IOS: Reverse-pass data method one when switching views: notification

Notification Method:

1 A (single) notification Center, responsible for managing all notifications in iOS

2. Need to get some kind of notification, must register as observer (SUBSCRIBE)

3. If you no longer need to take some kind of notice, you need to cancel registration.

4. You can send a notification to the notification center that the notification center is forwarded to the appropriate observer (subscriber).

After the first controller and the second controller are joined in a modal manner, each controller is associated with its own class, and the Idetifier identity of the segue is set to a name, and when the data is being transmitted, it needs to be uniquely identified according to the Segue identifier. The method of notification is used when transmitting data in reverse.

1. All Documents:

2. The first controller Firstviewcontroller associated classes are:

3, the second controller Secondviewcontroller the associated class is:

4, to Segue identifier set a name, as the identity

The specific code is as follows:

The Viewcontroller (. h/.m) class associated with the Firstviewcontroller controller:

1 #import "ViewController.h"2 #import "SecondViewController.h"3 4 @interfaceViewcontroller ()5@property (Weak, nonatomic) Iboutlet Uitextfield *Firsttextfield;6 7 @end8 9 @implementationViewcontrollerTen  One- (void) Viewdidload { A [Super Viewdidload]; - } -  the //Override this method, when the view switches, automatically call --(void) Prepareforsegue: (Uistoryboardsegue *) Segue Sender: (ID) Sender - { -     if([Segue.identifier isequaltostring:@"modal"]) +     { -         //Get Destination Controller +Secondviewcontroller *SECONDVC =Segue.destinationviewcontroller; A          at         //forward-passing data -Secondvc.information =Self.firstTextField.text; -          -         //register notice to become an observer -[[Nsnotificationcenter defaultcenter]addobserver:self selector: @selector (receiveinfo:) name:notificationtepyObject: nil]; -     } in } -  to //Receiveinfo Events +-(void) Receiveinfo: (nsnotification*) Notification - { the     //reverse receiving data from a notification *Self.firstTextField.text =[Notification.userinfo Objectforkey:notificationinfokey]; $     Panax Notoginseng     //Cancel Registration -[[Nsnotificationcenter defaultcenter]removeobserver:self Name:notificationtepyObject: nil]; the } + @end

The Secondviewcontroller (. h/.m) class associated with the Secondviewcontroller controller:

1 #import "SecondViewController.h"2 3 @interfaceSecondviewcontroller ()4@property (Weak, nonatomic) Iboutlet Uitextfield *Secondtextfield;5 6 @end7 8 @implementationSecondviewcontroller9 //trigger event on returnTen-(Ibaction) returnclicked: (Uibarbuttonitem *) Sender One { A     //passing data in reverse -      -     //1. Message content theNsdictionary *dicinfo =@{notificationinfokey:self.secondtextfield.text}; -      -     //2, through the Notification center to pass out -[[Nsnotificationcenter Defaultcenter] Postnotificationname:notificationtepyObject: Self userinfo:dicinfo]; +      -     //Close modal window + [Self.presentingviewcontroller dismissviewcontrolleranimated:yes completion:nil]; A     //[self dismissviewcontrolleranimated:yes completion:nil]; at } -  -- (void) Viewdidload { - [Super Viewdidload]; -      -     //Display the text box contents (accept the data passed over) inSelf.secondTextField.text =self.information; - } to  + @end

IOS: Reverse-pass data method one when switching views: notification