技術標籤：ANDROID

新的專案，手機充電的時候，systemui顯示慢速充電。

通過電流計測量，充電電流為1.7A，電壓5v，這個功率還挺高的，怎麼就提示慢速充電了呢。

檢視程式碼http://aospxref.com/android-11.0.0_r21/xref/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/KeyguardIndicationController.java

    protected String computePowerIndication() {
        if (mPowerCharged) {
            return mContext.getResources().getString(R.string.keyguard_charged);
        }

        final boolean hasChargingTime = mChargingTimeRemaining > 0;
        int chargingId;
        if (mPowerPluggedInWired) {
            switch (mChargingSpeed) {
                case BatteryStatus.CHARGING_FAST:
                    chargingId = hasChargingTime
                            ? R.string.keyguard_indication_charging_time_fast
                            : R.string.keyguard_plugged_in_charging_fast;
                    break;
                case BatteryStatus.CHARGING_SLOWLY:
                    chargingId = hasChargingTime
                            ? R.string.keyguard_indication_charging_time_slowly
                            : R.string.keyguard_plugged_in_charging_slowly;
                    break;
                default:
                    chargingId = hasChargingTime
                            ? R.string.keyguard_indication_charging_time
                            : R.string.keyguard_plugged_in;
                    break;
            }
        } else {
            chargingId = hasChargingTime
                    ? R.string.keyguard_indication_charging_time_wireless
                    : R.string.keyguard_plugged_in_wireless;
        }
 

mChargingSpeed = status.getChargingSpeed(mContext);

http://aospxref.com/android-11.0.0_r21/xref/frameworks/base/packages/SettingsLib/src/com/android/settingslib/fuelgauge/BatteryStatus.java

    public final int getChargingSpeed(Context context) {
        final int slowThreshold = context.getResources().getInteger(
                R.integer.config_chargingSlowlyThreshold);
        final int fastThreshold = context.getResources().getInteger(
                R.integer.config_chargingFastThreshold);
        return maxChargingWattage <= 0 ? CHARGING_UNKNOWN :
                maxChargingWattage < slowThreshold ? CHARGING_SLOWLY :
                        maxChargingWattage > fastThreshold ? CHARGING_FAST :
                                CHARGING_REGULAR;
    }
 

    public BatteryStatus(Intent batteryChangedIntent) {
        status = batteryChangedIntent.getIntExtra(EXTRA_STATUS, BATTERY_STATUS_UNKNOWN);
        plugged = batteryChangedIntent.getIntExtra(EXTRA_PLUGGED, 0);
        level = batteryChangedIntent.getIntExtra(EXTRA_LEVEL, 0);
        health = batteryChangedIntent.getIntExtra(EXTRA_HEALTH, BATTERY_HEALTH_UNKNOWN);

        final int maxChargingMicroAmp = batteryChangedIntent.getIntExtra(EXTRA_MAX_CHARGING_CURRENT,
                -1);
        int maxChargingMicroVolt = batteryChangedIntent.getIntExtra(EXTRA_MAX_CHARGING_VOLTAGE, -1);

        if (maxChargingMicroVolt <= 0) {
            maxChargingMicroVolt = DEFAULT_CHARGING_VOLTAGE_MICRO_VOLT;
        }
        if (maxChargingMicroAmp > 0) {
            // Calculating muW = muA * muV / (10^6 mu^2 / mu); splitting up the divisor
            // to maintain precision equally on both factors.
            maxChargingWattage = (maxChargingMicroAmp / 1000)
                    * (maxChargingMicroVolt / 1000);
        } else {
            maxChargingWattage = -1;
        }
    }
 

http://aospxref.com/android-11.0.0_r21/xref/frameworks/base/packages/SettingsLib/res/values/config.xml

<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
<!--  Threshold in micro watts below which a charger is rated as "slow"; 1A @ 5V  -->
<integer name="config_chargingSlowlyThreshold">5000000</integer>
<!--  Threshold in micro watts above which a charger is rated as "fast"; 1.5A @ 5V   -->
<integer name="config_chargingFastThreshold">7500000</integer>
</resources>

也就是低於5w顯示慢速充電，高於7.5w顯示快速充電，大於5w而小於7.5w顯示正在充電。

當然分析的是Android原生程式碼，mtk應該對這一塊作了定製，要下週到公司look下原始碼了。