Question

我想使用按钮更改为不同的视图，但我必须点按两次按钮才能使其动作。

为什么我必须点击两次？

以下是代码：

func tapEmergencyKitsDetected(sender:AnyObject) {
        myStack.push(thisNC)
        let storyboard : UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        let vc : UIViewController = storyboard.instantiateViewControllerWithIdentifier("NCEmergencyKitsIntro") as! UIViewController
        self.presentViewController(vc, animated: true, completion: nil)
}

func tapEmergencyPlanDetected(sender:AnyObject) {

    myStack.push(thisNC)
    let storyboard : UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
    let vc : UIViewController = storyboard.instantiateViewControllerWithIdentifier("NCEmergencyPlanList") as! UIViewController
    self.presentViewController(vc, animated: true, completion: nil)
}

@IBAction func tapEmergencyKits(sender: UIButton) {
    self.buttonEmergencyKits.addTarget(self, action: Selector("tapEmergencyKitsDetected:"), forControlEvents: UIControlEvents.TouchDown)
}

@IBAction func tapEmergencyPlan(sender: UIButton) {
    self.buttonEmergencyKits.addTarget(self, action: Selector("tapEmergencyPlanDetected:"), forControlEvents: UIControlEvents.TouchDown)
}

Answer 1

按钮确实响应第一次点击。它正是你告诉它做的。但那件事并没有任何可见结果。当你说：

@IBAction func tapEmergencyKits(sender: UIButton) {
    self.buttonEmergencyKits.addTarget(
        self, action: Selector("tapEmergencyKitsDetected:"), 
        forControlEvents: UIControlEvents.TouchDown)
}

您所做的就是重新配置按钮self.buttonEmergencyKits将在下一步点击时执行的操作。事实上，在它的下一次拍打中，它就是它。

为什么我必须在我的应用中点按两次按钮？

1 个答案: