从UIViewController更改AppDelegate的属性不起作用 [英] Change property of AppDelegate from UIViewController is not working

问题描述

我遇到一个问题，在AppDelegate内部，我创建了一个属性以在应用程序内共享价值.

I run into an issue that inside of AppDelegate, I create a property to share value within the app.

@property (nonatomic, retain) User *currentUser;

User对象的定义是

@property int points;
@property (nonatomic, copy) NSString *userName;

我有一个UIViewController A，其中一个字段显示当前用户的名称.单击一个按钮将调出UIViewController B并在UIVIewController B内部，我尝试更改值:

I have a UIViewController A with a field displaying current user's name. Click on a button will bring up UIViewController B and inside of UIVIewController B, I try to change the values:

// I print out these two values here 1
((AppDelegate*)[UIApplication sharedApplication].delegate).currentUser.userName= @"newName" ;
((AppDelegate*)[UIApplication sharedApplication].delegate).currentUser.points= 19 ;
// I print out these two values here 2

从1和2的打印输出中，userName已成功更改.但是，当我将控件从B传递回A时，UIViewController A中的userName字段尚未更新.在我的ViewController A中，我有:

From the print out at 1 and 2, the userName has been changed successfully. However, when I pass the control back to A from B, the userName field in UIViewController A has not been updated. In my ViewController A, I have:

- (void)viewWillAppear:(BOOL)animated{
   textField.text = ((AppDelegate*)[UIApplication sharedApplication].delegate).currentUser.userName;
}

有什么想法吗?

问候 锤子

更奇怪的是，第一行打印0，第二行13，第三行0，最后一行13.看起来分配永远都行不通.用户ID定义为@property int userId;.

it is more weird that, the first line prints 0, second line 13, 3rd line 0 and the last line 13. It looks like the assignment never works. User ID is defined as @property int userId;.

NSLog(@"BeforeLogin:%d",((AppDelegate*)[UIApplication sharedApplication].delegate).currentUser.userId);
NSLog(@"newUser.userId:%d",newUser.userId);
// update profile locally
((AppDelegate*)[UIApplication sharedApplication].delegate).currentUser.userId= newUser.userId ;
NSLog(@"AfterLogin:%d",((AppDelegate*)[UIApplication sharedApplication].delegate).currentUser.userId);
NSLog(@"newUser.userToken:%@",newUser.userToken);

User.h

#import <Foundation/Foundation.h>
@interface User : NSObject<HttpClientDelegate>
@property int userId; // I also try @property (assign, nonatomic, readwrite) int userId;

推荐答案

您应更改属性定义，例如

you should change your property definition e.g.,

此

@property (nonatomic, copy) NSString *userName;

与此

@property (nonatomic, strong) NSString *userName;

还查看了如何定义属性的示例

also take a look at the examples how to define properties

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