本文主要是介绍Android8.1 MTK平台 SystemUI源码分析之 电池时钟刷新，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
SystemUI源码分析相关文章
Android8.1 MTK平台 SystemUI源码分析之 Notification流程
分析之前再贴一下 StatusBar 相关类图
电池图标刷新
从上篇的分析得到电池图标对应的布局为 SystemUI\src\com\android\systemui\BatteryMeterView.java
先从构造方法入手
public BatteryMeterView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);setOrientation(LinearLayout.HORIZONTAL);setGravity(Gravity.CENTER_VERTICAL | Gravity.START);TypedArray atts = context.obtainStyledAttributes(attrs, R.styleable.BatteryMeterView,defStyle, 0);final int frameColor = atts.getColor(R.styleable.BatteryMeterView_frameColor,context.getColor(R.color.meter_background_color));mDrawable = new BatteryMeterDrawableBase(context, frameColor);atts.recycle();mSettingObserver = new SettingObserver(new Handler(context.getMainLooper()));mSlotBattery = context.getString(com.android.internal.R.string.status_bar_battery);mBatteryIconView = new ImageView(context);mBatteryIconView.setImageDrawable(mDrawable);final MarginLayoutParams mlp = new MarginLayoutParams(getResources().getDimensionPixelSize(R.dimen.status_bar_battery_icon_width),getResources().getDimensionPixelSize(R.dimen.status_bar_battery_icon_height));mlp.setMargins(0, 0, 0,getResources().getDimensionPixelOffset(R.dimen.battery_margin_bottom));addView(mBatteryIconView, mlp);updateShowPercent();Context dualToneDarkTheme = new ContextThemeWrapper(context,Utils.getThemeAttr(context, R.attr.darkIconTheme));Context dualToneLightTheme = new ContextThemeWrapper(context,Utils.getThemeAttr(context, R.attr.lightIconTheme));mDarkModeBackgroundColor = Utils.getColorAttr(dualToneDarkTheme, R.attr.backgroundColor);mDarkModeFillColor = Utils.getColorAttr(dualToneDarkTheme, R.attr.fillColor);mLightModeBackgroundColor = Utils.getColorAttr(dualToneLightTheme, R.attr.backgroundColor);mLightModeFillColor = Utils.getColorAttr(dualToneLightTheme, R.attr.fillColor);// Init to not dark at all.onDarkChanged(new Rect(), 0, DarkIconDispatcher.DEFAULT_ICON_TINT);mUserTracker = new CurrentUserTracker(mContext) {@Overridepublic void onUserSwitched(int newUserId) {mUser = newUserId;getContext().getContentResolver().unregisterContentObserver(mSettingObserver);getContext().getContentResolver().registerContentObserver(Settings.System.getUriFor(SHOW_BATTERY_PERCENT), false, mSettingObserver,newUserId);}};
}
先说下 BatteryMeterView 继承自 LinearLayout，从上面的构造方法可以看出，我们看到的电池图标是由两部分组成的，
电量百分比(TextView)和电池等级(ImageView),构造方法主要做了如下几个操作
- 初始化电池等级icon，对应的drawable为 BatteryMeterDrawableBase，packages\apps\SettingsLib\src\com\android\settingslib\graph\BatteryMeterDrawableBase.java 将电池等级添加到父布局中
- 设置 Settings.System.SHOW_BATTERY_PERCENT 监听，当用户点击了显示电量百分比开关，则调用 updateShowPercent()方法在电池等级前添加电量百分比
- 通过onDarkChanged()设置默认的电池布局的主题色，当状态栏主题发生改变时，电池布局会做相应的更换(亮色和暗色切换)
在 PhoneStatusBarView 中添加了DarkReceiver监听，最终调用到 BatteryMeterView 的onDarkChanged()方法
修改百分比的字体颜色和电池等级的画笔颜色和背景颜色
// PhoneStatusBarView
@Override
protected void onAttachedToWindow() {super.onAttachedToWindow();// Always have Battery meters in the status bar observe the dark/light modes.Dependency.get(DarkIconDispatcher.class).addDarkReceiver(mBattery);
}@Override
protected void onDetachedFromWindow() {super.onDetachedFromWindow();Dependency.get(DarkIconDispatcher.class).removeDarkReceiver(mBattery);
}/BatteryMeterView
public void onDarkChanged(Rect area, float darkIntensity, int tint) {mDarkIntensity = darkIntensity;float intensity = DarkIconDispatcher.isInArea(area, this) ? darkIntensity : 0;int foreground = getColorForDarkIntensity(intensity, mLightModeFillColor,mDarkModeFillColor);int background = getColorForDarkIntensity(intensity, mLightModeBackgroundColor,mDarkModeBackgroundColor);mDrawable.setColors(foreground, background);setTextColor(foreground);
}
BatteryMeterDrawableBase 是一个自定义 Drawable，通过path来绘制电池图标，感兴趣的可自行研究
BatteryMeterView 中添加了电量改变监听，来看下 onBatteryLevelChanged()
@Override
public void onBatteryLevelChanged(int level, boolean pluggedIn, boolean charging) {mDrawable.setBatteryLevel(level);// M: In case battery protection, it stop charging, but still plugged, it will// also wrongly show the charging icon.mDrawable.setCharging(pluggedIn && charging);mLevel = level;updatePercentText();setContentDescription(getContext().getString(charging ? R.string.accessibility_battery_level_charging: R.string.accessibility_battery_level, level));
}@Override
public void onPowerSaveChanged(boolean isPowerSave) {mDrawable.setPowerSave(isPowerSave);
}
setBatteryLevel()根据当前 level/100f 计算百分比绘制path，setCharging()是否绘制充电中闪电形状图标
电池状态改变流程
我们都知道电池状态改变是通过广播的方式接受的(Intent.ACTION_BATTERY_CHANGED),搜索找到 BatteryControllerImpl
SystemUI\src\com\android\systemui\statusbar\policy\BatteryControllerImpl.java
@Override
public void onReceive(final Context context, Intent intent) {final String action = intent.getAction();if (action.equals(Intent.ACTION_BATTERY_CHANGED)) {if (mTestmode && !intent.getBooleanExtra("testmode", false)) return;mHasReceivedBattery = true;mLevel = (int)(100f* intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0)/ intent.getIntExtra(BatteryManager.EXTRA_SCALE, 100));mPluggedIn = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, 0) != 0;final int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS,BatteryManager.BATTERY_STATUS_UNKNOWN);mCharged = status == BatteryManager.BATTERY_STATUS_FULL;mCharging = mCharged || status == BatteryManager.BATTERY_STATUS_CHARGING;fireBatteryLevelChanged();}.......
}protected void fireBatteryLevelChanged() {synchronized (mChangeCallbacks) {final int N = mChangeCallbacks.size();for (int i = 0; i < N; i++) {mChangeCallbacks.get(i).onBatteryLevelChanged(mLevel, mPluggedIn, mCharging);}}
}
收到广播后通过 fireBatteryLevelChanged() 遍历回调监听，将状态参数发送。 BatteryMeterView实现了 BatteryStateChangeCallback,
收到改变监听 onBatteryLevelChanged()
android系统电池部分的驱动程序，继承了传统linux系统下的Power Supply驱动程序架构，Battery驱动程序通过Power Supply驱动程序生成相应的sys文件系统，
从而向用户空间提供电池各种属性的接口，然后遍历整个文件夹，查找各个能源供应设备的各种属性
Android的Linux 内核中的电池驱动会提供如下sysfs接口给framework：
/sys/class/power_supply/ac/onlineAC 电源连接状态
/sys/class/power_supply/usb/onlineUSB 电源连接状态
/sys/class/power_supply/battery/status 充电状态
/sys/class/power_supply/battery/health 电池状态
/sys/class/power_supply/battery/present 使用状态
/sys/class/power_supply/battery/capacity 电池 level
/sys/class/power_supply/battery/batt_vol 电池电压
/sys/class/power_supply/battery/batt_temp 电池温度
/sys/class/power_supply/battery/technology 电池技术
当供电设备的状态发生变化时，driver会更新这些文件，然后通过jni中的本地方法 android_server_BatteryService_update 向 java 层发送信息。
当监听到 power_supply 变化的消息后， nativeUpdate 函数就会重新读取以上sysfs文件获得当前状态。
而在用户层则是在 BatteryService.java 中通过广播的方式将电池相关的属性上报给上层app使用。
frameworks\base\services\core\java\com\android\server\BatteryService.java
BatteryService 在SystemServer.java 中创建，BatteryService 是在系统启动的时候就跑起来的，
为电池及充电相关的服务，主要作了如下几件事情: 监听 UEvent、读取sysfs 中的状态 、发出广播 Intent.ACTION_BATTERY_CHANGED 通知上层
BatteryService 的 start()中注册 BatteryListener，当battery配置改变的时候，调用 update()
private final class BatteryListener extends IBatteryPropertiesListener.Stub {@Override public void batteryPropertiesChanged(BatteryProperties props) {final long identity = Binder.clearCallingIdentity();try {BatteryService.this.update(props);} finally {Binder.restoreCallingIdentity(identity);}}
}private void update(BatteryProperties props) {synchronized (mLock) {if (!mUpdatesStopped) {mBatteryProps = props;// Process the new values.processValuesLocked(false);} else {mLastBatteryProps.set(props);}}
}private void processValuesLocked(boolean force) {boolean logOutlier = false;long dischargeDuration = 0;...sendIntentLocked();.....
}//发送 ACTION_BATTERY_CHANGED 广播
private void sendIntentLocked() {// Pack up the values and broadcast them to everyonefinal Intent intent = new Intent(Intent.ACTION_BATTERY_CHANGED);intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY| Intent.FLAG_RECEIVER_REPLACE_PENDING);int icon = getIconLocked(mBatteryProps.batteryLevel);intent.putExtra(BatteryManager.EXTRA_SEQUENCE, mSequence);intent.putExtra(BatteryManager.EXTRA_STATUS, mBatteryProps.batteryStatus);intent.putExtra(BatteryManager.EXTRA_HEALTH, mBatteryProps.batteryHealth);intent.putExtra(BatteryManager.EXTRA_PRESENT, mBatteryProps.batteryPresent);intent.putExtra(BatteryManager.EXTRA_LEVEL, mBatteryProps.batteryLevel);intent.putExtra(BatteryManager.EXTRA_SCALE, BATTERY_SCALE);intent.putExtra(BatteryManager.EXTRA_ICON_SMALL, icon);intent.putExtra(BatteryManager.EXTRA_PLUGGED, mPlugType);intent.putExtra(BatteryManager.EXTRA_VOLTAGE, mBatteryProps.batteryVoltage);intent.putExtra(BatteryManager.EXTRA_TEMPERATURE, mBatteryProps.batteryTemperature);intent.putExtra(BatteryManager.EXTRA_TECHNOLOGY, mBatteryProps.batteryTechnology);intent.putExtra(BatteryManager.EXTRA_INVALID_CHARGER, mInvalidCharger);intent.putExtra(BatteryManager.EXTRA_MAX_CHARGING_CURRENT, mBatteryProps.maxChargingCurrent);intent.putExtra(BatteryManager.EXTRA_MAX_CHARGING_VOLTAGE, mBatteryProps.maxChargingVoltage);intent.putExtra(BatteryManager.EXTRA_CHARGE_COUNTER, mBatteryProps.batteryChargeCounter);mHandler.post(new Runnable() {@Overridepublic void run() {ActivityManager.broadcastStickyIntent(intent, UserHandle.USER_ALL);}});
}
读取电池状态 cat /sys/class/power_supply/battery/uevent
时钟图标刷新
从 status_bar.xml 中看到时钟是一个自定义view， com.android.systemui.statusbar.policy.Clock
查看 Clock 源码知道继承自 TextView，时间内容更新通过setText()，通过监听如下5种广播 修改时间显示
@Override
protected void onAttachedToWindow() {super.onAttachedToWindow();if (!mAttached) {mAttached = true;IntentFilter filter = new IntentFilter();filter.addAction(Intent.ACTION_TIME_TICK);filter.addAction(Intent.ACTION_TIME_CHANGED);filter.addAction(Intent.ACTION_TIMEZONE_CHANGED);filter.addAction(Intent.ACTION_CONFIGURATION_CHANGED);filter.addAction(Intent.ACTION_USER_SWITCHED);getContext().registerReceiverAsUser(mIntentReceiver, UserHandle.ALL, filter,null, Dependency.get(Dependency.TIME_TICK_HANDLER));Dependency.get(TunerService.class).addTunable(this, CLOCK_SECONDS,StatusBarIconController.ICON_BLACKLIST);SysUiServiceProvider.getComponent(getContext(), CommandQueue.class).addCallbacks(this);if (mShowDark) {Dependency.get(DarkIconDispatcher.class).addDarkReceiver(this);}}// NOTE: It's safe to do these after registering the receiver since the receiver always runs// in the main thread, therefore the receiver can't run before this method returns.// The time zone may have changed while the receiver wasn't registered, so update the TimemCalendar = Calendar.getInstance(TimeZone.getDefault());// Make sure we update to the current timeupdateClock();updateShowSeconds();
}
可以看到 mIntentReceiver 监听了5种类型的action
Intent.ACTION_TIME_TICK 时钟频率，1分钟一次
Intent.ACTION_TIME_CHANGED 时钟改变，用户在设置中修改了设置时间选项
Intent.ACTION_TIMEZONE_CHANGED 时区改变，用户在设置中修改了选择时区
Intent.ACTION_CONFIGURATION_CHANGED 系统配置改变，如修改系统语言、系统屏幕方向发生改变
Intent.ACTION_USER_SWITCHED 切换用户，机主或其它访客之间切换
我们看到系统设置界面中的 使用24小时制 开关，点击后时间会立马改变显示，就是通过发送 ACTION_TIME_CHANGED 广播，
携带 EXTRA_TIME_PREF_24_HOUR_FORMAT 参数 ，下面是核心代码
vendor\mediatek\proprietary\packages\apps\MtkSettings\src\com\android\settings\datetime\TimeFormatPreferenceController.java
private void set24Hour(boolean is24Hour) {Settings.System.putString(mContext.getContentResolver(),Settings.System.TIME_12_24,is24Hour ? HOURS_24 : HOURS_12);
}private void timeUpdated(boolean is24Hour) {Intent timeChanged = new Intent(Intent.ACTION_TIME_CHANGED);int timeFormatPreference =is24Hour ? Intent.EXTRA_TIME_PREF_VALUE_USE_24_HOUR: Intent.EXTRA_TIME_PREF_VALUE_USE_12_HOUR;timeChanged.putExtra(Intent.EXTRA_TIME_PREF_24_HOUR_FORMAT, timeFormatPreference);mContext.sendBroadcast(timeChanged);
}
回到 Clock.java 中，发现 EXTRA_TIME_PREF_24_HOUR_FORMAT 并没有被用上，继续深究代码
final void updateClock() {if (mDemoMode) return;mCalendar.setTimeInMillis(System.currentTimeMillis());setText(getSmallTime());setContentDescription(mContentDescriptionFormat.format(mCalendar.getTime()));
}
收到广播最终都会调用 updateClock()，可以看到真正设置时间是通过 getSmallTime() 这个核心方法
private final CharSequence getSmallTime() {Context context = getContext();boolean is24 = DateFormat.is24HourFormat(context, ActivityManager.getCurrentUser());LocaleData d = LocaleData.get(context.getResources().getConfiguration().locale);final char MAGIC1 = '\uEF00';final char MAGIC2 = '\uEF01';SimpleDateFormat sdf;String format = mShowSeconds? is24 ? d.timeFormat_Hms : d.timeFormat_hms: is24 ? d.timeFormat_Hm : d.timeFormat_hm;if (!format.equals(mClockFormatString)) {mContentDescriptionFormat = new SimpleDateFormat(format);/** Search for an unquoted "a" in the format string, so we can* add dummy characters around it to let us find it again after* formatting and change its size.*/if (mAmPmStyle != AM_PM_STYLE_NORMAL) {int a = -1;boolean quoted = false;for (int i = 0; i < format.length(); i++) {char c = format.charAt(i);if (c == '\'') {quoted = !quoted;}if (!quoted && c == 'a') {a = i;break;}}if (a >= 0) {// Move a back so any whitespace before AM/PM is also in the alternate size.final int b = a;while (a > 0 && Character.isWhitespace(format.charAt(a-1))) {a--;}format = format.substring(0, a) + MAGIC1 + format.substring(a, b)+ "a" + MAGIC2 + format.substring(b + 1);}}mClockFormat = sdf = new SimpleDateFormat(format);mClockFormatString = format;} else {sdf = mClockFormat;}String result = sdf.format(mCalendar.getTime());if (mAmPmStyle != AM_PM_STYLE_NORMAL) {int magic1 = result.indexOf(MAGIC1);int magic2 = result.indexOf(MAGIC2);if (magic1 >= 0 && magic2 > magic1) {SpannableStringBuilder formatted = new SpannableStringBuilder(result);if (mAmPmStyle == AM_PM_STYLE_GONE) {formatted.delete(magic1, magic2+1);} else {if (mAmPmStyle == AM_PM_STYLE_SMALL) {CharacterStyle style = new RelativeSizeSpan(0.7f);formatted.setSpan(style, magic1, magic2,Spannable.SPAN_EXCLUSIVE_INCLUSIVE);}formatted.delete(magic2, magic2 + 1);formatted.delete(magic1, magic1 + 1);}return formatted;}}return result;}
方法有点长，我们挑主要的分析一下，DateFormat.is24HourFormat() 最终通过读取 Settings.System.TIME_12_24值，
这个值正好在上面的 TimeFormatPreferenceController 中点击24小时开关是改变，如果这个值为null，则通过获取本地时间
Local 来获取当前时间格式，如果等于24则返回true，该方法的源码可在AS中点进去查看，此处就不贴了。
LocaleData 是一个时间格式管理类，在 DateUtils.java 和 SimpleDateFormat.java 中都频繁使用
接下来获取到的 format 为 d.timeFormat_Hm， 设置给 SimpleDateFormat(d.timeFormat_Hm)
String result = sdf.format(mCalendar.getTime());就是当前需要显示的时间，此处还需要做一下格式化
mAmPmStyle 是通过构造函数自定义属性赋值的，xml中并没有赋值，取默认值 AM_PM_STYLE_GONE，走这段代码
formatted.delete(magic1, magic2+1); 去除多余的 ‘\uEF00’ 和 ‘\uEF01’，最终显示的就是 formatted。
参考文章
https://blog.csdn.net/weilaideta/article/details/51760434
https://blog.csdn.net/W1107101310/article/details/80211885
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