android开发笔记之电池低电处理

公司最近在搞个KMS，鼓励大家技术分享。好吧，我是一个好员工，积极响应领导的各种要求。但是，这个我不会写的，你可以说我没有分享精神，可以说我技术水平low，我就是不会写。如果公司一定要强制要求我写，我也一定是乱写凑数，这完全不能怪我，只能怪这个无情的世界，无情的季节，无情的………….。（请不要问我具体的原因，谢谢！）

但是，有一个好朋友，在上面发表了一个电池低电处理的文章，我看了一下，确实是说的非常清楚，只是是一个比较低版本的代码流程，我在 7.1的代码上看了一下，和他说的有一点出入，不过，这没有关系不影响我们来学习。

我可以不写，但是我们可以学习。

.java

.//base//core/java/com///.java

当电池电量少于我们配置的低电量警告值（）时，发送低电量通知，弹出低电量通知对话框。

.//base/core/res/res//.xml

<integer name="config_lowBatteryWarningLevel">15integer>

只我满足的条件就可以发送低电量通知：

private boolean shouldSendBatteryLowLocked() {final boolean plugged = mPlugType != BATTERY_PLUGGED_NONE;final boolean oldPlugged = mLastPlugType != BATTERY_PLUGGED_NONE;/* The ACTION_BATTERY_LOW broadcast is sent in these situations:* - is just un-plugged (previously was plugged) and battery level is*   less than or equal to WARNING, or* - is not plugged and battery level falls to WARNING boundary*   (becomes <= mLowBatteryWarningLevel).*/
        return !plugged&& mBatteryProps.batteryStatus != BatteryManager.BATTERY_STATUS_UNKNOWN&& mBatteryProps.batteryLevel <= mLowBatteryWarningLevel&& (oldPlugged || mLastBatteryLevel > mLowBatteryWarningLevel);}

发送低电量通知.：

private void processValuesLocked(boolean force)if (shouldSendBatteryLowLocked()) {mSentLowBatteryBroadcast = true;mHandler.post(new Runnable() {@Overridepublic void run() {Intent statusIntent = new Intent(Intent.ACTION_BATTERY_LOW);statusIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);}});

当电量为0时，发出关闭通知.OWN：

private void shutdownIfWeakChargerEmptySOCLocked() {if (mBatteryProps.batteryLevel == 0) {if (mInitiateShutdown) {if (ActivityManagerNative.isSystemReady()) {Intent intent = new Intent(Intent.ACTION_REQUEST_SHUTDOWN);intent.putExtra(Intent.EXTRA_KEY_CONFIRM, false);intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);mContext.startActivityAsUser(intent, UserHandle.CURRENT);}   

nings.java

.//base///src/com///power/nings.java

当电量低时，弹出低电量通知对话框：

private void showWarningNotification() {final int textRes = R.string.battery_low_percent_format;final String percentage = NumberFormat.getPercentInstance().format((double) mBatteryLevel / 100.0);final Notification.Builder nb = new Notification.Builder(mContext).setSmallIcon(R.drawable.ic_power_low)// Bump the notification when the bucket dropped..setWhen(mBucketDroppedNegativeTimeMs).setShowWhen(false).setContentTitle(mContext.getString(R.string.battery_low_title)).setContentText(mContext.getString(textRes, percentage)).setOnlyAlertOnce(true).setDeleteIntent(pendingBroadcast(ACTION_DISMISSED_WARNING)).setPriority(Notification.PRIORITY_MAX).setVisibility(Notification.VISIBILITY_PUBLIC).setColor(mContext.getColor(com.android.internal.R.color.battery_saver_mode_color));if (hasBatterySettings()) {nb.setContentIntent(pendingBroadcast(ACTION_SHOW_BATTERY_SETTINGS));}nb.addAction(0,mContext.getString(R.string.battery_saver_start_action),pendingBroadcast(ACTION_START_SAVER));if (mPlaySound) {attachLowBatterySound(nb);mPlaySound = false;}SystemUI.overrideNotificationAppName(mContext, nb);mNoMan.notifyAsUser(TAG_NOTIFICATION, R.id.notification_power, nb.build(), UserHandle.ALL);}

并播放低电量声音：

private void attachLowBatterySound(Notification.Builder b) {final ContentResolver cr = mContext.getContentResolver();final int silenceAfter = Settings.Global.getInt(cr,Settings.Global.LOW_BATTERY_SOUND_TIMEOUT, 0);final long offTime = SystemClock.elapsedRealtime() - mScreenOffTime;if (silenceAfter > 0&& mScreenOffTime > 0&& offTime > silenceAfter) {Slog.i(TAG, "screen off too long (" + offTime + "ms, limit " + silenceAfter+ "ms): not waking up the user with low battery sound");return;}if (DEBUG) {Slog.d(TAG, "playing low battery sound. pick-a-doop!"); // WOMP-WOMP is deprecated}if (Settings.Global.getInt(cr, Settings.Global.POWER_SOUNDS_ENABLED, 1) == 1) {final String soundPath = Settings.Global.getString(cr,Settings.Global.LOW_BATTERY_SOUND);if (soundPath != null) {final Uri soundUri = Uri.parse("file://" + soundPath);if (soundUri != null) {b.setSound(soundUri, AUDIO_ATTRIBUTES);if (DEBUG) Slog.d(TAG, "playing sound " + soundUri);}}}}

我们一般在配置文件中设置低电量的声音文件和超时时间：

.//base///res//.xml

<string name="def_low_battery_sound" translatable="false">/system/media/audio/ui/LowBattery.oggstring>
public void init() {// Register for Intent broadcasts for...IntentFilter filter = new IntentFilter();filter.addAction(Intent.ACTION_BATTERY_CHANGED);filter.addAction(Intent.ACTION_SCREEN_OFF);filter.addAction(Intent.ACTION_SCREEN_ON);filter.addAction(Intent.ACTION_USER_SWITCHED);filter.addAction(PowerManager.ACTION_POWER_SAVE_MODE_CHANGING);filter.addAction(PowerManager.ACTION_POWER_SAVE_MODE_CHANGED);mContext.registerReceiver(this, filter, null, mHandler);}@Overridepublic void onReceive(Context context, Intent intent) {String action = intent.getAction();if (action.equals(Intent.ACTION_BATTERY_CHANGED)) {final int oldBatteryLevel = mBatteryLevel;mBatteryLevel = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 100);final int oldBatteryStatus = mBatteryStatus;mBatteryStatus = intent.getIntExtra(BatteryManager.EXTRA_STATUS,BatteryManager.BATTERY_STATUS_UNKNOWN);final int oldPlugType = mPlugType;mPlugType = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, 1);final int oldInvalidCharger = mInvalidCharger;mInvalidCharger = intent.getIntExtra(BatteryManager.EXTRA_INVALID_CHARGER, 0);final boolean plugged = mPlugType != 0;final boolean oldPlugged = oldPlugType != 0;int oldBucket = findBatteryLevelBucket(oldBatteryLevel);int bucket = findBatteryLevelBucket(mBatteryLevel);mWarnings.update(mBatteryLevel, bucket, mScreenOffTime);if (oldInvalidCharger == 0 && mInvalidCharger != 0) {mWarnings.showInvalidChargerWarning();return;} else if (oldInvalidCharger != 0 && mInvalidCharger == 0) {mWarnings.dismissInvalidChargerWarning();} else if (mWarnings.isInvalidChargerWarningShowing()) {return;}boolean isPowerSaver = mPowerManager.isPowerSaveMode();if (!plugged&& !isPowerSaver&& (bucket < oldBucket || oldPlugged)&& mBatteryStatus != BatteryManager.BATTERY_STATUS_UNKNOWN&& bucket < 0) {// only play SFX when the dialog comes up or the bucket changesfinal boolean playSound = bucket != oldBucket || oldPlugged;mWarnings.showLowBatteryWarning(playSound);

可见，现在弹出低电量通知对话框是接受广播.ED来实现的。