在外部控制器val更改后更新过滤器结果

Question

我有一项控制用户常规设置的服务。

其中一个设置是日期的全球时间格式。 例如 - 如果用户选择了美国格式，则呈现给用户的所有时间都应采用AM PM格式，否则将呈现24小时时间。

*  *设置全局用户设置  * /

app.factory('UserSettings', ['localStorageService', function (localStorageService) {

    var UserSettings = {};

    /**
     * The user settings
     * @type {}
     */
    var userSettings = null;

    /**
     * The user settings key for the local storage
     * @type {string}
     */
    var userSettingsKey = 'userSettings';

    /**
     * Get the user settings
     * Timeformat - 1 = international
     * Timeformat - 2 = U.S
     * @return {Object}
     */
    UserSettings.getUserSettings = function () {
        if (!userSettings) {
            userSettings = localStorageService.get(userSettingsKey);
            if (!userSettings)
            //Default user settings
                userSettings = {timeFormat: 1}
        }
        return userSettings;
    };

    /**
     * Set the user settings object in the scope and in the local storage
     * @param {Object}
     */
    UserSettings.setUserSettings = function (settings) {
        if (settings) {
            var success = localStorageService.set(userSettingsKey, settings);
            if (success)
                userSettings = settings;
            return success;
        }
    };

    return UserSettings;

}]);

所选格式正在过滤器中激活

  

timeFormatFilter

/**
 * Get a formatted text from timestemp
 * It will return the time in the format that was set inside the UserSettings
 */
app.filter('timeFormatFilter', ['UserSettings', function (UserSettings) {
    var userSettings;
    /**
     * @param time The time
     * @param isDate if to return a string with a date
     * @param isTime if to return a string with a time
     */
    return function (time, isDate, isTime) {
        var formattedTime = '';

        if (!time)
            return formattedTime;
        userSettings = UserSettings.getUserSettings();

        var utcTime = moment(time).utc();

        if (isDate)
            formattedTime = formattedTime + getDate(utcTime) + ' ';
        if (isTime)
            formattedTime = formattedTime + getTime(utcTime);

        return formattedTime;
    };

    /**
     * Get a date string in the format that is set inside the UserSettings
     * @param utcTime
     * @returns {string}
     */
    function getDate(utcTime) {
        var date = '';

        switch (userSettings.timeFormat) {
            case 1:
                date = utcTime.format('DD/MM/YYYY');
                break;
            case 2:
                date = utcTime.format('MM/DD/YYYY');
                break;
        }
        return date;

    }

    /**
     * Get a time string in the format that is set inside the UserSettings
     * @param utcTime
     * @returns {string}
     */
    function getTime(utcTime) {
        var time = '';
        switch (userSettings.timeFormat) {
            case 1:
                time = utcTime.format('HH:mm');
                break;
            case 2:
                time = utcTime.format('h:mm a');
                break;
        }
        return time;
    }
}]);

HTML：

 {{startTime| timeFormatFilter:true:false}}

此过程正常，但在更改UserSettings后不会调用过滤器。我想以某种方式将过滤器激活绑定到UserSettings的更改。

我在这里看到了一些问题，但没有人回答我的问题。