iPhone Tap Counter

Question

我正在尝试通过Xcode和Interface Builder获取UI按钮与UI标签进行交互。我应该在此代码中更改哪些内容？ （我已经在Interface Builder中链接了所有内容。当我按下按钮时应用程序崩溃了。）

@synthesize window;
@synthesize label;
@synthesize anotherLabel;
@synthesize myButton;


    #pragma mark -
    #pragma mark Application lifecycle



    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

     [myButton setTitle:@"Press Here" forState:UIControlStateNormal];

     window.backgroundColor = [UIColor grayColor];

     label.text = [[NSDate date] description];


        // Override point for customization after application launch.

     [myButton addTarget:anotherLabel action:@selector(doButton:) forControlEvents:UIControlEventTouchUpInside];

        [window makeKeyAndVisible];

     return YES;
    }

     -(void) doButton:(UILabel *)anotherLabel{
     static int count;
        count++;

            }

Answer 1

好的，首先，你没有这样更新标签，因为只是将另一个标签作为参数传递，这并不意味着它会改变它的属性。另外，您没有为doButton传递正确的参数：在这种情况下，我会忘记一个参数，并通过说：

来更新另一个标签

static int count;
count++;
NSString *countString = [NSString stringWithFormat:@"%d", count];
[anotherLabel setText: countString];