Accounts&Sync(Auto sync should be unchecked by default)追踪

Accounts&Sync(Auto sync should be unchecked by default)追踪
首先在设置中需要添加一个google账号：
账号：sprocommandroid@gmail.com
密码：sprocomm1

点击该账号进入账号设置界面对应的类为：
ManageAccountsSettings.java (android-k\packages\apps\settings\src\com\android\settings\accounts)
该类继承自AccountPreferenceBase.java其中onResume（）方法
    @Override
    public void onResume() {
        super.onResume();
        mStatusChangeListenerHandle = ContentResolver.addStatusChangeListener(
                ContentResolver.SYNC_OBSERVER_TYPE_ACTIVE
                | ContentResolver.SYNC_OBSERVER_TYPE_STATUS
                | ContentResolver.SYNC_OBSERVER_TYPE_SETTINGS,
                mSyncStatusObserver);
        onSyncStateUpdated();
    }
调用了onSyncStateUpdated();用来进行页面的显示，当然也包括默认值的设置，该方法如下

    @Override
    protected void onSyncStateUpdated() {
        // Catch any delayed delivery of update messages
        if (getActivity() == null) return;

        // iterate over all the preferences, setting the state properly for each
        SyncInfo currentSync = ContentResolver.getCurrentSync();

        boolean anySyncFailed = false; // true if sync on any account failed
        Date date = new Date();

        // only track userfacing sync adapters when deciding if account is synced or not
        final SyncAdapterType[] syncAdapters = ContentResolver.getSyncAdapterTypes();
        HashSet<String> userFacing = new HashSet<String>();
        for (int k = 0, n = syncAdapters.length; k < n; k++) {
            final SyncAdapterType sa = syncAdapters[k];
            if (sa.isUserVisible()) {
                userFacing.add(sa.authority);
            }
        }
        for (int i = 0, count = getPreferenceScreen().getPreferenceCount(); i < count; i++) {
            Preference pref = getPreferenceScreen().getPreference(i);
            if (! (pref instanceof AccountPreference)) {
                continue;
            }

            AccountPreference accountPref = (AccountPreference) pref;
            Account account = accountPref.getAccount();
            int syncCount = 0;
            long lastSuccessTime = 0;
            boolean syncIsFailing = false;
            final ArrayList<String> authorities = accountPref.getAuthorities();
            boolean syncingNow = false;
            if (authorities != null) {
                for (String authority : authorities) {
                    SyncStatusInfo status = ContentResolver.getSyncStatus(account, authority);
                    boolean syncEnabled = ContentResolver.getSyncAutomatically(account, authority)
                            && ContentResolver.getMasterSyncAutomatically()//设置自动同步的地方
                            && (ContentResolver.getIsSyncable(account, authority) > 0);
                    boolean authorityIsPending = ContentResolver.isSyncPending(account, authority);
                    boolean activelySyncing = currentSync != null
                            && currentSync.authority.equals(authority)
                            && new Account(currentSync.account.name, currentSync.account.type)
                                    .equals(account);
                    boolean lastSyncFailed = status != null
                            && syncEnabled
                            && status.lastFailureTime != 0
                            && status.getLastFailureMesgAsInt(0)
                               != ContentResolver.SYNC_ERROR_SYNC_ALREADY_IN_PROGRESS;
                    if (lastSyncFailed && !activelySyncing && !authorityIsPending) {
                        syncIsFailing = true;
                        anySyncFailed = true;
                    }
                    syncingNow |= activelySyncing;
                    if (status != null && lastSuccessTime < status.lastSuccessTime) {
                        lastSuccessTime = status.lastSuccessTime;
                    }
                    syncCount += syncEnabled && userFacing.contains(authority) ? 1 : 0;
                }
            } else {
                if (Log.isLoggable(TAG, Log.VERBOSE)) {
                    Log.v(TAG, "no syncadapters found for " + account);
                }
            }
            if (syncIsFailing) {
                accountPref.setSyncStatus(AccountPreference.SYNC_ERROR, true);
            } else if (syncCount == 0) {
                accountPref.setSyncStatus(AccountPreference.SYNC_DISABLED, true);
            } else if (syncCount > 0) {
                if (syncingNow) {
                    accountPref.setSyncStatus(AccountPreference.SYNC_IN_PROGRESS, true);
                } else {
                    accountPref.setSyncStatus(AccountPreference.SYNC_ENABLED, true);
                    if (lastSuccessTime > 0) {
                        accountPref.setSyncStatus(AccountPreference.SYNC_ENABLED, false);
                        date.setTime(lastSuccessTime);
                        final String timeString = formatSyncDate(date);
                        accountPref.setSummary(getResources().getString(
                                R.string.last_synced, timeString));
                    }
                }
            } else {
                accountPref.setSyncStatus(AccountPreference.SYNC_DISABLED, true);
            }
        }

        mErrorInfoView.setVisibility(anySyncFailed ? View.VISIBLE : View.GONE);
    }

追踪过程中查看的几个类：

ManageAccountsSettings.java//账户设置界面

AccountSyncSettings.java//点击同步Header进入具体同步设置界面 

SyncStorageEngine.java (frameworks\base\services\java\com\android\server\content)//用来对同步默认值的设置类

config_syncstorageengine_masterSyncAutomatically//具体值的boolean字串