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

关键词:页面间传值iOS  阅读(19559) 赞(33)

[摘要]本文是对iOS页面间传值的方式(Delegate/NSNotification/Block/NSUserDefault)的讲解,对学习IOS苹果软件开发有所帮助,与大家分享。

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

@property(nonatomic) NSInteger flag;//当前系统标示(0:其他传值方式;1:block传值方式)

在A页面的试图控制器中

- (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

//SecondViewController.h
@protocol secondViewDelegate
-(void)showName:(NSString *)nameString;
@end

设置代理(为防止循环引用,此次采用了weak)


//SecondViewController.h
@interface SecondViewController : UIViewController
@property (nonatomic, weak)id<secondViewDelegate> delegate;
@property (nonatomic, copy) ablock block;
@end
点击按钮传递数组让其显示
//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
//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:
//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:

//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:

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

调用,显示

//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

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

@property (nonatomic, copy) ablock block;

在B试图控制器中,

- (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

- (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

//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

-(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

//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

-(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

//
//  DataSource.h
//  TestCallBack
//
//  Created by csdc-iMac on 14-7-17.
//  Copyright (c) 2014年 JuneWang. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface DataSource : NSObject
@property (nonatomic, strong) NSString *myName;
+(DataSource*)sharedDataSource;
@end
//
//  DataSource.m
//  TestCallBack
//
//  Created by csdc-iMac on 14-7-17.
//  Copyright (c) 2014年 JuneWang. All rights reserved.
//

#import "DataSource.h"

@implementation DataSource
+(DataSource *)sharedDataSource{
    static DataSource *dataSource = nil;
    static dispatch_once_t once;
    dispatch_once(&once, ^{
        dataSource = [DataSource new];
    });
    return dataSource;
}
@end

程序运行截图

A视图:

B视图

当输入姓名,并点击对应的确认按钮后,会回到A视图,并显示在B视图中输入的姓名



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