UIInputViewController上的UIAlertView崩溃

Question

我正在使用Xcode6.0和swift。UIAlertView和UIAlertController (示例:以下两个函数)在从UIViewController继承的myViewController上工作得很好，但在从UIInputViewController继承的KeyboardViewController上崩溃。Apple不允许在自定义键盘上显示alertview吗?还是我的代码中有任何错误？欢迎并感谢您的回复。

func viewAlert() {
    var alertView = UIAlertView() <———
    alertView.addButtonWithTitle("Ok")
    alertView.title = "title"
    alertView.message = "message"
    alertView.show()
}    
func viewAlert0() {
    var alert = UIAlertController() <———
    alert.title = "title"
    alert.message = "are disabled in your device"
    alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.Default, handler: nil))
    self.presentViewController(alert, animated: true, completion: nil)
}

 <——— debugger error point:

0x325ca19:  calll  0x327e620                 ; symbol stub for: pthread_kill
0x325ca1e:  movl   $0x2710, (%esp)
0x325ca25:  calll  0x327ec50                 ; symbol stub for: usleep$NOCANCEL
0x325ca2a:  movl   $0xffffffe7, -0xc(%ebp)
0x325ca31:  movl   %esi, 0x4(%esp)
0x325ca35:  movl   $0x0, 0x8(%esp)
0x325ca3d:  movl   $0x3, (%esp)
0x325ca44:  calll  0x327e476                 ; symbol stub for: sigprocmask
0x325ca49:  ud2    <====== Thread 1 :EXC_BAD_INSTRUCTION(code=EXC_i386_INVOP,subcode=0x0)

Answer 1

从iOS 8开始，我们有了新的宏：

NS_EXTENSION_UNAVAILABLE_IOS

iOS不允许在EXTENSION中使用某些类

如果您正在构建CUSTOM KEYBOARD EXTENSION，则iOS不允许使用AlertView或AlertController

查看更多信息：

• https://developer.apple.com/library/ios/documentation/General/Conceptual/ExtensibilityPG/Keyboard.html
• https://developer.apple.com/library/ios/documentation/General/Conceptual/ExtensibilityPG/ExtensionCreation.html

Answer 2

希望它能帮助斯威夫特的某个人：

假设您有一个必须与iOS和扩展一起使用的库(在可能的情况下，我使用的UIApplication.sharedApplication().keyWindow对扩展不可用)

#if NS_EXTENSION_UNAVAILABLE_IOS


func captureScreen() -> UIImage {

    let window = UIApplication.sharedApplication().keyWindow
    let scale = UIScreen.mainScreen().scale

    UIGraphicsBeginImageContextWithOptions(window!.bounds.size, false, scale)

    window?.layer.renderInContext(UIGraphicsGetCurrentContext()!)
    let image : UIImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return image
}


#else
#endif

使用#ifdef允许我们为iOS和扩展编译这个文件。