iOS页面之间传值的方式(NSUserDefault/Delegate/NSNotification/Block)

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iOS页面间传值的方式（NSUserDefault/Delegate/NSNotification/Block）

实现了以下iOS页面间传值：1.委托delegate方式；2.通知notification方式；3.block方式；4.UserDefault或者文件方式；5.单例模式方式；6.通过设置属性，实现页面间传值

在iOS开发中，我们经常会遇到页面间跳转传值的问题，现归纳总结一下：

情况1：A页面跳转到B页面

方法：

在B页面的控制器中，编写对应的属性，在A页面跳转到B页面的地方，给B的属性赋值即可

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@property(nonatomic) NSInteger flag;//当前<span id="9_nwp" style="width: auto; height: auto; float: none;"><a id="9_nwl" href="http://cpro.baidu.com/cpro/ui/uijs.php?rs=1&u=http%3A%2F%2Fwww%2Edaxueit%2Ecom%2Farticle%2F4452%2Ehtml&p=baidu&c=news&n=10&t=tpclicked3_hc&q=00007110_cpr&k=%CF%B5%CD%B3&k0=%CF%B5%CD%B3&k1=ios&k2=%BF%D8%D6%C6%C6%F7&k3=block&k4=%C8%ED%BC%FE&k5=%C8%ED%BC%FE%BF%AA%B7%A2&sid=61490806c97ccfdf&ch=0&tu=u1704338&jk=1edcfcd1d0eed3ba&cf=29&fv=16&stid=9&urlid=0&luki=7&seller_id=1&di=128" target="_blank" mpid="9" style="text-decoration: none;"><span style="color:#0000ff;font-size:14px;width:auto;height:auto;float:none;">系统</span></a></span>标示（0：其他传值方式；1：<span id="10_nwp" style="width: auto; height: auto; float: none;"><a id="10_nwl" href="http://cpro.baidu.com/cpro/ui/uijs.php?rs=1&u=http%3A%2F%2Fwww%2Edaxueit%2Ecom%2Farticle%2F4452%2Ehtml&p=baidu&c=news&n=10&t=tpclicked3_hc&q=00007110_cpr&k=block&k0=block&k1=%C8%ED%BC%FE&k2=%C8%ED%BC%FE%BF%AA%B7%A2&k3=%C6%BB%B9%FB&k4=%CF%B5%CD%B3&k5=ios&sid=61490806c97ccfdf&ch=0&tu=u1704338&jk=1edcfcd1d0eed3ba&cf=29&fv=16&stid=9&urlid=0&luki=3&seller_id=1&di=128" target="_blank" mpid="10" style="text-decoration: none;"><span style="color:#0000ff;font-size:14px;width:auto;height:auto;float:none;">block</span></a></span>传值方式）

在A页面的试图控制器中

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- (IBAction)showSecondView:(id)sender {
    SecondViewController *second = [[SecondViewController alloc] initWithNibName:@"SecondViewController"bundle:nil];
    second.delegate = self;
    second.flag = 0;
    [self presentViewController:second animated:YES completion:nil];
}

情况2：A页面跳转到B页面，B页面再跳转回A页面

主流方案：

（1）通过委托delegate的方式实现

设置协议及方法

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//SecondViewController.h

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@protocol secondViewDelegate
-(void)showName:(NSString *)nameString;
@end

设置代理(为防止循环引用，此次采用了weak)

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//SecondViewController.h

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@interface SecondViewController : UIViewController
@property (nonatomic, weak)id<secondViewDelegate> delegate;
@property (nonatomic, copy) a<span id="0_nwp"style="width: auto; height: auto; float: none;"><a id="0_nwl"href="http://cpro.baidu.com/cpro/ui/uijs.php?rs=1&u=http%3A%2F%2Fwww%2Edaxueit%2Ecom%2Farticle%2F4452%2Ehtml&p=baidu&c=news&n=10&t=tpclicked3_hc&q=00007110_cpr&k=block&k0=block&k1=%C8%ED%BC%FE&k2=%C8%ED%BC%FE%BF%AA%B7%A2&k3=%C6%BB%B9%FB&k4=%CF%B5%CD%B3&k5=ios&sid=61490806c97ccfdf&ch=0&tu=u1704338&jk=1edcfcd1d0eed3ba&cf=29&fv=16&stid=9&urlid=0&luki=3&seller_id=1&di=128"target="_blank"mpid="0"style="text-decoration: none;"><span style="color:#0000ff;font-size:14px;width:auto;height:auto;float:none;">block</span></a></span> block;
@end

点击按钮传递数组让其显示

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//SecondViewController.m
- (IBAction)delegateMethod:(id)sender {
    if([self notEmpty]) {
        [self.delegate showName:self.nameTextField.text];
        [self dismissViewControllerAnimated:YES completion:nil];
    }else{
        [self showAlert];
    }
}

调用，显示

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//RootViewController.m
-(void)showName:(NSString *)nameString{
    self.nameLabel.text = nameString;
}

最重要也是最容易忽略的，就是一定要设置delegate的指向。

效果：

（2）通过通知notification的方式实现

在B页面的控制器中，发送通知：

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//SecondViewController.m
- (IBAction)notificationMethod:(id)sender {
    if([self notEmpty]) {
        [[NSNotificationCenter defaultCenter] postNotificationName:@"ChangeNameNotification"object:self userInfo:@{@"name":self.nameTextField.text}];
        [self dismissViewControllerAnimated:YES completion:nil];
    }else{
        [self showAlert];
    }
}

在A页面的控制器中，注册通知：

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//RootViewController.m
- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(ChangeNameNotification:) name:@"ChangeNameNotification"object:nil];
}

当我们不使用时，要记得删掉通知：

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//RootViewController.m
-(void)dealloc{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

调用，显示

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//RootViewController.m
 
-(void)ChangeNameNotification:(NSNotification*)notification{
    NSDictionary *nameDictionary = [notification userInfo];
    self.nameLabel.text = [nameDictionary objectForKey:@"name"];
}

（3）block方式实现

分析：

在B试图控制器中，定义一个block，参数为字符串

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//SecondViewController.h
typedefvoid (^ablock)(NSString *str);

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//SecondViewController.h
 
@property (nonatomic, copy) ablock block;

在B试图控制器中，

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- (IBAction)blockMethod:(id)sender {
    if([self notEmpty]) {
        if(self.block) {
            self.block(self.nameTextField.text);
            [self dismissViewControllerAnimated:YES completion:nil];
        }
    }else{
        [self showAlert];
    }
}

在A试图显示，回调block

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- (IBAction)showSecondWithBlock:(id)sender {
    SecondViewController *second = [[SecondViewController alloc] initWithNibName:@"SecondViewController"bundle:nil];
    [self presentViewController:second animated:YES completion:nil];
    second.block = ^(NSString *str){
        self.nameLabel.text = str;
    };
}

链接一篇描述block回调挺有意思的文章：http://blog.csdn.net/mobanchengshuang/article/details/11751671

在查阅资料的过程中，我还看到了以下几种方案：

（1）使用SharedApplication,定义一个变量来传递（感觉和单例的方式一样）

（2）使用文件，或者NSUserdefault来传递

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//通过文件或者UserDefault方式存值(感觉不太适合此类传值，如果要用文件或者UserDefault方式存值的话，可以考虑此方式)
- (IBAction)userDefaultMethod:(id)sender {
    if([self notEmpty]) {
        [[NSUserDefaults standardUserDefaults] setObject:self.nameTextField.text forKey:@"myNameText"];
        [self dismissViewControllerAnimated:YES completion:nil];
    }else{
        [self showAlert];
    }
}

在A试图控制器显示

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-(void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
    //如果想测试通过UserDefault方式传值或者通过单例方式传值，取消以下注释即可
/*
    if ([[[NSUserDefaults standardUserDefaults] objectForKey:@"myNameText"] length] != 0) {
        self.nameLabel.text = [[NSUserDefaults standardUserDefaults] objectForKey:@"myNameText"];
        [[NSUserDefaults standardUserDefaults] setObject:@"" forKey:@"myNameText"];
    }
    DataSource *dataSource = [DataSource sharedDataSource];
    if ([dataSource.myName length] != 0) {
        self.nameLabel.text = dataSource.myName;
        dataSource.myName = @"";
    }
*/
}

（3）通过一个单例的class来传递

B试图控制器

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//通过单例方式传值(感觉不太适合此类传值，如果要用单例方式传值的话，可以考虑此方式)
- (IBAction)singletonMethod:(id)sender {
    if([self notEmpty]) {
        DataSource *dataSource = [DataSource sharedDataSource];
        dataSource.myName = self.nameTextField.text;
        [self dismissViewControllerAnimated:YES completion:nil];
    }else{
        [self showAlert];
    }
}

A试图控制器显示

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-(void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
    //如果想测试通过UserDefault方式传值或者通过单例方式传值，取消以下注释即可
/*
    if ([[[NSUserDefaults standardUserDefaults] objectForKey:@"myNameText"] length] != 0) {
        self.nameLabel.text = [[NSUserDefaults standardUserDefaults] objectForKey:@"myNameText"];
        [[NSUserDefaults standardUserDefaults] setObject:@"" forKey:@"myNameText"];
    }
    DataSource *dataSource = [DataSource sharedDataSource];
    if ([dataSource.myName length] != 0) {
        self.nameLabel.text = dataSource.myName;
        dataSource.myName = @"";
    }
*/
}
@end

这里面用到了单例模式，编写了DataSource这个类，存放数据

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//
//  DataSource.h
//  TestCallBack
//
//  Created by csdc-iMac on 14-12-24.
//  Copyright (c) 2014年 赵黛阳. All rights reserved.
//
 
#import <Foundation/Foundation.h>
 
@interface DataSource : NSObject
@property (nonatomic, strong) NSString *myName;
+(DataSource*)sharedDataSource;
@end

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//
//  DataSource.m
//  TestCallBack
//
//  Created by csdc-iMac on 14-12-24.
//  Copyright (c) 2014年 赵黛阳. All rights reserved.
//
 
#import "DataSource.h"
 
@implementation DataSource
+(DataSource *)sharedDataSource{
    staticDataSource *dataSource = nil;
    staticdispatch_once_t once;
    dispatch_once(&once, ^{
        dataSource = [DataSource new];
    });
    returndataSource;
}
@end

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