在下面的代码中，我设法checkSchedule每 15 秒触发一次我的方法（用于测试目的），checkSchedule将发送一个 API，然后检查是否有任何约会。如果 检测到结果connectionFinishLoading，它会通知用户。
如果应用程序位于前台或后台，则当前代码将起作用。
但是，我希望在应用程序被终止或手机重新启动并且应用程序未启动时让它工作。基本上，该功能类似于Any.do应用程序（A提醒应用程序），即使在应用程序被杀死或手机重启时也会触发提醒。任何指示或帮助将不胜感激。
@AppDelegate.m
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
[self startTimerLoop];
return YES;
}
//==== This loop will run every hour and call Check Schedule,
//==== It will break the 3 min barrier
-(void)startTimerLoop{
//NSLog(@"Hi I am in the timer .. %@ ", [NSDate date]);
[objTimer invalidate];
objTimer = nil;
//===repeat every 15 secs for testing purposes
bgTask = UIBackgroundTaskInvalid;
UIApplication *app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{}];
objTimer = [NSTimer scheduledTimerWithTimeInterval:15 target:self selector:@selector(checkSchedule) userInfo:nil repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:objTimer forMode:UITrackingRunLoopMode];
}
//=== Check from 2 hours from now if there is any classes
//=== it will send and web API and is it return a result,
//=== it will notify the user
-(void)checkSchedule{
//=== Initialize the responseData Mutable Data
self.responseData = [NSMutableData data];
//=== Call the stored txtMemCode, something like session ---
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString *sMemCode = [defaults objectForKey:@"txtMemCode"];
NSDate *now = [NSDate date];
NSDateFormatter *outputFormatter = [[NSDateFormatter alloc] init];
[outputFormatter setDateFormat:@"HH:mm"];
NSString *sTime = [outputFormatter stringFromDate:now];
sTime = [sTime stringByReplacingOccurrencesOfString:@":" withString:@"%3A"];
//====Check from 2 hours from now====
NSTimeInterval secInTwoHours = 2*60*60; //=== sec in 2 hours
NSDate *twoHoursAhead = [now dateByAddingTimeInterval:secInTwoHours];
NSString *sTime2Hours = [outputFormatter stringFromDate:twoHoursAhead];
sTime2Hours = [sTime2Hours stringByReplacingOccurrencesOfString:@":" withString:@"%3A"];
if (sMemCode != nil) {
//=== Pass the string to web and get the return State response.write
sURL = gURL;
sURL = [sURL stringByAppendingString:@"/apps/checkBooking.asp?"];
sURL = [sURL stringByAppendingString:@"memCode="];
sURL = [sURL stringByAppendingString:sMemCode];
sURL = [sURL stringByAppendingString:@"&tocheck="];
sURL = [sURL stringByAppendingString:sTime];
sURL = [sURL stringByAppendingString:@"&tocheck2="];
sURL = [sURL stringByAppendingString:sTime2Hours];
NSLog(@" The sURL : %@ ", sURL);
NSURLRequest *requestState = [NSURLRequest requestWithURL:[NSURL URLWithString:sURL]];
(void) [[NSURLConnection alloc] initWithRequest:requestState delegate:self];
}
}
//=== This getting the return results from the called API.
//=== If there is a result, it will notify the user.
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
NSLog(@"connectionDidFinishLoading");
NSLog(@"=========Succeeded! Received %d bytes of data",[self.responseData length]);
NSString *sResponseData = [[NSString alloc] initWithData:self.responseData encoding:NSUTF8StringEncoding];
NSLog(@"=======*************** This Response.write stuff %@", sResponseData);
NSString *sSeparator= @"|";
NSRange range = [sResponseData rangeOfString:sSeparator];
NSInteger position = range.location + range.length;
NSString *sRecords = [sResponseData substringToIndex:position-1];
NSString *sRemaining = [sResponseData substringFromIndex:position];
if ([sRecords isEqualToString:@"0"]){
NSLog(@" There is no classes ");
}else {
range = [sRemaining rangeOfString:sSeparator];
position = range.location + range.length;
NSString *sMessage = [sRemaining substringToIndex:position-1];
NSString *sTime = [sRemaining substringFromIndex:position];
NSString *sBody = sMessage;
sBody = [sBody stringByAppendingString:@" "];
sBody = [sBody stringByAppendingString:sTime];
UNMutableNotificationContent* content = [[UNMutableNotificationContent alloc] init];
content.title = [NSString localizedUserNotificationStringForKey:@"Class Reminder!"
arguments:nil];
content.body = [NSString localizedUserNotificationStringForKey:sBody
arguments:nil];
content.sound = [UNNotificationSound defaultSound];
UNTimeIntervalNotificationTrigger *trigger = [UNTimeIntervalNotificationTrigger triggerWithTimeInterval:1 repeats:NO];
UNNotificationRequest *notificationRequest = [UNNotificationRequest requestWithIdentifier:@"NotificationIdentifier" content:content trigger:trigger];
UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];
[center addNotificationRequest:notificationRequest
withCompletionHandler:^(NSError * _Nullable error) {
NSLog(@"completed!");
}];
}
[[UIApplication sharedApplication] endIgnoringInteractionEvents];
}