Question

我正在撰写的这个应用程序部分遇到很多问题，我相信这里的人都会厌倦我，所以我会尝试在这篇文章中解决我的所有问题。我正在开发一个行为像照片库的应用程序，我正在实施让用户从其库中删除照片的选项。为了做到这一点，我决定在每张照片上放置一个隐形按钮。当用户点击“编辑”按钮时，每张图片上的隐藏删除按钮变为活动状态。为简单起见，我在每个隐藏按钮上使用相同的IBOutlet，并且我在Interface Builder中适当地标记了每个按钮。当用户点击图片上的按钮时，会出现警告视图，询问他们是否确实要删除它。如果他们单击是，我调用removeObjectAtIndex并从UI中删除图像。但是，当我在警报视图中单击“是”时，我从Xcode收到错误说明：

2012-04-04 11：26：40.484 AppName [608：f803] - [UIButton setImage：]：无法识别的选择器发送到实例0x6a922c0

2012-04-04 11：26：40.485 AppName [608：f803] 由于未捕获的异常'NSInvalidArgumentException'而终止应用，原因：' - [UIButton setImage：]：无法识别的选择器发送到实例0x6a922c0' *

我一直试图找出造成这种情况的原因几个小时现在无济于事。我没有在我的代码中的任何地方设置UIButton的图像。我在IB中做过，但我只是将按钮类型设置为Custom，使它们看起来不可见。我将在下面发布我的整个文件，我在代码中找不到任何问题，所以非常感谢任何帮助！谢谢。编辑以下是代码的当前版本：

    - (IBAction)grabImage {
    self.imgPicker = [[UIImagePickerController alloc] init];
    self.imgPicker.delegate = self;
    self.imgPicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
        _popover = [[UIPopoverController alloc] initWithContentViewController:imgPicker];
        [_popover presentPopoverFromRect:self.imageView.bounds inView:self.imageView permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
    } 

    else {
        [self presentModalViewController:imgPicker animated:YES];
    }
    [self.imgPicker resignFirstResponder];
}
// Sets the image in the UIImageView
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)img editingInfo:(NSDictionary *)editInfo {
    if (imageView.image == nil) {
        imageView.image = img;

        self.array = [NSMutableArray arrayWithObject:[NSData dataWithData:UIImagePNGRepresentation(imageView.image)]];

        [picker dismissModalViewControllerAnimated:YES];
        [self.popover dismissPopoverAnimated:YES];
        return;

    }

    if (imageView2.image == nil) {
        imageView2.image = img;
        NSLog(@"The image is a %@", imageView);
        [self.array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView2.image)]];

        [picker dismissModalViewControllerAnimated:YES];
        [self.popover dismissPopoverAnimated:YES];
        return;
    }

    if (imageView3.image == nil) {
        imageView3.image = img;

        [self.array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView3.image)]];

        [picker dismissModalViewControllerAnimated:YES];
        [self.popover dismissPopoverAnimated:YES];
        return;
    }

    if (imageView4.image == nil) {
        imageView4.image = img;

        [self.array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView4.image)]];

        [picker dismissModalViewControllerAnimated:YES];
        [self.popover dismissPopoverAnimated:YES];
        return;
}
}

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.title = NSLocalizedString(@"Photo Gallery", @"Photo Gallery");
        self.tabBarItem.image = [UIImage imageNamed:@"42-photos.png"];
    }
    return self;
}
////start of saving////


- (void)applicationDidEnterBackground:(UIApplication*)application {
    NSLog(@"Image on didenterbackground: %@", imageView);
    self.array = [NSMutableArray arrayWithObject:[NSData dataWithData:UIImagePNGRepresentation(imageView.image)]];

    [self.array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView2.image)]];
     [self.array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView3.image)]];
      [self.array addObject:[NSData dataWithData:UIImagePNGRepresentation(imageView4.image)]];

            [self.user setObject:self.array forKey:@"images"];
    [user synchronize];

            }

- (void)viewDidLoad
    {
        self.user = [NSUserDefaults standardUserDefaults];
        NSLog(@"It is %@", self.user);
        self.array = [[self.user objectForKey:@"images"]mutableCopy];
        imageView.image = [[UIImage alloc] initWithData:[self.array objectAtIndex:0]];
        imageView2.image = [[UIImage alloc] initWithData:[self.array objectAtIndex:1]];
        imageView3.image = [[UIImage alloc] initWithData:[self.array objectAtIndex:2]];
        imageView4.image = [[UIImage alloc] initWithData:[self.array objectAtIndex:3]];



        UIApplication *app = [UIApplication sharedApplication];
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(applicationDidEnterBackground:)
                                                     name:UIApplicationDidEnterBackgroundNotification
                                                   object:app];

        backToGalleryButton.hidden = YES;
        tapToDeleteLabel.hidden = YES;
        deleteButton1.hidden = YES;
        [super viewDidLoad];

    }




///// shows the hidden and invisible "delete" button over each photo.
- (IBAction)editButtonPressed:(id)sender {
    grabButton.hidden = YES;
    editButton.hidden = YES;
    backToGalleryButton.hidden = NO;
    tapToDeleteLabel.hidden = NO;
    deleteButton1.hidden = NO;
}
////

// This is when the user taps on the image to delete it.
- (IBAction)deleteButtonPressed:(id)sender {
    NSLog(@"Sender is %@", sender);
    UIAlertView *deleteAlertView = [[UIAlertView alloc] initWithTitle:@"Delete"
                                                              message:@"Are you sure you want to delete this photo?"
                                                             delegate:self
                                                    cancelButtonTitle:@"No"
                                                    otherButtonTitles:@"Yes", nil];
    [deleteAlertView show];
    int imageIndex = ((UIButton *)sender).tag;
    deleteAlertView.tag = imageIndex;

}

- (void)alertView: (UIAlertView *) alertView 
clickedButtonAtIndex: (NSInteger) buttonIndex
{


    if (buttonIndex != [alertView cancelButtonIndex]) {
        NSLog(@"User Clicked Yes. Deleting index %d of %d", alertView.tag, [array count]);
        NSLog(@"The tag is %i", alertView.tag);
        [self.array removeObjectAtIndex: alertView.tag];
        NSLog(@"After deleting item, array count  = %d", [array count]);
    NSLog(@"Returned view is :%@, in view: %@", [self.view viewWithTag:alertView.tag], self.view);
        ((UIImageView *)[self.view viewWithTag:alertView.tag]).image =nil;
    }

    [self.user setObject:self.array forKey:@"images"];
}

更新：我添加了断点，并发现((UIImageView *)[self.view viewWithTag:alertView.tag]).image =nil;是导致崩溃的行，我仍然无法弄清楚原因。

Answer 1

我没有看到您粘贴到问题中的任何代码中都调用了setImage:，但我可以告诉您：UIButton的{{1}}方法实际上需要一个按钮将州作为第二个参数。

e.g。

[UIButton setImage: forState:]

我已经为您链接了Apple的文档。

如果您对setImage的来电没有第二个参数，则可以解释您所看到的“无法识别的选择器错误”。

Answer 2

这是@MichaelDautermann的扩展，他非常清楚UIButton有一个setImage：forState：方法，但没有setImage方法。但是，您正在调用set image。不是按钮，而是当你说imageView.image和imageView2.image。这将调用图像视图的setter方法。我会设置一个断点（或使用NSLog和％@项）来确保imageView实际上是一个imageView而不是一个按钮。如果它从某种程度上改变了你，这可能导致问题。只需在这两行设置一个断点，看看你是否通过它们。

此外，如果Xcode没有弹出到实际导致问题的那一行，请检查崩溃日志。符号化，日志将为您提供行号。或者，一种不太直接的方法是在答案中提供的方法的末尾设置断点，并查看您通过的数量。一旦崩溃，您可以缩小导致您悲伤的方法，然后开始在方法中设置断点，直到您到达相关的行。

的更新： 的你在评论中说过（（UIImageView *）[self.view viewWithTag：alertView.tag]）。image = nil就是你所拥有的，但是self.view是一个UIControl。更改演员表不会影响结果。 UIImageView的图像是你试图删除UIControl的子视图吗？如果没有，你永远不会从viewWithTag返回图像视图。通常，self.view指的是一个视图控制器的视图，所以如果你得到一个UIControl，我的假设是你的整个视图是一个UIControl，或者你在错误的类中这样做。你在做哪个类，它的子类是什么？看来你在视图控制器中这样做了，但我只是想确定一下。而且，在任何一种情况下（UIControl或UIImageView），两个类都不响应setImage。

Xcode无法识别的选择器错误

2 个答案: