向后兼容解决方案:

SEL requestSelector = NSSelectorFromString(@"requestWhenInUseAuthorization");
if ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusNotDetermined &&
    [self.locationManager respondsToSelector:requestSelector]) {
    [self.locationManager performSelector:requestSelector withObject:NULL];
} else {
    [self.locationManager startUpdatingLocation];
}

在Info.plist中设置NSLocationWhenInUseUsageDescription键

我最终解决了自己的问题。

显然，在iOS 8 SDK中，在开始位置更新之前需要调用CLLocationManager上的requestAlwaysAuthorization(用于后台位置)或requestWhenInUseAuthorization(仅用于前台位置)。

在Info中还需要NSLocationAlwaysUsageDescription或NSLocationWhenInUseUsageDescription键。Plist并在提示符中显示一条消息。加上这些就解决了我的问题。

更多详细信息，请查看:Core-Location-Manager-Changes-in-ios-8

解决方案与向后兼容，不产生Xcode警告:

SEL requestSelector = NSSelectorFromString(@"requestWhenInUseAuthorization");
if ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusNotDetermined &&
  [self.locationManager respondsToSelector:requestSelector]) {
((void (*)(id, SEL))[self.locationManager methodForSelector:requestSelector])(self.locationManager, requestSelector);
  [self.locationManager startUpdatingLocation];
} else {
  [self.locationManager startUpdatingLocation];
}

在Info.plist中设置NSLocationWhenInUseUsageDescription键。

对于iOS版本11.0+: 在Info.plist中设置NSLocationAlwaysAndWhenInUseUsageDescription键。还有另外2把钥匙。

在iOS 8中，你需要做两件额外的事情来让定位工作:给你的信息添加一个键。Plist并从位置管理器请求授权，要求它启动

info.plist:

<key>NSLocationUsageDescription</key>
<string>I need location</string>
<key>NSLocationAlwaysUsageDescription</key>
<string>I need location</string>
<key>NSLocationWhenInUseUsageDescription</key>
<string>I need location</string>

将此添加到代码中

if (IS_OS_8_OR_LATER)
{
    [locationmanager requestWhenInUseAuthorization];

    [locationmanager requestAlwaysAuthorization];
}

在[locationManager startUpdatingLocation];之前，添加一个iOS8位置服务请求:

if([locationManager respondsToSelector:@selector(requestAlwaysAuthorization)])
    [locationManager requestAlwaysAuthorization];

编辑应用程序的信息。并添加键NSLocationAlwaysUsageDescription与字符串值，将显示给用户(例如，我们尽我们最大的努力来保持您的电池寿命。)

如果你的应用程序只在应用程序打开时需要位置服务，请替换:

requestAlwaysAuthorization with requestWhenInUseAuthorization和

NSLocationAlwaysUsageDescription和NSLocationWhenInUseUsageDescription。

为了访问用户在iOS中的位置。您需要添加两个键

NSLocationWhenInUseUsageDescription

NSLocationAlwaysUsageDescription

进入信息。plist文件。

    <key>NSLocationWhenInUseUsageDescription</key>
    <string>Because I want to know where you are!</string>
    <key>NSLocationAlwaysUsageDescription</key>
    <string>Want to know where you are!</string>

请看下图。