如何从 UIbutton 选择器调用方法？

Question

如何从下面的按钮选择器代码中调用此方法：

- (void)displayEditorForImage:(UIImage *)imageToEdit

{

    AFPhotoEditorController *editorController = [[AFPhotoEditorController alloc] initWithImage:imageToEdit];

    [editorController setDelegate:self];

    [self presentViewController:editorController animated:YES completion:nil];

}

这是我尝试调用该方法的 UIButton：

//edit button
UIButton *editButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[editButton addTarget:self
               action:@selector(editBtnTouch)
     forControlEvents:UIControlEventTouchDown];

[editButton setTitle:@"Effects" forState:UIControlStateNormal];


**// the following line shows the selector where I'm unsure how to call the method from the code above**
if ([[UIScreen mainScreen] respondsToSelector:@selector(displayEditorForImage:)] &&
        ([UIScreen mainScreen].scale == 2.0)) {
        // Retina display
        editButton.frame = CGRectMake(220.0, 320.0, 60.0, 40.0);


} else {
    editButton.frame = CGRectMake(220.0, 315.0, 60.0, 40.0);
}

[self.view addSubview:editButton];

感谢您的帮助

Answer 1

当您添加到按钮的选择器被调用时，如果选择器允许，按钮本身将作为第一个参数传递。为了获得对您的图像的引用，您需要这样做（假设您想要的图像是按钮的背景图像）：

- (void)displayEditorForImage:(UIButton*)sender {
    UIImage* imageToEdit = [sender backgroundImageForState:UIControlStateNormal];
    AFPhotoEditorController *editorController = [[AFPhotoEditorController alloc] initWithImage:imageToEdit];

    [editorController setDelegate:self];

    [self presentViewController:editorController animated:YES completion:nil];
}

或者您需要创建一个自定义 UIButton，它具有关联图像的额外属性，然后只需通过选择器中的按钮访问图像：

- (void)displayEditorForImage:(UIButton*)sender {
    if([sender isKindOfClass:[YourCustomButtonClass class]]) {
        UIImage* imageToEdit = ((YourCustomButtonClass*)sender).customImageProperty;

        AFPhotoEditorController *editorController = [[AFPhotoEditorController alloc] initWithImage:imageToEdit];

        [editorController setDelegate:self];

        [self presentViewController:editorController animated:YES completion:nil];
    }
}

编辑：

您似乎对如何使UIButton 在被点击时调用方法感到困惑。您需要将定义方法的对象添加为按钮的目标（在本例中为self），将方法添加为选择器，并在点击按钮时调用该方法使用UIControlEventTouchUpInside。所以你的代码是：

[editButton addTarget:self action:@selector(displayEditorForImage:) forControlEvents:UIControlEventTouchUpInside];