??????? public void onSensorChanged(SensorEvent event) {
??????????? synchronized (mLocks) {
??????????????? int value = (int)event.values[0];//從event里面獲取當(dāng)前數(shù)據(jù)
??????????????? Log.i("value","value="+value);???????
??????????????? long milliseconds = SystemClock.elapsedRealtime();
??????????????? if (mDebugLightSensor) {
??????????????????? Slog.d(TAG, "onSensorChanged: light value: " + value);
??????????????? }
??????????????? mHandler.removeCallbacks(mAutoBrightnessTask);
??????????????? if (mLightSensorValue != value) {//mLightSensorValue是當(dāng)前的屏幕亮度
??????????????????? if (mLightSensorValue == -1 ||
??????????????????????????? milliseconds ??????????????????????? // process the value immediately if screen has just turned on
??????????????????????? lightSensorChangedLocked(value);
??????????????????? } else {
??????????????????????? // delay processing to debounce the sensor
??????????????????????? mLightSensorPendingValue = value;//mLightSensorPendingValue是準(zhǔn)備要設(shè)置的亮度
??????????????????????? mHandler.postDelayed(mAutoBrightnessTask, LIGHT_SENSOR_DELAY);//到mAutoBrightnessTask線程去完成自動調(diào)節(jié)
??????????????????? }
??????????????? } else {
??????????????????? mLightSensorPendingValue = -1;
??????????????? }
??????????? }
??????? }
當(dāng)前屏幕亮度肯定不等與-1，所以做else中的mHandler.postDelayed(mAutoBrightnessTask, LIGHT_SENSOR_DELAY)，那么我們再到mAutoBrightnessTask
線程看：private Runnable mAutoBrightnessTask = new Runnable() {
??????? public void run() {
??????????? synchronized (mLocks) {
??????????????? int value = (int)mLightSensorPendingValue;
??????????????? Log.i("mLightSensorPendingValue","mLightSensorPendingValue"+mLightSensorPendingValue);
??????????????? if (value >= 0) {
??????????????????? mLightSensorPendingValue = -1;
??????????????????? lightSensorChangedLocked(value);
??????????????? }
??????????? }
??????? }
??? };就是不斷的去調(diào)用lightSensorChangedLocked(value)
private void lightSensorChangedLocked(int value) {
。。。。。。。
if (mLightSensorValue != value) {
??????????? mLightSensorValue = value;
??????????? if ((mPowerState & BATTERY_LOW_BIT) == 0) {
??????????????? // Use light sensor value no matter it is in a dock or not.
??????????????? int lcdValue = getAutoBrightnessValue(
??????????????????????? value,
??????????????????????? mLcdBacklightValues);// 取得mLcdBacklightValues里面的值
??????????????? int buttonValue = getAutoBrightnessValue(value, mButtonBacklightValues);
??????????????? int keyboardValue;
??????????????? if (mKeyboardVisible) {
??????????????????? keyboardValue = getAutoBrightnessValue(value, mKeyboardBacklightValues);
??????????????? } else {
??????????????????? keyboardValue = 0;
??????????????? }
。。。
if (mAutoBrightessEnabled && mScreenBrightnessOverride ??????????????????? mScreenBrightness.setTargetLocked(lcdValue, AUTOBRIGHTNESS_ANIM_STEPS,
??????????????????????????? INITIAL_SCREEN_BRIGHTNESS, (int)mScreenBrightness.curValue);
??????????????? }
。。。。。
?? }