使用委託

Question

我試圖從viewControllerA發送簡單的數據使用委託viewControllerB卻找不到我code.here問題從controllerA將數據傳遞到controllerB是ViewControllerA.h

#import <UIKit/UIKit.h> 

@class ViewControllerA; 

@protocol viewControllerADelegate <NSObject> 
-(void) addItem: (ViewControllerA *)controller data:(NSString *)item; 
@end 

@interface ViewControllerA : UIViewController 
- (IBAction)buttonPressed:(id)sender; 

@property (assign) id<viewControllerADelegate> delegate; 
@end 

代碼

在ViewControllerA.m

#import "ViewControllerA.h" 

@interface ViewControllerA() 

@end 

@implementation ViewControllerA 
@synthesize delegate; 

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil 
{ 
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; 
if (self) { 
    // Custom initialization 
} 
return self; 
} 

- (void)viewDidLoad 
{ 
[super viewDidLoad]; 
// Do any additional setup after loading the view. 

} 

- (void)viewDidUnload 
{ 
[super viewDidUnload]; 
// Release any retained subviews of the main view. 
} 
- (BOOL)shouldAutorotateToInterfaceOrientation:  (UIInterfaceOrientation)interfaceOrientation 
{ 
return (interfaceOrientation == UIInterfaceOrientationPortrait); 
} 

- (IBAction)buttonPressed:(id)sender { 
[self.delegate addItem:self data:@"this is data"]; 

    } 
@end 

，這裏是ViewControllerB.h

#import <UIKit/UIKit.h> 
#import "ViewControllerA.h" 

@interface ViewControllerB : UIViewController<viewControllerADelegate> 

@end 

和ViewControllerB.m

#import "ViewControllerB.h" 
#import "ViewControllerA.h" 

@interface ViewControllerB() 

@end 

@implementation ViewControllerB 

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil 
{ 
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; 
if (self) { 
    // Custom initialization 
} 
return self; 
} 

- (void)viewDidLoad 
{ 
[super viewDidLoad]; 
// Do any additional setup after loading the view. 
ViewControllerA *vba = [[ViewControllerA alloc]init]; 
[vba setDelegate:self]; 

} 

- (void)viewDidUnload 
{ 
[super viewDidUnload]; 
// Release any retained subviews of the main view. 
} 

- (BOOL)shouldAutorotateToInterfaceOrientation: (UIInterfaceOrientation)interfaceOrientation 
{ 
return (interfaceOrientation == UIInterfaceOrientationPortrait); 
} 
-(void) addItem: (ViewControllerA *)controller data:(NSString *)item{ 
NSLog(@"delegate function called"); 
} 

@end 

所實現的功能-(void) addItem: (ViewControllerA *)controller data:(NSString *)item是從來沒有called.Am我失去了一些東西？在此先感謝

Answer 1

您使用故事板？如果是的話，你只需按錯鍵：故事板自身的初始化視圖控制器，所以你的代碼：

ViewControllerA *vba = [[ViewControllerA alloc]init]; 
[vba setDelegate:self]; 

只設置委託一些未使用的視圖控制器上。 使用segues，不要嘗試重新發明輪子。