Watchkit OS 2，WCSession在后台运行

Question

我有这个代码，当我在iPhone模拟器中打开应用程序并在ViewDidLoad中调用它时，它可以工作。但是如果我在应用委托中调用它，我就不能调用：

- (void)session:(nonnull WCSession *)session didReceiveApplicationContext:(nonnull NSDictionary<NSString *,id> *)applicationContext

在手表零件中

if ([WCSession isSupported]) {
        self.session = [WCSession defaultSession];
        self.session.delegate = self;
        [self.session activateSession];


       return YES;
}

但我希望它能在后台运行应用程序。我该怎么做呢？

我是iPhone的.delegate

    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
    {

        UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];

                    UIViewController *mainViewController = [storyboard instantiateInitialViewController];

                    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
                    self.window.rootViewController = mainViewController;
                    [self.window makeKeyAndVisible];

  if ([WCSession isSupported]) {
        self.session = [WCSession defaultSession];
        self.session.delegate = self;
        [self.session activateSession];

}
       return YES;

}

在ViewController中

-(void)senddata:(NSString *)data {

    WCSession* session = [WCSession defaultSession];


    NSDictionary *applicationDict = ///
    [session updateApplicationContext:applicationDict error:nil];
}

它是Extension中的.m

- (void)willActivate {
    // This method is called when watch view controller is about to be visible to user
    [super willActivate];

    if ([WCSession isSupported]) {
        self.session = [WCSession defaultSession];
        self.session.delegate = self;
        [self.session activateSession];



}

 [self.session updateApplicationContext:applicationDict error:nil];

Answer 1

在iOS端的视图控制器中激活WCSession不是一个好的选择，因为如果应用程序是在后台启动的，视图控制器将永远不会加载。你应该在你的应用代理的application:didFinishLaunchingWithOptions:方法中激活它。

- (BOOL)application:(UIApplication *)application
didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    //Any other code you might have

    if ([WCSession isSupported]) {
        self.session = [WCSession defaultSession];
        self.session.delegate = self;
        [self.session activateSession];
    }
}

在这里，我假设你已经将你的WCSessionDelegate方法移到了你的应用委托中。

然后，当您需要向手表发送任何类型的数据时，您可以检索默认会话并调用updateApplicationContext:error:等方法

WCSession* session = [WCSession defaultSession];
[session updateApplicationContext:applicationDict error:nil];