SystemUI原始碼分析相關文章

Android8.1 SystemUI原始碼分析之 Notification流程

分析之前再貼一下 StatusBar 相關類圖

電池圖示重新整理

從上篇的分析得到電池圖示對應的佈局為 SystemUI\src\com\android\systemui\BatteryMeterView.java

先從構造方法入手

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) {
        @Override
        public void onUserSwitched(int newUserId) {
            mUser = newUserId;
            getContext().getContentResolver().unregisterContentObserver(mSettingObserver);
            getContext().getContentResolver().registerContentObserver(
                    Settings.System.getUriFor(SHOW_BATTERY_PERCENT), false, mSettingObserver,
                    newUserId);
        }
    };
}
 

先說下 BatteryMeterView 繼承自 LinearLayout，從上面的構造方法可以看出，我們看到的電池圖示是由兩部分組成的，

電量百分比(TextView)和電池等級(ImageView),構造方法主要做了如下幾個操作

1. 初始化電池等級icon，對應的drawable為 BatteryMeterDrawableBase，packages\apps\SettingsLib\src\com\android\settingslib\graph\BatteryMeterDrawableBase.java 將電池等級新增到父佈局中
2. 設定 Settings.System.SHOW_BATTERY_PERCENT 監聽，當用戶點選了顯示電量百分比開關，則呼叫 updateShowPercent()方法在電池等級前新增電量百分比
3. 通過onDarkChanged()設定預設的電池佈局的主題色，當狀態列主題發生改變時，電池佈局會做相應的更換(亮色和暗色切換)

在 PhoneStatusBarView 中添加了DarkReceiver監聽，最終呼叫到 BatteryMeterView 的onDarkChanged()方法

修改百分比的字型顏色和電池等級的畫筆顏色和背景顏色

////// 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 是一個自定義 Drawable，通過path來繪製電池圖示，感興趣的可自行研究

BatteryMeterView 中添加了電量改變監聽，來看下 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()根據當前 level/100f 計算百分比繪製path，setCharging()是否繪製充電中閃電形狀圖示

電池狀態改變流程

我們都知道電池狀態改變是通過廣播的方式接受的(Intent.ACTION_BATTERY_CHANGED),搜尋找到 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);
        }
    }
}

收到廣播後通過 fireBatteryLevelChanged() 遍歷回撥監聽，將狀態引數傳送。 BatteryMeterView實現了 BatteryStateChangeCallback,

收到改變監聽 onBatteryLevelChanged()

android系統電池部分的驅動程式，繼承了傳統linux系統下的Power Supply驅動程式架構，Battery驅動程式通過Power Supply驅動程式生成相應的sys檔案系統，

從而向用戶空間提供電池各種屬性的介面，然後遍歷整個資料夾，查詢各個能源供應裝置的各種屬性

Android的Linux 核心中的電池驅動會提供如下sysfs介面給framework：

/sys/class/power_supply/ac/onlineAC 電源連線狀態

/sys/class/power_supply/usb/onlineUSB 電源連線狀態

/sys/class/power_supply/battery/status 充電狀態

/sys/class/power_supply/battery/health 電池狀態

/sys/class/power_supply/battery/present 使用狀態

/sys/class/power_supply/battery/capacity 電池 level

/sys/class/power_supply/battery/batt_vol 電池電壓

/sys/class/power_supply/battery/batt_temp 電池溫度

/sys/class/power_supply/battery/technology 電池技術

當供電裝置的狀態發生變化時，driver會更新這些檔案，然後通過jni中的本地方法 android_server_BatteryService_update 向 java 層傳送資訊。

當監聽到 power_supply 變化的訊息後， nativeUpdate 函式就會重新讀取以上sysfs檔案獲得當前狀態。

而在使用者層則是在 BatteryService.java 中通過廣播的方式將電池相關的屬性上報給上層app使用。

frameworks\base\services\core\java\com\android\server\BatteryService.java

BatteryService 在SystemServer.java 中建立，BatteryService 是在系統啟動的時候就跑起來的，

為電池及充電相關的服務，主要作了如下幾件事情: 監聽 UEvent、讀取sysfs 中的狀態 、發出廣播 Intent.ACTION_BATTERY_CHANGED 通知上層

BatteryService 的 start()中註冊 BatteryListener，當battery配置改變的時候，呼叫 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();
    .....
}

//傳送 ACTION_BATTERY_CHANGED 廣播
private void sendIntentLocked() {
    //  Pack up the values and broadcast them to everyone
    final 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() {
        @Override
        public void run() {
            ActivityManager.broadcastStickyIntent(intent, UserHandle.USER_ALL);
        }
    });
}

讀取電池狀態 cat /sys/class/power_supply/battery/uevent

時鐘圖示重新整理

從 status_bar.xml 中看到時鐘是一個自定義view， com.android.systemui.statusbar.policy.Clock

檢視 Clock 原始碼知道繼承自 TextView，時間內容更新通過setText()，通過監聽如下5種廣播 修改時間顯示

@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 Time
    mCalendar = Calendar.getInstance(TimeZone.getDefault());

    // Make sure we update to the current time
    updateClock();
    updateShowSeconds();
}

可以看到 mIntentReceiver 監聽了5種類型的action

Intent.ACTION_TIME_TICK 時鐘頻率，1分鐘一次

Intent.ACTION_TIME_CHANGED 時鐘改變，使用者在設定中修改了設定時間選項

Intent.ACTION_TIMEZONE_CHANGED 時區改變，使用者在設定中修改了選擇時區

Intent.ACTION_CONFIGURATION_CHANGED 系統配置改變，如修改系統語言、系統螢幕方向發生改變

Intent.ACTION_USER_SWITCHED 切換使用者，機主或其它訪客之間切換

我們看到系統設定介面中的 使用24小時制 開關，點選後時間會立馬改變顯示，就是通過傳送 ACTION_TIME_CHANGED 廣播，

攜帶 EXTRA_TIME_PREF_24_HOUR_FORMAT 引數 ，下面是核心程式碼

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，發現 EXTRA_TIME_PREF_24_HOUR_FORMAT 並沒有被用上，繼續深究程式碼

 final void updateClock() {
    if (mDemoMode) return;
    mCalendar.setTimeInMillis(System.currentTimeMillis());
    setText(getSmallTime());
    setContentDescription(mContentDescriptionFormat.format(mCalendar.getTime()));
}

收到廣播最終都會呼叫 updateClock()，可以看到真正設定時間是通過 getSmallTime() 這個核心方法

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;

}

方法有點長，我們挑主要的分析一下，DateFormat.is24HourFormat() 最終通過讀取 Settings.System.TIME_12_24值，

這個值正好在上面的 TimeFormatPreferenceController 中點選24小時開關是改變，如果這個值為null，則通過獲取本地時間

Local 來獲取當前時間格式，如果等於24則返回true，該方法的原始碼可在AS中點進去檢視，此處就不貼了。

LocaleData 是一個時間格式管理類，在 DateUtils.java 和 SimpleDateFormat.java 中都頻繁使用

接下來獲取到的 format 為 d.timeFormat_Hm， 設定給 SimpleDateFormat(d.timeFormat_Hm)

String result = sdf.format(mCalendar.getTime());就是當前需要顯示的時間，此處還需要做一下格式化

mAmPmStyle 是通過建構函式自定義屬性賦值的，xml中並沒有賦值，取預設值 AM_PM_STYLE_GONE，走這段程式碼

formatted.delete(magic1, magic2+1); 去除多餘的 '\uEF00' 和 '\uEF01'，最終顯示的就是 formatted。

參考文章

https://blog.csdn.net/weilaideta/article/details/51760434

https://blog.csdn.net/W1107101310/article/details/80211