Android 设置系统时区的源码追踪

    @Override
    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
        final Context themedContext = getPreferenceManager().getContext();
        final PreferenceScreen screen = getPreferenceManager().createPreferenceScreen(
                themedContext);
        screen.setTitle(R.string.system_set_time_zone);
        setPreferenceScreen(screen);
 
        final List<Map<String, Object>> zoneList = ZoneGetter.getZonesList(getActivity());
        final List<ZonePreference> zonePrefs = new ArrayList<>(zoneList.size());
        for (final Map<String, Object> zone : zoneList) {
            zonePrefs.add(new ZonePreference(themedContext, zone));
        }
        zonePrefs.sort(new ZonePrefComparator());
        for (final Preference zonePref : zonePrefs) {
            screen.addPreference(zonePref);
        }
    }

    @Override
    public boolean onPreferenceTreeClick(Preference preference) {
        if (preference instanceof ZonePreference) {
            // Update the system timezone value
            final TimeZoneDetector timeZoneDetector =
                    getActivity().getSystemService(TimeZoneDetector.class);
            ManualTimeZoneSuggestion suggestion = TimeZoneDetector.createManualTimeZoneSuggestion(
                    preference.getKey(), "Settings: Set time zone");
            timeZoneDetector.suggestManualTimeZone(suggestion);
            if (getParentFragment() instanceof TwoPanelSettingsFragment) {
                ((TwoPanelSettingsFragment) getParentFragment()).navigateBack();
            } else if (!getFragmentManager().popBackStackImmediate()) {
                getActivity().finish();
            }
        }
        return super.onPreferenceTreeClick(preference);
    }

    @RequiresPermission(android.Manifest.permission.SUGGEST_MANUAL_TIME_AND_ZONE)
    void suggestManualTimeZone(@NonNull ManualTimeZoneSuggestion timeZoneSuggestion);

   private final ITimeZoneDetectorService mITimeZoneDetectorService;
 
 @Override
    public void suggestManualTimeZone(@NonNull ManualTimeZoneSuggestion timeZoneSuggestion) {
        if (DEBUG) {
            Log.d(TAG, "suggestManualTimeZone called: " + timeZoneSuggestion);
        }
        try {
            mITimeZoneDetectorService.suggestManualTimeZone(timeZoneSuggestion);
        } catch (RemoteException e) {
            throw e.rethrowFromSystemServer();
        }
    }

interface ITimeZoneDetectorService {
  void suggestManualTimeZone(in ManualTimeZoneSuggestion timeZoneSuggestion);
  void suggestTelephonyTimeZone(in TelephonyTimeZoneSuggestion timeZoneSuggestion);
}

  private final TimeZoneDetectorStrategy mTimeZoneDetectorStrategy;
 
  @Override
    public void suggestManualTimeZone(@NonNull ManualTimeZoneSuggestion timeZoneSuggestion) {
        enforceSuggestManualTimeZonePermission();
        Objects.requireNonNull(timeZoneSuggestion);
 
        mHandler.post(() -> mTimeZoneDetectorStrategy.suggestManualTimeZone(timeZoneSuggestion));
    }

void suggestManualTimeZone(@NonNull ManualTimeZoneSuggestion suggestion);

    @Override
    public synchronized void suggestManualTimeZone(@NonNull ManualTimeZoneSuggestion suggestion) {
        Objects.requireNonNull(suggestion);
 
        String timeZoneId = suggestion.getZoneId();
        String cause = "Manual time suggestion received: suggestion=" + suggestion;
        setDeviceTimeZoneIfRequired(ORIGIN_MANUAL, timeZoneId, cause);
    }

    @GuardedBy("this")
    private void setDeviceTimeZoneIfRequired(
            @Origin int origin, @NonNull String newZoneId, @NonNull String cause) {
        Objects.requireNonNull(newZoneId);
        Objects.requireNonNull(cause);
 
        boolean isOriginAutomatic = isOriginAutomatic(origin);
        if (isOriginAutomatic) {
            if (!mCallback.isAutoTimeZoneDetectionEnabled()) {
                if (DBG) {
                    Slog.d(LOG_TAG, "Auto time zone detection is not enabled."
                            + " origin=" + origin
                            + ", newZoneId=" + newZoneId
                            + ", cause=" + cause);
                }
                return;
            }
        } else {
            if (mCallback.isAutoTimeZoneDetectionEnabled()) {
                if (DBG) {
                    Slog.d(LOG_TAG, "Auto time zone detection is enabled."
                            + " origin=" + origin
                            + ", newZoneId=" + newZoneId
                            + ", cause=" + cause);
                }
                return;
            }
        }
 
        String currentZoneId = mCallback.getDeviceTimeZone();
 
        // Avoid unnecessary changes / intents.
        if (newZoneId.equals(currentZoneId)) {
            // No need to set the device time zone - the setting is already what we would be
            // suggesting.
            if (DBG) {
                Slog.d(LOG_TAG, "No need to change the time zone;"
                        + " device is already set to the suggested zone."
                        + " origin=" + origin
                        + ", newZoneId=" + newZoneId
                        + ", cause=" + cause);
            }
            return;
        }
 
        mCallback.setDeviceTimeZone(newZoneId);
        String msg = "Set device time zone."
                + " origin=" + origin
                + ", currentZoneId=" + currentZoneId
                + ", newZoneId=" + newZoneId
                + ", cause=" + cause;
        if (DBG) {
            Slog.d(LOG_TAG, msg);
        }
        mTimeZoneChangesLog.log(msg);
    }

    @Override
    public void setDeviceTimeZone(String zoneId) {
        AlarmManager alarmManager = mContext.getSystemService(AlarmManager.class);
        alarmManager.setTimeZone(zoneId);
    }