最初的回应开始:
...其他人可能对此有更多要说的,但我不确定为什么您需要在这里使用对象关联。您当然可以使用常规子类化将另一个按钮作为属性添加到按钮中,这就是我将采取的路线。 ...
编辑如下:
我以为我直接子类化了一个UI控件,但是当我去寻找代码时我发现我错了。 @Joe 在评论中正确地指出直接子类化 UI 控件存在问题。
通过创建一个包装类来保存按钮及其相关的删除按钮,我能够在不使用关联对象的情况下实现类似您所描述的功能。它可以工作,但不是很灵活,所以我通常会推荐@Joe 的方法作为更好的解决方案。
这是相关代码:
为了简单起见,我将所有代码都放入了 appDelegate 中。我不建议在现实生活中这样做。
AppDelegate.m:
@implementation AppDelegate
@synthesize window = _window;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
self.window.backgroundColor = [UIColor whiteColor];
UIButton *toggleDeleteButtons = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[toggleDeleteButtons setFrame:CGRectMake(20, 45, 280, 45)];
[toggleDeleteButtons setTitle:@"Toggle Delete" forState:UIControlStateNormal];
[toggleDeleteButtons addTarget:self action:@selector(toggleDeleteButtonAction) forControlEvents:UIControlEventTouchUpInside];
[[self window] addSubview:toggleDeleteButtons];
ButtonWrapper *myButtonWrapper = [[ButtonWrapper alloc] init];
[[myButtonWrapper button] setFrame:CGRectMake(20, 100, 200, 45)];
[[myButtonWrapper button] setTitle:@"This is my button" forState:UIControlStateNormal];
[[myButtonWrapper deleteButton] addTarget:self action:@selector(buttonDeleteRequested:) forControlEvents:UIControlEventTouchUpInside];
[[myButtonWrapper deleteButton] setTag:0];
[[self window] addSubview:[myButtonWrapper button]];
buttonWrapper1 = myButtonWrapper;
// Added instance called anotherButtonWrapper with tag 1, as above
// Added instance called stillAnotherButtonWrapper with tag 2, as above
[self.window makeKeyAndVisible];
return YES;
}
- (void)toggleDeleteButtonAction {
static BOOL deleteButtonsShown;
[buttonWrapper1 showDeleteButton:!deleteButtonsShown];
[buttonWrapper2 showDeleteButton:!deleteButtonsShown];
[buttonWrapper3 showDeleteButton:!deleteButtonsShown];
deleteButtonsShown = !deleteButtonsShown;
}
- (void)buttonDeleteRequested:(UIButton *)deleteButton {
// delete the specified button here
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Delete" message:[NSString stringWithFormat:@"Delete was pressed on button %i",[deleteButton tag]]delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
}
ButtonWrapper.m:
@implementation ButtonWrapper
@synthesize button;
@synthesize deleteButton;
- (ButtonWrapper *)init {
ButtonWrapper *newWrapper = [ButtonWrapper alloc];
UIButton *myButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[myButton setFrame:CGRectZero];
UIButton *myDeleteButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[myDeleteButton setFrame:CGRectMake(0, 0, 100, 40)];
[myDeleteButton setTitle:@"Delete" forState:UIControlStateNormal];
[myDeleteButton setHidden:TRUE];
[myButton addSubview:myDeleteButton];
[newWrapper setButton:myButton];
[newWrapper setDeleteButton:myDeleteButton];
return newWrapper;
}
- (void)showDeleteButton:(BOOL)showButton {
if (showButton) {
[[self deleteButton] setHidden:FALSE];
[[self deleteButton] setEnabled:TRUE]; }
else {
[[self deleteButton] setHidden:TRUE];
[[self deleteButton] setEnabled:FALSE];
}
}
@end
该解决方案不需要我实现所有 UI 属性,但它确实需要额外的工作来连接嵌入式委托,这很麻烦。可能有一种方法可以在初始化时将委托传递到包装器中,但我无法使其工作。