iOS four ways to reverse-pass values

Method One: Use target-action design mode

The code is as follows: (the child view is rolled out by the root view, then the root view is rolled up, and when the root view is rolled out, the child view passes a color attribute to the root view to modify the background color of the root view)

Root View Controller code:

. m file-  (void) viewdidload{    [super viewdidload];         self.view.backgroundColor = [UIColor redColor];         [self createbutton];} -  (void) createbutton{    uibutton * btn = [uibutton  buttonwithtype:uibuttontypecustom];        btn.frame =  CGRectMake (10, 30, 300, 40);     [btn settitle:@ "Go to Next View controller"   forstate:uicontrolstatenormal];    btn.layer.cornerradius = 5;         btn.backgroundColor = [UIColor blackColor];         [btn addtarget:self action: @selector (btnclick)  forcontrolevents: Uicontroleventtouchupinside];        [self.view addsubVIEW:BTN];} -  (void) btnclick{    sub1viewcontroller * sub1 = [[ Sub1viewcontroller alloc]init];        sub1.view.backgroundcolor  = [UIColor blueColor];        sub1.target =  self;        sub1.action =  @selector (changeColor:);         [self presentViewController:sub1 animated:YES  Completion:nil];} -  (void) ChangeColor: (uicolor *) color{    self.view.backgroundcolor =  Color;}

Child View Code:

. h file @interface sub1viewcontroller : uiviewcontroller@property  (Assign,readwrite, nonatomic) id target; @property   (assign,readwrite,nonatomic) sel action; @end//.m file-  (void) viewdidload{    [super viewdidload];        [ SELF CREATEPOPTOROOTVIEWBTN];} -  (void) Createpoptorootviewbtn{    uibutton * btn = [uibutton  buttonwithtype:uibuttontypecustom];        btn.frame =  cgrectmake (10, 30, 300, 40);     [btn settitle:@ "Go to Root View Controller"   forstate:uicontrolstatenormal];    btn.layer.cornerradius = 5;         btn.backgroundColor = [UIColor blackColor];         [btn addtarget:self action: @selector (Btnclick)  forcontrolevents:uICONTROLEVENTTOUCHUPINSIDE];        [SELF.VIEW ADDSUBVIEW:BTN];} -  (void) btnclick{    if  ([_target respondstoselector:_action])      {        [_target performSelector:_action  withobject:[uicolor orangecolor]];    }    [self  Dismissviewcontrolleranimated:yes completion:nil];}

Method Two: Notifications

. m root View-  (void) viewdidload{    [super viewdidload];         self.view.backgroundColor = [UIColor redColor];         [self createbutton];        [[ Nsnotificationcenter defaultcenter] addobserver:self selector: @selector (changeColor:)  name : @ "ChangeColor"  object:nil];} -  (void) createbutton{    uibutton * btn = [uibutton  buttonwithtype:uibuttontypecustom];        btn.frame =  CGRectMake (10, 30, 300, 40);     [btn settitle:@ "Go to Next View controller"   forstate:uicontrolstatenormal];    btn.layer.cornerradius = 5;         btn.backgroundColor = [UIColor blackColor];      &nBsp;  [btn addtarget:self action: @selector (btnclick)  forcontrolevents: UICONTROLEVENTTOUCHUPINSIDE];        [SELF.VIEW ADDSUBVIEW:BTN];} -  (void) btnclick{    sub1viewcontroller * sub1 = [[ Sub1viewcontroller alloc]init];        sub1.view.backgroundcolor  = [UIColor blueColor];        [self  Presentviewcontroller:sub1 animated:yes completion:nil];} -  (void) ChangeColor: (nsnotification *) nofi{    self.view.backgroundcolor =  [nofi.userinfo objectforkey:@ "Color"];}

Child View Code

-  (void) viewdidload{    [super viewdidload];         [SELF CREATEPOPTOROOTVIEWBTN];} -  (void) Createpoptorootviewbtn{    uibutton * btn = [uibutton  buttonwithtype:uibuttontypecustom];        btn.frame =  cgrectmake (10, 30, 300, 40);     [btn settitle:@ "Go to Root View Controller"   forstate:uicontrolstatenormal];    btn.layer.cornerradius = 5;         btn.backgroundColor = [UIColor blackColor];         [[nsnotificationcenter defaultcenter]postnotificationname:@ "ChangeColor"  object:self userinfo:[nsdictionary dictionarywithobjectsandkeys:[uicolor orangecolor],@ " Color ",  nil]];        [btn addtarget:selF action: @selector (Btnclick)  forControlEvents:UIControlEventTouchUpInside];         [self.view addsubview:btn];        }-   (void) Btnclick{    [self dismissviewcontrolleranimated:yes completion:nil] ;}

Method Three: code block

Root View Code:

-  (void) viewdidload{    [super viewdidload];         self.view.backgroundColor = [UIColor redColor];         [self createbutton];} -  (void) createbutton{    uibutton * btn = [uibutton  buttonwithtype:uibuttontypecustom];        btn.frame =  CGRectMake (10, 30, 300, 40);     [btn settitle:@ "Go to Next View controller"   forstate:uicontrolstatenormal];    btn.layer.cornerradius = 5;         btn.backgroundColor = [UIColor blackColor];         [btn addtarget:self action: @selector (btnclick)  forcontrolevents: Uicontroleventtouchupinside];        [self.view addsubview:bTN];} -  (void) btnclick{    sub1viewcontroller * sub1 = [[ Sub1viewcontroller alloc]init];        sub1.view.backgroundcolor  = [uicolor bluecolor];        sub1. myblock = ^ (Uicolor * color)     {         self.view.backgroundColor = color;    };         [self presentviewcontroller:sub1 animated:yes completion:nil];}

Child View Code

. h file @interface sub1viewcontroller : uiviewcontroller@property  (copy,nonatomic,readwrite) void  (^myblock) (uicolor * color); @end//.m file-  (void) viewdidload{    [ SUPER VIEWDIDLOAD];        [SELF CREATEPOPTOROOTVIEWBTN];} -  (void) Createpoptorootviewbtn{    uibutton * btn = [uibutton  buttonwithtype:uibuttontypecustom];        btn.frame =  cgrectmake (10, 30, 300, 40);     [btn settitle:@ "Go to Root View Controller"   forstate:uicontrolstatenormal];    btn.layer.cornerradius = 5;         btn.backgroundColor = [UIColor blackColor];         [btn addtarget:self action: @selector (btnclick)  forcontrolevents: UIControlEventTouchUpInside];        [self.view addSubview:btn];         }-  (void) Btnclick{    _myblock ([Uicolor orangecolor]);     [self dismissviewcontrolleranimated:yes completion:nil];}

Method Four: Agent-protocol

Root View Code

.h#import <uikit/uikit.h> #import   "Sub1ViewController.h" @interface  viewcontroller :  UIViewController<Sub1ViewControllerDelete> @end//.m-  (void) viewdidload{     [super viewDidLoad];        self.view.backgroundColor  = [uicolor redcolor];        [self createbutton];} -  (void) createbutton{    uibutton * btn = [uibutton  buttonwithtype:uibuttontypecustom];        btn.frame =  CGRectMake (10, 30, 300, 40);     [btn settitle:@ "Go to Next View controller"   forstate:uicontrolstatenormal];    btn.layer.cornerradius = 5;         btn.backgroundColor = [UIColor blackColor];         [btn adDtarget:self action: @selector (Btnclick)  forControlEvents:UIControlEventTouchUpInside];   &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;[SELF.VIEW&NBSP;ADDSUBVIEW:BTN];} -  (void) btnclick{    sub1viewcontroller * sub1 = [[ Sub1viewcontroller alloc]init];        sub1.view.backgroundcolor  = [UIColor blueColor];    sub1.delegate = self;     [self presentviewcontroller:sub1 animated:yes completion:nil];} -  (void) ChangeColor: (uicolor *) color{    self.view.backgroundcolor =  Color;}

Child View Controller

. h file #import <uikit/uikit.h> @protocol  Sub1ViewControllerDelete <NSObject>-  ( void) ChangeColor: (uicolor *) color; @end @interface sub1viewcontroller :  uiviewcontroller@property  (Assign,nonatomic,readwrite) id <sub1viewcontrollerdelete>delegate;@ END//.M file-  (void) viewdidload{    [super viewdidload];     &NBSP;&NBSP;&NBSP;&NBSP;[SELF&NBSP;CREATEPOPTOROOTVIEWBTN];} -  (void) Createpoptorootviewbtn{    uibutton * btn = [uibutton  buttonwithtype:uibuttontypecustom];        btn.frame =  cgrectmake (10, 30, 300, 40);     [btn settitle:@ "Go to Root View Controller"   forstate:uicontrolstatenormal];    btn.layer.cornerradius = 5;         btn.backgroundcolor = [uicolor blackcolor]; &Nbsp;      [btn addtarget:self action: @selector (BtnClick)   forcontrolevents:uicontroleventtouchupinside];        [self.view  addsubview:btn];        }-  (void) btnclick{     [_delegate changeColor:[UIColor orangeColor]];         [Self dismissviewcontrolleranimated:yes completion:nil];}

This article is from the Web Learning Summary blog, so be sure to keep this source http://8947509.blog.51cto.com/8937509/1586745

iOS four ways to reverse-pass values