IOS Proxy reverse-pass value

In the previous blog iOS Agent protocol, focusing on the concept of principal-agent protocol, this article will focus on their application in the development.

If we have a demand as follows: interface A has a button, a label. From interface a jump to interface B, enter the string in the input box of interface B and display it on the label of interface A. This is a typical example of a reverse value. The core of this example is: "Enter the string in the input box of interface B and display it on the label on interface A." That is: "Interface B Delegate interface a display string, page A is the agent of interface B." The delegate direction agent reverses the value.

So how do we use the proxy design pattern to implement this requirement?

In the program:

1. The tasks to be commissioned are:

1.1 Defining protocols and methods

1.2 Declaring a delegate variable

1.3 Setting up Proxies

1.4 Calling a delegate method from a delegate variable

2. The work that the agent needs to do is:

2.1 Following the agreement

2.2 Implementing a Delegate method

In the BViewController.h:

// defining protocols and methods @protocol Deliverdetegate <nsobject>-(void) SetValue: (NSString *)string; @end @interface Bviewcontroller:uiviewcontroller // declaring a delegate variable ID<DeliverDetegate>b_delegate; @end

In the BVIEWCONTROLLER.M:

@interface Bviewcontroller () <UITextFieldDelegate>*delivertext; @end

-(Ibaction) Deliveraction: (ID) Sender {//invoking a delegate method from a delegate variable//Input Displays the input string and does not enter "not filled in"    if(! [_delivertext.text isequaltostring:@""]) {NSLog (@"b send data to a%@", _delivertext.text); //determine if the methods in the agent are implemented to prevent programs that are not implemented by the agent from crashing        if([Self. B_delegate respondstoselector: @selector (setValue:)]) {[Self.        B_delegate Setvalue:_delivertext.text]; }    }    Else{NSLog (@"b send data to a%@",@"not filled"); //determine if the methods in the agent are implemented to prevent programs that are not implemented by the agent from crashing        if([Self. B_delegate respondstoselector: @selector (setValue:)]) {[Self. B_delegate SetValue:@"not filled"]; }} [Self.navigationcontroller Popviewcontrolleranimated:yes];}

In the AVIEWCONTROLLER.M

#import " AViewController.h " #import " BViewController.h " @interface Aviewcontroller () <DeliverDetegate>*Textlabel; @end

-(Ibaction) Receiveaction: (ID) sender {        // Follow protocol    BVIEWCONTROLLER*BVC = [[Bviewcontroller alloc]init];     = self ;    [Self.navigationcontroller PUSHVIEWCONTROLLER:BVC animated:yes];}

// implement the Delegate method, the SetValue method that is implemented -(void) SetValue: (NSString *)string{    NSLog (@ "  A receives the B data%@",string);     string ;}

The last of the following:

Output log:

As this article is using Xib, omitted some UI details, attached to the code of this article link: source.

Where to write bad, hope to comment on the guidance. thanked ~

IOS Proxy reverse-pass value