UIButton addTarget:action:forControlEvents: 结果 [NSObject doesNotRecognizeSelector:]

Question

我尝试了很多东西，仍然没有结果。

所以我在 UIViewController 的子类中以编程方式创建了以下按钮：

    rightButton = [UIButton buttonWithType:UIButtonTypeCustom];
    rightButton.frame = CGRectMake(0.0, 0.0, 110.0, 40.0);
    rightButton.titleLabel.font = [UIFont fontWithName:GAME_FONT_NAME_STRING size:20.0];
    [rightButton setTitle:@"MyTitle" forState:UIControlStateNormal];
    rightButton.backgroundColor = [UIColor clearColor];
    [rightButton setTitleColor:[UIColor greenColor] forState:UIControlStateNormal];
    [rightButton setTitleColor:[UIColor blackColor] forState:UIControlStateHighlighted];
    [rightButton setBackgroundImage:normalImage forState:UIControlStateNormal];
    [rightButton setBackgroundImage:highlightedImage forState:UIControlStateHighlighted];
    [rightButton addTarget:self action:@selector(myButton) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:rightButton];

选择器在哪里：

- (void)myButton;

我什么都试过了：

- (void)myButton;
- (void)myButton:(id)sender;
- (void)myButton:(id)sender forEvent:(UIEvent *)event;
- (IBAction)myButton;
- (IBAction)myButton:(id)sender;
- (IBAction)myButton:(id)sender forEvent:(UIEvent *)event;

当然还有相应的选择器：

[rightButton addTarget:self action:@selector(myButton) forControlEvents:UIControlEventTouchUpInside];
[rightButton addTarget:self action:@selector(myButton:) forControlEvents:UIControlEventTouchUpInside];
[rightButton addTarget:self action:@selector(myButton:forEvent:) forControlEvents:UIControlEventTouchUpInside];
[rightButton addTarget:self action:@selector(myButton) forControlEvents:UIControlEventTouchUpInside];
[rightButton addTarget:self action:@selector(myButton:) forControlEvents:UIControlEventTouchUpInside];
[rightButton addTarget:self action:@selector(myButton:forEvent:) forControlEvents:UIControlEventTouchUpInside];

结果总是一个未捕获的异常 - [NSObject doesNotRecognizeSelector:]。然而，程序通常的回溯是：

#0  0x92a6bedb in objc_msgSend ()
#1  0x03b0a430 in ?? ()
#2  0x00306b4e in -[UIControl sendAction:to:forEvent:] ()
#3  0x00308d6f in -[UIControl(Internal) _sendActionsForEvents:withEvent:] ()
#4  0x00307abb in -[UIControl touchesEnded:withEvent:] ()
#5  0x002bcddf in -[UIWindow _sendTouchesForEvent:] ()
#6  0x002a67c8 in -[UIApplication sendEvent:] ()
#7  0x002ad061 in _UIApplicationHandleEvent ()
#8  0x02498d59 in PurpleEventCallback ()
#9  0x01cabb80 in CFRunLoopRunSpecific ()
#10 0x01caac48 in CFRunLoopRunInMode ()
#11 0x02497615 in GSEventRunModal ()
#12 0x024976da in GSEventRun ()
#13 0x002adfaf in UIApplicationMain ()

那么那个按钮有什么问题呢？

PS：我使用的是 iPhone SDK 3.1.3

---

更新！

AppDelegate 中的以下代码（接口中没有声明）：

- (void)applicationDidFinishLaunching:(UIApplication *)application {
    UIButton *test = [[UIButton alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 100.0)];
    [test setTitle:@"Title" forState:UIControlStateNormal];
    UIImage *bg = [UIImage imageNamed:...];
    [test setBackgroundImage:bg forState:UIControlStateNormal];
    [test addTarget:self action:@selector(testAction) forControlEvents:UIControlEventTouchUpInside];
    [window addSubview:test];
    [test release];
    [window makeKeyAndVisible];
}

- (void)testAction {
    NSLog(@"Write something...");
}

完美运行！

但如果我用相同的代码创建一个空的 UIViewController：

- (void)viewDidLoad {
    UIButton *test = [[UIButton alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 100.0)];
    [test setTitle:@"Title" forState:UIControlStateNormal];
    UIImage *bg = [UIImage imageNamed:...];
    [test setBackgroundImage:bg forState:UIControlStateNormal];
    [test addTarget:self action:@selector(testAction) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:test];
    [test release];
    [window makeKeyAndVisible];
}

- (void)testAction {
    NSLog(@"Write something...");
}

我收到了这个神秘的错误。 :-( 救命！

Answer 1

myButton 在哪里被声明？ 如果是合成的，那么代替

rightButton = [UIButton buttonWithType:UIButtonTypeCustom];

使用

self.rightButton = [UIButton buttonWithType:UIButtonTypeCustom];

应该可以。如果没有，请发布您如何声明该属性。

Answer 2

解决方案！

我的问题是我在 AppDelegate 中使用了以下代码：

UIViewController *controller = [[MyCustomController alloc] init];
[window addSubview:controller.view];
[controller release];

所以只有视图控制器的视图属性被保留，其他所有东西都被清除了。视图控制器没有任何功能（没有触摸事件，没有实例方法）。这就是 addTarget:action:forEvents: 不起作用的原因。

所以，聪明点 - 在 AppDelegate 的 dealloc 中释放您的视图控制器。 ;)

Answer 3

一个旧帖子，现在可能已全部排序，但还有另一个问题会导致崩溃：

[test addTarget:self action:@selector(testAction) forControlEvents:UIControlEventTouchUpInside]

不正确。 action:@selector(testAction) 必须有一个冒号，因此：

action:@selector(testAction:)

否则你会得到一个无法识别的选择器崩溃——这就是你得到的......