Question

我的应用是基于地理定位的应用。我已经实现了在一些用户按“不允许位置服务”按钮再次引导他们进行设置以打开服务时弹出UIAlertview。

我面临的问题是，当用户最终打开按钮时，数据不会被加载到tableview，因为我的数据调用函数位于viewdidload和viewdidappear。有没有办法再次调用这些函数？

我做了类似下面的事情，它完全崩溃了我的应用程序：

extension ExploreViewController: CLLocationManagerDelegate {
func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {

    switch status {
    case .Denied:
        // Changed status to denied
        self.locationAlert = UIAlertView(title: "Location Services Permission Needed", message: "Location service needs to be turned on to use Peek! Please press setting button below and turn the service on!", delegate: self, cancelButtonTitle: "Settings")
        locationAlert.show()
        break
    case .AuthorizedWhenInUse:
        self.viewDidLoad()
        self.viewDidAppear(true)
        break
    default
        break
}

当我这样做的时候，在崩溃应用程序之前，它一直在调用viewdidload几百万次。任何建议表示赞赏

Answer 1

永远不要永远从不致电viewDidLoad或viewDidAppear（在后一种情况下，除了致电super）。它们是运行时发送给您的消息，用于报告视图控制器生命周期中的各个阶段。

Answer 2

只需将您的数据通话功能移到viewDidLoad和viewDidAppear之外：

而不是

override func viewDidLoad() {
    // do some stuff
}

写

override func viewDidLoad() {
    super.viewDidLoad()
    doSomeStuff()
}

func doSomeStuff() {
    // do some stuff
}

func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
    // do your current logic
    doSomeStuff()
}

Answer 3

func myCodeToRun() {
    //put all the code you want to run here
}

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)
    myCodeToRun()
}

extension ExploreViewController: CLLocationManagerDelegate {
func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {

switch status {
case .Denied:
    // Changed status to denied
    self.locationAlert = UIAlertView(title: "Location Services Permission Needed", message: "Location service needs to be turned on to use Peek! Please press setting button below and turn the service on!", delegate: self, cancelButtonTitle: "Settings")
    locationAlert.show()
    break
case .AuthorizedWhenInUse:
    myCodeToRun()
    break
default
    break

}

再次调用viewdidload和viewdid再次出现

3 个答案: