iOS 页面之间的传值

ios页面之间的传值是很常用的，常用的方法有这几种：delegate、block。

下面就以 viewController和nextViewController之间的传值为例，过程是这样的：

1、viewController pushViewController到nextViewController。

2、nextViewController再popViewControllerAnimated回到viewController，同时将

nextViewController的输入（用户名）回传给viewController。

一、delegate（代理）

1、在NextViewController实现代理方法：

这是用的比较普遍也是比较早的，需要声明一个代理：

//NextViewController.h

@protocol NextViewControllerDelegate <NSObject>

- (void) passUserName: (NSString *)name;

@end

@interface NextViewController :UIViewController

@property (nonatomic,weak)id<NextViewControllerDelegate> delegate;

@end

//NextViewController.m

....

在退出页面时调用

- (void) handlePopController {

    if (self.delegate && [self.delegaterespondsToSelector:@selector(passUserName:)]) {

        [self.delegatepassUserName:@"wqm"];

    }

}

2、在viewController中实现代理方法

//在进入NextViewController页面时调用handlPushViewController

- (void)handlPushViewController {

    NextViewController *nextVC = [[NextViewControlleralloc]init];

    nextVC.delegate =self;

    [self.navigationControllerpushViewController:nextVCanimated:YES];

}

#pragma mark NextViewControllerDelegate

- (void)passUserName:(NSString *)name {

    NSLog(@"His name is %@", name);

}

二、block实现：

1、NextViewController定义一个block的成员变量

//NextViewController.h

@interface NextViewController :UIViewController

@property (nonatomic,copy)void (^passName) (NSString *name);

@end

//NextViewController.m

- (void) handlePopController {

    self.passName(@"wqm");

}

2、ViewController给block赋值

//ViewController.m

//在进入NextViewController页面时调用handlPushViewController

- (void)handlPushViewController {

    NextViewController *nextVC = [[NextViewControlleralloc]init];

    nextVC.passName = ^(NSString *name) {

        NSLog(@"His name is %@", name);

    };

    [self.navigationControllerpushViewController:nextVCanimated:YES];

}