iPhone，如何使用App Delegate变量，以便可以像全局变量一样使用它? [英] iPhone, how do usa an App Delegate variable so it can be used like global variables?

问题描述

这里是我正在使用的代码，之后会看到我的错误

Heres the code I'm using, see my error afterwards

@interface MyAppDelegate : NSObject  {
  NSString *userName;
}
@property (nonatomic, retain) NSString *userName;
...
@end

，并在App Delegate的.M文件中编写:

and in the .M file for the App Delegate you would write:

@implementation MyAppDelegate
@synthesize userName;
...
@end

然后，每当您要获取或写入用户名时，您都将编写:

Then, whenever you want to fetch or write userName, you would write:

MyAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
someClass.someString = appDelegate.userName;  //..to fetch
appDelegate.userName = ..some NSString..;     //..to write

警告:键入"id"不符合"MyAppDelegate"协议

我的代码中缺少什么?

推荐答案

您应将演员表添加到MyAppDelegate

You should add a cast to MyAppDelegate

MyAppDelegate *appDelegate = (MyAppDelegate*)[[UIApplication sharedApplication] delegate];

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