ios - iPhone GPS导航不会退出

Question

我有一个 iPhone 应用程序，其中一个 View 上有一个导航按钮。当用户单击此按钮时，它会使用手机 CLLocationManager 打开 iPhone 的 GPS 应用程序。然后，它获取用户当前位置并显示到预定义设置点的导航。

这里一切正常，但是当我退出 GPS 导航(通过单击手机主页按钮)并返回应用程序时，应用程序会显示带有导航按钮的 View 一两秒，然后无需点击任何按钮即可再次启动 GPS 导航。我也无法单击此处的任何按钮，例如顶部导航栏中的后退按钮。

谁能告诉我为什么会发生这种情况以及如何阻止它？这是我的 GPS 导航代码。

在我的 viewDidLoad 中，我以编程方式创建了导航按钮

UIButton *mapButton = [[UIButton alloc] init];
mapButton = [UIButton buttonWithType:UIButtonTypeCustom];
mapButton.tag = 1;
mapButton.frame = CGRectMake(20, 430, 280.f, 40.f);
UIImage *mapButtonImage = [UIImage imageNamed:@"gettingHereMapButton.png"];
[mapButton setBackgroundImage:mapButtonImage forState:UIControlStateNormal];
[self.view addSubview:mapButton];
[mapButton addTarget:self action:@selector(mapButtonClicked) forControlEvents:UIControlEventTouchUpInside];

然后进入

- (void) mapButtonClicked
{
    self.locationManager = [[CLLocationManager alloc] init];
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;
    locationManager.delegate = self;
    [locationManager startUpdatingLocation];
}

- (void) locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
    UIAlertView *alert =
    [[UIAlertView alloc] initWithTitle:@"Alert"
                           message:@"An error has occured. Please try again later."
                          delegate:self
                 cancelButtonTitle:@"Cancel"
                 otherButtonTitles:@"OK",
                 nil]; 
    [alert show];
}

- (void) locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
    CLLocation *newLocation = [locations lastObject];
    CLLocation *oldLocation;

    NSString *destAddress = @"52.269444, -9.708674";
    NSString *url = [NSString stringWithFormat: @"http://maps.apple.com/maps?saddr=%f%f&daddr=%@",
                 newLocation.coordinate.latitude,
                 newLocation.coordinate.longitude,
                 [destAddress stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:url]];
}

我需要向此 View 添加什么才能阻止这种情况发生？

Answer 1

问题是，当您执行[locationManager startUpdatingLocation];时，locationManager会多次调用didUpdateLocations。

要修复它，请在

- (void) locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations

添加这一行:

[manager stopUpdatingLocation];

就在上面:

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:url]];