App Standby黑白名單配置流程

如圖所示，可選擇優化和不優化

程式碼路徑：packages\apps\Settings\src\com\android\settings\fuelgauge\HightPowerDetail

    @Override
    public void onClick(DialogInterface dialog, int which) {
        if (which == DialogInterface.BUTTON_POSITIVE) {
            boolean newValue = mIsEnabled;
            boolean oldValue = mBackend.isWhitelisted(mPackageName);
            if (newValue != oldValue) {
                logSpecialPermissionChange(newValue, mPackageName, getContext());
                if (newValue) {
                    mBackend.addApp(mPackageName);
                } else {
                    mBackend.removeApp(mPackageName);
                }
            }
        }
    }
 

繼續跟蹤mBackend

packages\apps\Settings\src\com\android\settings\fuelgauge\PowerWhitelistBackend

    public void addApp(String pkg) {
        try {
            mDeviceIdleService.addPowerSaveWhitelistApp(pkg);
            mWhitelistedApps.add(pkg);
        } catch (RemoteException e) {
            Log.w(TAG, "Unable to reach IDeviceIdleController", e);
        }
    }
 

DeviceIdleController.java-->addPowerSaveWhitelistApp()

        @Override public void addPowerSaveWhitelistApp(String name) {
            if (DEBUG) {
                Slog.i(TAG, "addPowerSaveWhitelistApp(name = " + name + ")");
            }
            getContext().enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER,
                    null);
            long ident = Binder.clearCallingIdentity();
            try {
                addPowerSaveWhitelistAppInternal(name);
            } finally {
                Binder.restoreCallingIdentity(ident);
            }
        }
 

DeviceIdleController.java-->addPowerSaveWhitelistAppInternal()

    public boolean addPowerSaveWhitelistAppInternal(String name) {
        synchronized (this) {
            try {
                ApplicationInfo ai = getContext().getPackageManager().getApplicationInfo(name,
                        PackageManager.MATCH_ANY_USER);
                if (mPowerSaveWhitelistUserApps.put(name, UserHandle.getAppId(ai.uid)) == null) {
                    reportPowerSaveWhitelistChangedLocked();
                    updateWhitelistAppIdsLocked();
                    //將該集合遍歷出來寫入檔案
                    writeConfigFileLocked();
                }
                return true;
            } catch (PackageManager.NameNotFoundException e) {
                return false;
            }
        }
    }

通過應用名獲取到對應的ApplicationInfo,然後將應用名存入mPowerSaveWhitelistUserApps集合裡，再呼叫writeConfigFileLocked將該集合遍歷出來寫入檔案。 

    void writeConfigFileLocked() {
        mHandler.removeMessages(MSG_WRITE_CONFIG);
        mHandler.sendEmptyMessageDelayed(MSG_WRITE_CONFIG, 5000);
    }

                case MSG_WRITE_CONFIG: {
                    // Does not hold a wakelock. Just let this happen whenever.
                    handleWriteConfigFile();
                } break;

    void handleWriteConfigFile() {
        final ByteArrayOutputStream memStream = new ByteArrayOutputStream();

        try {
            synchronized (this) {
                XmlSerializer out = new FastXmlSerializer();
                out.setOutput(memStream, StandardCharsets.UTF_8.name());
                writeConfigFileLocked(out);
            }
        } catch (IOException e) {
        }

        synchronized (mConfigFile) {
            FileOutputStream stream = null;
            try {
                stream = mConfigFile.startWrite();
                memStream.writeTo(stream);
                stream.flush();
                FileUtils.sync(stream);
                stream.close();
                mConfigFile.finishWrite(stream);
            } catch (IOException e) {
                Slog.w(TAG, "Error writing config file", e);
                mConfigFile.failWrite(stream);
            }
        }
    }

我們看下這個mConfigFile = new AtomicFile(new File(getSystemDir(), "deviceidle.xml"));

<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<config>
<wl n="com.tencent.mm" />
<wl n="com.sina.weibo" />
<wl n="com.tencent.mobileqq" />
<wl n="com.skype.raider" />
<wl n="com.skype.m2" />
<wl n="com.bbm" />
<wl n="com.facebook.katana" />
<wl n="com.whatsapp" />
<wl n="jp.naver.line.android" />
<wl n="com.twitter.android" />
<wl n="com.instagram.android" />
<wl n="com.facebook.orca" />
<wl n="com.facebook.mlite" />
<wl n="com.viber.voip" />
<wl n="com.imo.android.imoim" />
<wl n="com.imo.android.imoimbeta" />
<wl n="pro.imoc.allvideo" />
<wl n="com.facebook.pages.app" />
<wl n="com.facebook.Mentions" />
</config>