Use delegate to pass values between two Viewcontroller

The following implementation of the use of delegate in two viewcontroller between the value, this scenario is generally applied to enter the sub-interface input information, after the completion of the input information back to the previous interface , such as modify the user's personal information, click Modify to enter the modified interface, After the modification, the display screen displays the modified results.

The method declared in the agreement:

1. #import <Foundation/Foundation.h>
2. @class userentity;
4. @protocol passvaluedelegate <NSObject>
6. -(void) Passvalue: (userentity *) value;
8. @end

Implement the Protocol in the first window:

1. #import <UIKit/UIKit.h>
2. #import "PassValueDelegate.h"
4. The first window complies with Passvaluedelegate
5. @interface viewcontroller:uiviewcontroller<passvaluedelegate>
7. @property (Retain, nonatomic) Iboutlet UILabel *namelabel;
8. @property (Retain, nonatomic) Iboutlet UILabel *agelabel;
9. @property (Retain, nonatomic) Iboutlet UILabel *gendarlabel;
11. -(Ibaction) openbtnclicked: (ID) sender;
13. @end

Ways to implement protocols in. m Files:

[CPP]View Plaincopy < param name= "wmode" value= "Transparent" >

1. Implement the Protocol in the first window to display the value entered in the second window, similar to the Onactivityresult method in Android
2. -(void) Passvalue: (userentity *) value
3. {
4. Self.nameLabel.text = Value.username;
5. Self.ageLabel.text = [NSString stringwithformat:@ "%d", value.age];
6. Self.gendarLabel.text = Value.gendar;
7. }

Click on the event triggered by the Open button:

//Click on the method to enter the second window

1. -(Ibaction) openbtnclicked: (ID) Sender {
2. Secondviewcontroller *secondview = [[Secondviewcontroller alloc] initwithnibname:@ "Secondviewcontroller" bundle:[ NSBundle Mainbundle]];
3. Set the delegate in the second window to the self of the first window
4. Secondview.delegate = self;
6. [Self.navigationcontroller Pushviewcontroller:secondview Animated:yes];
7. [Secondview release];
8. }

The second window declares a NSObject object that adheres to the Passvaluedelegate protocol:

1. #import  <uikit/uikit.h>  
2. #import   "PassValueDelegate.h"   
3.   
4. @interface  secondviewcontroller : uiviewcontroller   
5.   
6. @property   (retain, nonatomic)  IBOutlet  uitextfield *nametextfield;  
7. @property   (retain, nonatomic)  iboutlet  uitextfield *agetextfiled;  
8. @property   (retain, nonatomic)   iboutlet uitextfield *gendartextfield;  
9.   
10. // This is done with assign instead of retain to prevent circular references from being generated.   
11. @property (nonatomic,assign)  NSObject<PassValueDelegate> *delegate;   
12.   
13. -  (ibaction) okbtnclicked: (ID) sender;  
14. -  ( ibaction) Closekeyboard: (ID) sender;  
15.   
16. @end   

When you are finished typing, click the OK button to trigger the event:

2. -(Ibaction) okbtnclicked: (ID) Sender {
4. userentity *userentity = [[Userentity alloc] init];
6. Userentity.username = Self.nameTextField.text;
8. Userentity.gendar = Self.gendarTextField.text;
10. Userentity.age = [Self.ageTextFiled.text intvalue];
14. Passing a value through a delegated protocol
16. [Self.delegate passvalue:userentity];
18. Go back to the first window
20. [Self.navigationcontroller Popviewcontrolleranimated:yes];
24. [Userentity release];
26. }

Use delegate to pass values between two Viewcontroller