IOS 界面之间传值总结

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

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

//SecondViewController.h

@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
1.//RootViewController.m

- (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
![](http://upload-images.jianshu.io/upload_images/1116084-894d72c1018d8fde.jpg?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

//SecondViewController.h

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

设置代理(为防止循环引用,此处采用了weak)

//SecondViewController.h

@interface SecondViewController : UIViewController
@property  (nonatomic, weak)id<secondViewDelegate> delegate;
@property (nonatomic, copy) ablock block;
@end

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

//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。 (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
block介绍:http://blog.csdn.net/totogo2010/article/details/7839061
链接一篇描述block回调挺有意思的文章: http://blog.csdn.net/mobanchengshuang/article/details/11751671
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,当输入名字,点击对应的确定按钮后

- (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;
};
}

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

import <Foundation/Foundation.h>

@interface DataSource : NSObject
@property (nonatomic, strong) NSString myName;
+(DataSource
)sharedDataSource;
@end````

@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:
![\](http://upload-images.jianshu.io/upload_images/1116084-c6846f597e3ff114.jpg?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)
B视图
![\](http://upload-images.jianshu.io/upload_images/1116084-108396089dfd0a1c.jpg?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)
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
![\](http://upload-images.jianshu.io/upload_images/1116084-75df3ddccd8106ef.jpg?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)
祝:玩得开心,有什么别的办法或者不正确的地方,欢迎指正。    

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