我尝试添加UITapGestureRecognizer
到imageview
如下图所示UITapGestureRecognizer称为立即
let gest=UITapGestureRecognizer(target: self, action: Selector(imgPressed()));
gest.delegate=self
thalaImg.addGestureRecognizer(gest)
这里是imgPressed
功能:
func imgPressed()
{
let alert=UIAlertController(title: "Img", message: "img pressed", preferredStyle: .Alert)
let okButton=UIAlertAction(title: "Ok", style: .Default, handler: nil)
alert.addAction(okButton)
presentViewController(alert, animated: true, completion: nil)
}
我加了3行代码中viewdidload
,添加了一个断点并运行了应用程序。我观察到的是,一旦编译器进入第一行,即let gest ...,即使在应用程序开始运行之前,它也会立即调用操作方法。显然window
尚未加载,它抛出下面的警告
Warning: Attempt to present on whose view is not in the window hierarchy!
我不明白为什么会这样。可有人请帮助我这个问题?
谢谢
“FUNC imgPressed() { 设警报= UIAlertController(标题: “图”,消息: “IMG按下”,preferredStyle:.Alert) 让okButton = UIAlertAction(标题: “OK”,样式:。默认情况下,处理程序:无) alert.addAction(okButton) presentViewController(警报,动画:真,完成:无) }” –
好吧删除()imgPressed method.And后双引号 “imgPressed”。 – Pushpa
你正在使用哪个swift版本意味着swift 2.0或swift 3.0吗? –