Question

我正在尝试使用委托将viewControllerA中的简单数据发送到viewControllerB，但无法在我的代码中找到问题。这是代码

ViewControllerA.h

中的

#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

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

这里是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

从未调用已实现的函数-(void) addItem: (ViewControllerA *)controller data:(NSString *)item。我遗漏了什么？提前致谢

Answer 1

你在使用故事板吗？如果是的话，你只需按错了按钮：storyboard自己初始化视图控制器，所以你的代码：

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

在一些未使用的视图控制器上设置委托。使用segues，不要试图重新发明轮子。

使用委托将数据从控制器传递到控制器

1 个答案: