ios5 - 单击按钮时出现“EXC_BAD_ACCESS”

Question

I am a total beginner to Objective C.

Currently I try to display a view in my main window. This view contains a button. For some reason by clicking this button xcode throws an error.

Hopefully you can help me to understand what I am doing wrong.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];

    BtnView *btn = [[BtnView alloc] init];
    [self.window addSubview:btn.view];        
    [self.window makeKeyAndVisible];

    return YES;
}

The viewController of my button view has an action for recognizing a touch up event h file:

- (IBAction)touched:(id)sender;

and in the m file

- (IBAction)touched:(id)sender {
    //actions ...
}

By touching the button I get the following error:

Whats wrong?

m file:

h file:

Answer 1

I assume you have ARC enabled for this project.

When you return from didFinishLaunchingWithOptions: the object assigned to btn will be released since you assign it to a local variable that is only defined within that method. Make BtnView *btn a strong property of your class and it should stay around to handle the button presses. (Remember to use self.btn in references to it.)

(But, I'm curious, why not just put the button on your main view in the first place and then not worry about an extra controller and subviews?)

Answer 2

- (IBAction)touched

尝试不使用发件人

Answer 3

In .xib file, you can hook up the button to file's owner.

1) Right Click on button. Then one window will be appeared. You can see Touch Up Inside in that window and click on small circle and drag to file's owner and connect to touched . I think it will be helpful to you.

Answer 4

Is there any specific reason why do you need the whole UIViewController to be a button? The conventional way to do this would be to have the UIViewController as a controller and than put a UIButton as a subview to its view in the viewDidLoad method, hook it up to the desired methods and even have it across the whole screen if you need. In case you need to customize the appearance, you can do that with UIButton too.