Android BatteryStatsHelper深入理解(and5.1)

Log.e(\ continue; }

if (\ continue; } } final UserHandle userHandle = new UserHandle(UserHandle.getUserId(sipper.getUid()));

final BatteryEntry entry = new BatteryEntry(getActivity(), mHandler, mUm, sipper);

final Drawable badgedIcon = mUm.getBadgedIconForUser(entry.getIcon(), userHandle); final CharSequence contentDescription = mUm.getBadgedLabelForUser(entry.getLabel(), userHandle);

final PowerGaugePreference pref = new PowerGaugePreference(getActivity(), badgedIcon, contentDescription, entry);

final double percentOfMax = (sipper.value * 100) / mStatsHelper.getMaxPower(); sipper.percent = percentOfTotal; pref.setTitle(entry.getLabel()); pref.setOrder(i + 1);

pref.setPercent(percentOfMax, percentOfTotal); if (sipper.uidObj != null) {

pref.setKey(Integer.toString(sipper.uidObj.getUid())); }

addedSome = true;

mAppListGroup.addPreference(pref);

if (mAppListGroup.getPreferenceCount() > (MAX_ITEMS_TO_LIST + 1)) { break; } } }

if (!addedSome) {//如果走到这里会显示\没有电池数据\，要么power_profile.xml没有配置，要么每项都continue

addNotAvailableMessage(); }

BatteryEntry.startRequestQueue(); }

碰到一个问题当电池电量到90%，拔去usb线，settings会显示“没有电池使用数据”，带着这个问题，我们再来看看BatteryStatsImpl：

我们先来看看BatteryStatsHelper中refreshStats函数中的一段代码，如何统计mTotalPower，先会计算一个mComputedPower，会把每个usage的power累计相加，然后下面还有一段代码，mStats.getLowDischargeAmountSinceCharge是什么意思呢？带着这个问题再去看BatteryStatsImpl的代码。 [java] view plain copy

public void refreshStats(int statsType, SparseArray asUsers, long rawRealtimeUs, long rawUptimeUs) { 。。。。。。。。。。。。

mTotalPower = mComputedPower;

if (mStats.getLowDischargeAmountSinceCharge() > 1) {// if (mMinDrainedPower > mComputedPower) {

double amount = mMinDrainedPower - mComputedPower; mTotalPower = mMinDrainedPower;

addEntryNoTotal(BatterySipper.DrainType.UNACCOUNTED, 0, amount); } else if (mMaxDrainedPower < mComputedPower) {

double amount = mComputedPower - mMaxDrainedPower;

addEntryNoTotal(BatterySipper.DrainType.OVERCOUNTED, 0, amount); } }

Collections.sort(mUsageList); }

先看BatteryStatsImpl中getLowDischargeAmountSinceCharge函数，直接从代码中找哪里改变了这个变量mLowDischargeAmountSinceCharge [java] view plain copy @Override

public int getLowDischargeAmountSinceCharge() { synchronized(this) {

int val = mLowDischargeAmountSinceCharge;

if (mOnBattery && mDischargeCurrentLevel < mDischargeUnplugLevel) { val += mDischargeUnplugLevel-mDischargeCurrentLevel-1; }

return val; } }

发现在setOnBatteryLocked函数中会改变其值，而setOnBatteryLocked函数是有BatteryService调用，只有当充电方式改变才会掉，而我们这段代码代表，只有插上usb线会调用，level代表当前电量，mDischargeUnplugLevel代表上一次拔去usb线的电量，这就代表上次拔去usb线后，电量level减少了，就是耗电了，在这次充电的时候把之前的耗电统计下，放在mLowDischargeAmountSinceCharge 和mHighDischargeAmountSinceCharge 这两个变量中，这两个变量差1，就是有一个误差的范围而已。

[java] view plain copy

void setOnBatteryLocked(final long mSecRealtime, final long mSecUptime, final boolean onBattery,

final int oldStatus, final int level) { else {

mOnBattery = mOnBatteryInternal = onBattery; pullPendingStateUpdatesLocked();

mHistoryCur.batteryLevel = (byte)level;

mHistoryCur.states |= HistoryItem.STATE_BATTERY_PLUGGED_FLAG; if (DEBUG_HISTORY) Slog.v(TAG, \ + Integer.toHexString(mHistoryCur.states)); addHistoryRecordLocked(mSecRealtime, mSecUptime); mDischargeCurrentLevel = mDischargePlugLevel = level;

if (level < mDischargeUnplugLevel) {//level代表当前电量，mDischargeUnplugLevel代表上一次拔去usb线的电量

mLowDischargeAmountSinceCharge += mDischargeUnplugLevel-level-1;//累计消耗的电量

mHighDischargeAmountSinceCharge += mDischargeUnplugLevel-level; }

updateDischargeScreenLevelsLocked(screenOn, screenOn); updateTimeBasesLocked(false, !screenOn, uptime, realtime); mNumChargeStepDurations = 0; mLastChargeStepLevel = level; mMaxChargeStepLevel = level; mLastChargeStepTime = -1;

mInitStepMode = mCurStepMode; mModStepMode = 0; }

现在我们再来看看getLowDischargeAmountSinceCharge函数。 [java] view plain copy @Override

public int getLowDischargeAmountSinceCharge() { synchronized(this) {

int val = mLowDischargeAmountSinceCharge;

if (mOnBattery && mDischargeCurrentLevel < mDischargeUnplugLevel) {//表示现在正在用电状态，mDischargeCurrentLevel 变量代表用电的时候的电量，会时时更新，mDischargeUnplugLevel代表上一次拔去usb线的一个电量，也就是最近的一次消耗电量 val += mDiscwww.sm136.comhargeUnplugLevel-mDischargeCurrentLevel-1; }

return val; } }

最近一次的消耗电量加上之前累计的消耗电量就是总的消耗电量了。 下面看看几个关键变量

[java] view plain copy

void setOnBatteryLocked(final long mSecRealtime, final long mSecUptime, final boolean onBattery,

final int oldStatus, final int level) { boolean doWrite = false;

Message m = mHandler.obtainMessage(MSG_REPORT_POWER_CHANGE); m.arg1 = onBattery ? 1 : 0; mHandler.sendMessage(m);

final long uptime = mSecUptime * 1000; final long realtime = mSecRealtime * 1000;

final boolean screenOn = mScreenState == Display.STATE_ON; if (onBattery) { 。。。。。。。。。。

addHistoryRecordLocked(mSecRealtime, mSecUptime);

mDischargeCurrentLevel = mDischargeUnplugLevel = level;//刚拔去usb线的时候统计下mDischargeCurrentLevel和mDischargeUnplugLevel值 if (screenOn) {

mDischargeScreenOnUnplugLevel = level; mDischargeScreenOffUnplugLevel = 0; } else {

mDischargeScreenOnUnplugLevel = 0; mDischargeScreenOffUnplugLevel = level; }

mDischargeAmountScreenOn = 0; mDischargeAmountScreenOff = 0;

updateTimeBasesLocked(true, !screenOn, uptime, realtime); } else {

mOnBattery = mOnBatteryInternal = onBattery; pullPendingStateUpdatesLocked();

mHistoryCur.batteryLevel = (byte)level;

mHistoryCur.states |= HistoryItem.STATE_BATTERY_PLUGGED_FLAG; if (DEBUG_HISTORY) Slog.v(TAG, \ + Integer.toHexString(mHistoryCur.states)); addHistoryRecordLocked(mSecRealtime, mSecUptime);

mDischargeCurrentLevel = mDischargePlugLevel = level;//刚插上usb线的时候统计下mDischargeCurrentLevel和mDischargePlugLevel值

setBatteryState是BatteryService时时调的，而setOnBatteryLocked只有充电方式改变后才会调用。

[java] view plain copy

public void setBatteryState(int status, int health, int plugType, int level, int temp, int volt) { synchronized(this) {

final boolean onBattery = plugType == BATTERY_PLUGGED_NONE;