iOS页面间传值的方式(Delegate/NSNotification/Block/NSUserDefault)
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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
@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
//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.htypedef 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DataBase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
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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