在iPhone中创建基于时间的提醒应用程序

Question

我正在研究基于时间的提醒应用程序.其中用户输入他的提醒和提醒时间.问题是如何连续比较当前时间和用户定义的时间.任何示例代码都会有很大帮助.因为我坚持这一点.

Answer 1

比较当前时间与用户定义的时间不是正确的设计模式.

UIKit提供了NSLocalNotification对象,它是您的任务的更高级抽象.

下面是一段代码,用于在选择的时间创建和安排本地通知:

    UILocalNotification *aNotification = [[UILocalNotification alloc] init];
    aNotification.fireDate = [NSDate date];
    aNotification.timeZone = [NSTimeZone defaultTimeZone];

    aNotification.alertBody = @"Notification triggered";
    aNotification.alertAction = @"Details";

    /* if you wish to pass additional parameters and arguments, you can fill an info dictionary and set it as userInfo property */
    //NSDictionary *infoDict = //fill it with a reference to an istance of NSDictionary;
    //aNotification.userInfo = infoDict;

    [[UIApplication sharedApplication] scheduleLocalNotification:aNotification];
    [aNotification release];

此外,请务必设置AppDelegate以响应本地通知,无论是在启动时还是在应用程序的正常运行时期间(如果您希望在应用程序处于前台时收到通知):

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

    UILocalNotification *aNotification = [launchOptions objectForKey: UIApplicationLaunchOptionsLocalNotificationKey]; 

    if (aNotification) {
        //if we're here, than we have a local notification. Add the code to display it to the user
    }


    //...
    //your applicationDidFinishLaunchingWithOptions code goes here
    //...


        [self.window makeKeyAndVisible];
    return YES;
}



- (void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification {

        //if we're here, than we have a local notification. Add the code to display it to the user


}

有关Apple Developer Documentation的更多详细信息.