在另一个类中访问NSApplications委派？ [英] Accessing an NSApplications delegate in another class?

问题描述

我目前正在尝试写我的第一个CoreData应用程序，需要访问的应用程序委派的一些东西。所以我试图在我的委托，我想读一个小变量，以确定我是否获得正确的代理。但是，似乎我无法访问我的代理，并创建一个新的。
这是我的代码：

  // delegate.h 
 #import< Cocoa / Cocoa。 h。 
 
 @interface delegate_TestAppDelegate：NSObject< NSApplicationDelegate> {
 @private 
 NSWindow * window; 
 NSString * myString; 
} 
 
 @property（assign）IBOutlet NSWindow * window; 
 @property（retain）NSString * myString; 
 
 @end 
 
 //delegate.m 
 #importdelegate_TestAppDelegate.h
 
 @implementation delegate_TestAppDelegate 
 
 @synthesize window，myString; 
 
  - （void）applicationDidFinishLaunching：（NSNotification *）aNotification 
 {
 self.myString = @Hello，World; 
 NSLog（@在委托：％@，self.myString）; 
} 
 
 @end 
 
 //MyClass.h 
 #import< Foundation / Foundation.h> 
 #importdelegate_TestAppDelegate.h
 
 
 @interface MyClass：NSObject {
 @private 
 delegate_TestAppDelegate * del; 
} 
  - （IBAction）click：（id）sender; 
 
 @end 
 
 //MyClass.m 
 #importMyClass.h
 
 @implementation MyClass 
 
  - （id）init 
 {
 self = [super init]; 
 if（self）{
 del = [[NSApplication sharedApplication] delegate]; 
} 
 
 return self; 
} 
 
  - （void）dealloc 
 {
 [super dealloc]; 
} 
 
  - （IBAction）click：（id）sender {
 NSLog（@Click：％@，del.myString）;奇怪的是，这段代码返回In delegate：，然后单击下一步，然后单击下一步 Hello，World，但点击：（null）
我的错误在哪里？
解决方案
在任何分配给应用程序的委托属性之前，重新分配 del 。我建议你摆脱 del 指针，只需调用 [[NSApplication sharedApplication] delegate] 时间你需要委托。
 
I'm currently trying to write my first CoreData-Application, which needs to access the applications delegate for some stuff. So I was trying to make a little variable inside my delegate which I wanted to read to determine if I got the correct delegate. However, it seems like I'm unable to access my delegate and create a new one instead.
Here is my code:
//delegate.h
#import <Cocoa/Cocoa.h>

@interface delegate_TestAppDelegate : NSObject <NSApplicationDelegate> {
@private
    NSWindow *window;
    NSString * myString;
}

@property (assign) IBOutlet NSWindow *window;
@property (retain) NSString * myString;

@end

//delegate.m
#import "delegate_TestAppDelegate.h"

@implementation delegate_TestAppDelegate

@synthesize window, myString;

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
    self.myString = @"Hello, World";
    NSLog(@"In delegate: %@", self.myString);
}

@end

//MyClass.h
#import <Foundation/Foundation.h>
#import "delegate_TestAppDelegate.h"


@interface MyClass : NSObject {
@private
    delegate_TestAppDelegate * del;
}
- (IBAction)click:(id)sender;

@end

//MyClass.m
#import "MyClass.h"

@implementation MyClass

- (id)init
{
    self = [super init];
    if (self) {
        del = [[NSApplication sharedApplication] delegate];
    }

    return self;
}

- (void)dealloc
{
    [super dealloc];
}

- (IBAction)click:(id)sender {
    NSLog(@"Click: %@", del.myString);
}
@end
Strangely enough, this code returns "In delegate: Hello, World", but "Click: (null)"
Where is my error?
解决方案
I suspect you're assigning del before anything has been assigned to the delegate property of the application.  I'd recommend you get rid of the del pointer altogether, and simply call [[NSApplication sharedApplication] delegate] each time you need the delegate.

                        
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