iOS-传值大全

朱雀 2022-10-01 00:49 186阅读 0赞

#  #

# 前言 #

[iOS][]传值方式很多，这里面我主要讲几种常用的传值；

以下传值正向传值A页面到B页面，反向传值B页面传到A页面。

# 1.属性传值 #

A页面：

SecondViewController *svc = [[SecondViewController alloc]init];  
    UINavigationController *nvc = [[UINavigationController alloc]initWithRootViewController:svc];  
    svc.passValue = @"这是传的值";  
    [self presentViewController:nvc animated:YES completion:nil];

B页面：

先声明一个属性：

@property (nonatomic,copy) NSString *passValue;

使用传的值

NSLog(@"%@",_passValue);

# 2.文件传值 #

A页面：

NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];  
    [ud setObject:@"这是传的值" forKey:@"passValue"];  
    [ud synchronize];

B页面：

# `NSUserDefaults *ud = [NSUserDefaults standardUserDefaults]; NSString *str = [ud objectForKey:@"passValue"]; NSLog(@"str == %@",str);` #

# 3.代理传值 #

B页面设置代理

@protocol ChangeValueDelegate <NSObject>  
      
    - (void)changeValueWithPassValue:(NSString *)passValue;  
      
    @end  
      
    @interface DetailViewController : UIViewController  
      
    @property (assign, nonatomic) id<ChangeValueDelegate> delegate;  
      
    @end

赋值

if ([self.delegate respondsToSelector:@selector(changeValueWithPassValue:)]) {  
                [self.delegate changeValueWithPassValue:@"这是传的值"];  
    }

A页面遵循代理

@interface RootViewController ()<ChangeValueDelegate>

SecondViewController *dvc = [[SecondViewController alloc] init];  
    dvc.delegate = self;  
    [self.navigationController pushViewController:dvc animated:YES];

现实代理

- (void)changeValueWithPassValue:(NSString *)titleStr{  
        NSLog(@"titleStr == %@",titleStr);  
    }

# 4.广播传值 #

A页面发送通知

NSDictionary *dict = [NSDictionary dictionaryWithObject:@"我是传的值" forKey:@"value"];  
    [[NSNotificationCenter defaultCenter] postNotificationName:@"KPassVaule" object:nil userInfo:dict];

B页面接收通知

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(getPassVauleget:) name:@"KPassVaule" object:nil];

- (void)getPassVauleget:(NSNotification *)notifi{  
        NSString *str = [notifi.userInfo objectForKey:@"value"];  
        NSLog(@"str == %@",str);  
    }

# 5.KVO传值 #

在初始化方法中加入

[_stu addObserver:self forKeyPath:@"name" options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld context:nil];

在dealloc中移除KVO监听：

[_stu removeObserver:self forKeyPath:@"name" context:nil];

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(voidvoid *)context{  
        if ([object isKindOfClass:[Student class]]) {  
            NSLog(@"_stu-old:%@",[change objectForKey:@"old"]);  
            NSLog(@"_stu-new:%@",[change objectForKey:@"new"]);  
        }  
    }

# 6.blcok反向传值 #

A页面

DetailViewController *dvc = [[DetailViewController alloc] init];  
    dvc.fontSize = _label.font.pointSize;  
    void (^mBlocks)(float value);  
    mBlocks = ^(float value){  
         _label.font = [UIFont systemFontOfSize:value];  
    };  
    [dvc changeFont:mBlocks];  
    [self presentViewController:dvc animated:YES completion:^{  
       NSLog(@"hb");  
    }];

B页面

#import <UIKit/UIKit.h>  
      
    @interface DetailViewController : UIViewController{  
        void (^_mBlock)(float value);  
    }  
      
    @property (assign, nonatomic) float fontSize;  
      
    - (void)changeFont:(void (^)(float value))mBlock;  
      
    @end

传值

_mBlock(1111.00);

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