xcode iPhone，如何使用 App Delegate 变量才能像全局变量一样使用它？
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iPhone, how do usa an App Delegate variable so it can be used like global variables?
提问by Jules
Heres the code I'm using, see my error afterwards
这是我正在使用的代码，之后查看我的错误
@interface MyAppDelegate : NSObject {
NSString *userName;
}
@property (nonatomic, retain) NSString *userName;
...
@end
and in the .M file for the App Delegate you would write:
在 App Delegate 的 .M 文件中，您将编写：
@implementation MyAppDelegate
@synthesize userName;
...
@end
Then, whenever you want to fetch or write userName, you would write:
然后，无论何时您想获取或写入用户名，您都可以这样写：
MyAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
someClass.someString = appDelegate.userName; //..to fetch
appDelegate.userName = ..some NSString..; //..to write
warning: type 'id ' does not conform to the 'MyAppDelegate' protocol
警告：类型“id”不符合“MyAppDelegate”协议
What am I missing in my code ?
我的代码中缺少什么？
回答by Guy Ephraim
You should add a cast to MyAppDelegate
您应该向 MyAppDelegate 添加演员表
MyAppDelegate *appDelegate = (MyAppDelegate*)[[UIApplication sharedApplication] delegate];
MyAppDelegate *appDelegate = (MyAppDelegate*)[[UIApplication sharedApplication] delegate];
回答by Ayushi H
Yes, you can access any variable value by making it global.
是的，您可以通过将其设为全局来访问任何变量值。
For Example:
例如：
AppDelegate.h
AppDelegate.h
{
NSString *username;
}
@property (strong,nonatomic) NSString *username;
AppDelegate.m(in @implementation block)
AppDelegate.m（在@implementation 块中）
@synthesize username;
AnyViewController.h
AnyViewController.h
#import AppDelegate.h
AnyViewController.m
AnyViewController.m
//Whatever place you want to access this field value you can use it like.
AppDelegate *appdel=(AppDelegate *)[[UIApplication sharedApplication] delegate];
NSString *unm=appdel.username;
//You can get the username value here.
NSLog(@"%@",unm);
