属性传值 Block传值

Posted 2020-06-15

属性传值 就是将A页面的数据传到B页面上，下面就是将FirstViewController的TextField的内容传递到SecondViewController页面的导航栏标题和控制台输出上

 

 

#import

 

@interface FirstViewController :UIViewController

{

UITextField *tf;

}

@end

 

#import "FirstViewController.h"

#import "SecondViewController.h"//要将数据传到哪一个页面(ViewController)就引用那个头文件

 

- (void)viewDidLoad

{

[superviewDidLoad];

//定义一个按钮

UIButton* button = [UIButtonbuttonWithType:UIButtonTypeRoundedRect];

 

button.frame=CGRectMake(100,100,100,100);

 

button.backgroundColor= [UIColorredColor];

 

[button addTarget:selfaction:@selector(doButton)forControlEvents:UIControlEventTouchUpInside];

 

[self.viewaddSubview:button];

 

tf = [[UITextFieldalloc]initWithFrame:CGRectMake(10,300,100,40)];

tf.tintColor = [UIColororangeColor];

tf.backgroundColor = [UIColorgrayColor];

tf.tag =1000;

[self.viewaddSubview:tf];

}

-(void)doButton{

 

 

tf = (UITextField *)[self.viewviewWithTag:1000];

//push入栈引用计数+1，且控制权归系统

SecondViewController * seV =[[SecondViewControlleralloc]init];//将其实例化，否则找不到相应的属性

//直接属性传值

seV.naviTitle =tf.text;

seV.str [email protected]"传值成功";//属性(赋值)所要传的值要写在推出下一个窗口前面

 

[self.navigationControllerpushViewController:seVanimated:YES];

}

 

@end

 

 

 

#import

 

@interface SecondViewController :UIViewController

@property(nonatomic,strong)NSString * str;

@property (nonatomic,retain)NSString *naviTitle;

@end

 

 

 

#import "SecondViewController.h"

 

@interface SecondViewController ()

 

@end

 

@implementation SecondViewController

@synthesize naviTitle =_naviTitle;

 

- (void)viewDidLoad

{

[superviewDidLoad];

// Do any additional setup after loading the view.

self.view = [[UIViewalloc]initWithFrame:CGRectMake(0,0,320,480)];

self.title =self.naviTitle;//只是为了显示第一页面传过来的内容将其显示到导航标题上

}

 

-(void)viewWillAppear:(BOOL)animated{

 

NSLog(@"%@",self.str);

 

NSLog(@"11---%@",self.naviTitle);

 

}

@end

 

Block传值

 

 

#import

 

@interface FirstViewController :UIViewController

{

UITextField *tf;

}

@property (nonatomic,retain)UILabel *label;

@end

 

#import "FirstViewController.h"

#import "SecondViewController.h"

 

@implementation FirstViewController

- (void)viewDidLoad

{

[superviewDidLoad];

//定义一个按钮

UIButton* button = [UIButtonbuttonWithType:UIButtonTypeRoundedRect];

 

button.frame=CGRectMake(100,100,100,100);

 

button.backgroundColor= [UIColorredColor];

 

[button addTarget:selfaction:@selector(doButton)forControlEvents:UIControlEventTouchUpInside];

 

[self.viewaddSubview:button];

//定义一个显示控件

self.label = [[UILabelalloc]initWithFrame:CGRectMake(0,400, 100, 40)];

 

self.label.backgroundColor = [UIColorgreenColor];

 

self.label.text = nil;//为了显示第二个视图控制器传过来的字符串

 

[self.viewaddSubview:self.label];

 

}

-(void)doButton{

 

tf = (UITextField *)[self.viewviewWithTag:1000];

//push入栈引用计数+1，且控制权归系统

SecondViewController * seV =[[SecondViewControlleralloc]init];//相对应的将其实例化，否则找不到相应的属性

 

//回调方法将输入框中的数据传输过来

[seVreturnText:^(NSString *showText) {

self.label.text = showText;

}];

[self.navigationControllerpushViewController:seV animated:YES];

 

 

}

@end

#import

typedefvoid (^ReturnTextBlock)(NSString *showText);//重新定义了一个名字

@interface SecondViewController :UIViewController

@property (nonatomic,retain)UITextField *tf;

@property (nonatomic,copy) ReturnTextBlock returnTextBlock;//定义的一个Block属性

- (void)returnText:(ReturnTextBlock)block;

@end

#import "SecondViewController.h"

 

 

- (void)viewDidLoad

{

[superviewDidLoad];

//定义一个输入框 将文字传给第一个界面，并且显示在UILabel上

self.tf = [[UITextFieldalloc]initWithFrame:CGRectMake(10,300, 100, 40)];

self.tf.tintColor = [UIColororangeColor];

self.tf.backgroundColor = [UIColorgrayColor];

[self.viewaddSubview:self.tf];

 

}

 

//在第一个界面传进来一个Block语句块的函数

//把传进来的Block语句块保存到本类的实例变量returnTextBlock（.h中定义的属性）中，然后寻找一个时机调用

-(void)returnText:(ReturnTextBlock)block{

self.returnTextBlock = block;

}

//而这个时机就是当视图将要消失的时候，需要重写：

-(void)viewWillDisappear:(BOOL)animated{

if (self.returnTextBlock !=nil) {

self.returnTextBlock(self.tf.text);

NSLog(@"self.tf.text %@",self.tf.text);

}

}

@end