IOS enables two-way transfer of data between two controllers _ios

This article for everyone to share the iOS controller data two-way transmission, for your reference, the specific content as follows

First, there are two controllers, controller A, controller B, respectively.
a->b: The data is transmitted by controller A to controller B, which is called the data cis, and the data is transmitted by Controller B to controller A, which is called the reverse transmission.
Shun Chuan: generally by creating a target controller object, the data assigned to the object's members to complete;
inverse: typically used by proxies, where controller A is the agent for Controller B (Controller A listens to Controller B, controller B notifies controller a).
Here is the blogger wrote a simple implementation of two control between the two-way transmission of data between the app demo:
1, this is the interface design:

FirstViewController.h

#import <UIKit/UIKit.h>

@interface firstviewcontroller:uiviewcontroller

@end

Firstviewcontroller.m

#import "FirstViewController.h" #import "SecondViewController.h" @interface Firstviewcontroller () < Secondviewcontrollerdelegate>/** is used to write data, and finally the data is passed to the second interface/@property (weak, nonatomic) Iboutlet Uitextfield *
First2second;

/** is used to display the data that is passed when the second interface returns * * * @property (weak, nonatomic) Iboutlet Uitextfield *displaywithsecond;

@end @implementation Firstviewcontroller-(void) viewdidload {[Super viewdidload]; This method is automatically called when #pragma mark-navigation//Click the Pass button-(void) Prepareforsegue: (Uistoryboardsegue *) Segue Sender: (ID) Sender {S
  Econdviewcontroller *VC = (Secondviewcontroller *) Segue.destinationviewcontroller;
  if (Self.first2Second.text.length > 0) {//Pass the data in the interface to the second interface vc.name = Self.first2Second.text;
//Set Agent vc.delegate = Self for the current controller as the Secondviewcontroller controller; #pragma mark-Implements the Protocol method in Secondviewcontrollerdelegate-(void) Secondviewcontrollerdiddit: (Secondviewcontroller *) Viewcontroller andname: (NSString *) name {//return the data in the second interface to the first interface (this interface) Self.displaywithsecoNd.text = name;

 } @end

SecondViewController.h

#import <UIKit/UIKit.h>
@class secondviewcontroller;

@protocol secondviewcontrollerdelegate <NSObject>

/** secondviewcontrollerdelegate protocol method
-(void) Secondviewcontrollerdiddit: (Secondviewcontroller *) Viewcontroller andname: (NSString *) name;

@end

@interface secondviewcontroller:uiviewcontroller

@property (nonatomic,strong) nsstring *name;
@property (Nonatomic,weak) id<secondviewcontrollerdelegate> delegate;

@end

Secondviewcontroller.m

 #import "SecondViewController.h" @interface Secondviewcontroller ()/** is used to write data, and finally returns the data to
The first interface */@property (weak, nonatomic) Iboutlet Uitextfield *second2first;
/** is used to display the data from the first interface * * * @property (weak, nonatomic) Iboutlet Uitextfield *displaywithfirst;

/** Click this button, the second controller will pop the stack, the interface will return to the first interface * * * (ibaction) Second2first: (UIButton *) sender;

  @end @implementation Secondviewcontroller-(void) viewdidload {[Super viewdidload];

Displays the data information passed over the first interface self.displayWithFirst.text = Self.name; //Click the button, the data will be returned to the first interface display-(ibaction) Second2first: (UIButton *) Sender {if (Self.second2First.text.length > 0) {/ /If there is a controller that implements the Protocol method, the data is passed to the controller if ([Self.delegate respondstoselector: @selector (secondviewcontrollerdiddit:andname:)])
    {[Self.delegate secondviewcontrollerdiddit:self andName:self.second2First.text];
} [Self.navigationcontroller Popviewcontrolleranimated:yes]; } @end 

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