如何在 WatchOS 上基于页面的界面中显示警报?

Question

我的手表应用程序有一个基于页面的界面，我真的不知道屏幕上当前是什么界面控制器(可能是 4 个中的 1 个(，但是无论应用程序在哪个屏幕上，我都需要弹出警报。 如果不一定知道哪个接口控制器是"当前"的，我如何显示警报？ 下面的代码仅在用户导航到此接口控制器时运行。 如果用户不在该页面上，则我在控制台中看到此错误2019-09-22 15:42:01.597663-0400 Watch Extension[501:526217] Warning: Attempt to present <PUICAlertSheetController: 0x18158c00> on <SPInterfaceViewController: 0x1795e800> whose view is not in the window hierarchy!

extension WorkoutControlsInterfaceController: WorkoutEndedDelegate {
func timerEndedCheckToSeeIfWorkoutEnded(_ manager: WorkoutManager) {
let endWorkoutAction = WKAlertAction(title: "End Workout", style: .default, handler: {
print("User has selected to end the workout")
self.workoutManager?.stopWorkout()
})
let cancelAction = WKAlertAction(title: "Cancel", style: .cancel, handler: {
})
self.becomeCurrentPage()
self.presentAlert(withTitle: "Workout Ended?", message: "It looks like your workout may have ended?", preferredStyle: .alert, actions: [endWorkoutAction, cancelAction])
}

}

Answer 1

可以使用共享WKExtesion对象中的visibileInterfaceController属性;

extension WorkoutControlsInterfaceController: WorkoutEndedDelegate {
func timerEndedCheckToSeeIfWorkoutEnded(_ manager: WorkoutManager) {
let endWorkoutAction = WKAlertAction(title: "End Workout", style: .default, handler: {
print("User has selected to end the workout")
self.workoutManager?.stopWorkout()
})
let cancelAction = WKAlertAction(title: "Cancel", style: .cancel, handler: {
})
WKExtension.shared().visibleInterfaceController?.presentAlert(withTitle: "Workout Ended?", message: "It looks like your workout may have ended?", preferredStyle: .alert, actions: [endWorkoutAction, cancelAction])
}

}