Question

我是Objective C的新手，我无法让代表在我的代码中工作。

我有一个名为cViewController的类，在这个类中有一个UIWebView来获取网页，上面有一个按钮，它调用一个名为prodMenu的popover类。我遇到的问题是，从prodMenu类调用webpages并在父UIWebView上显示它的函数不起作用。

cViewController.h

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

@interface cViewController : UIViewController <prodMenuDelegate>{
    UIPopoverController *cpopover;
    IBOutlet UIWebView *webImageDisplay;
}
@property (nonatomic, retain) UIWebView *webImageDisplay;
@property (nonatomic, retain) UIPopoverController *cpopover;
- (IBAction)cPopoverTapped:(id)sender;
- (void) fetchWebsite:(NSString *)website; //This is the delegate method I'm trying to call in the popover class.
@end

cViewController.m

- (IBAction)cPopoverTapped:(id)sender {
    prodMenu *tp = [[prodMenu alloc] init];
    cpopover = [[UIPopoverController alloc] initWithContentViewController:tp];
    [tp release];
    CGRect rect = CGRectMake(40, 0, 50, 50);
    cpopover.popoverContentSize = CGSizeMake(250, 225);
    [cpopover presentPopoverFromRect:rect inView:self.view permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];
}

- (void)fetchWebsite:(NSString*)website{ //This function is called by prodMenu class
    NSLog(@"address: %@", website);
    NSString *urlAddress = website;
    NSURL *url = [NSURL URLWithString:urlAddress];
    NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
    [webImageDisplay loadRequest:requestObj];
    [webImageDisplay release];
}

- (void)viewDidLoad {
    [self fetchWebsite:@"http://www.yahoo.com"];
    [super viewDidLoad];
}

prodMenu.h

#import <UIKit/UIKit.h>
@protocol prodMenuDelegate;

@interface prodMenu : UIViewController{
    <prodMenuDelegate> delegate;
}
- (IBAction)radBtn:(id)sender; //This is the IBAction that calls the fetchWebsite function
@property (nonatomic, assign) id <prodMenuDelegate> delegate;
@end

@protocol prodMenuDelegate
- (void)fetchWebsite:(NSString *)website;
@end

prodMenu.m

#import "prodMenu.h"
#import "cViewController.h"

@implementation prodMenu
@synthesize delegate;

- (IBAction)radBtn:(id)sender{
    [delegate fetchWebsite:@"http://www.google.com"]; //Here is the call to the method
}

我在这里错过了调用委托方法的内容吗？没有任何错误或警告。我想要做的就是当用户按下弹出窗口视图上的按钮时，下面的父类会更改网页。提前谢谢。

Answer 1

只是一个简单的想法。您是否尝试过像这样声明委托协议

@protocol prodMenuDelegate <NSObject>
    ...
@end

？当省略＆lt;时，我经常遇到麻烦。 NSObject＆gt;。另外我认为

中缺少'id'

@interface prodMenu : UIViewController{
    <prodMenuDelegate> delegate;
}

编辑：此外，在您发布的代码中，我看不到您实际分配prodMenu代表的位置。

从popover类调用委托方法

1 个答案: