ios - BGTaskScheduler 提交调用失败，BGTaskSchedulerErrorDomain 代码为 : 1

Question

BGTaskScheduler 因“BGTaskSchedulerErrorDomain”而失败 - 代码:iOS 13.0 上的 1

我已经尝试过 Apple 提供的示例程序 ColorFeed，它面临同样的问题

let request = BGProcessingTaskRequest(identifier: "com.example.apple-samplecode.ColorFeed.db_cleaning")
request.requiresNetworkConnectivity = false
request.requiresExternalPower = true

do 
{
  try BGTaskScheduler.shared.submit(request)
} catch {
  print("Could not schedule database cleaning: \(error)")
}

上面的代码在 applicationDidEnterBackground 中被调用

早些时候任务在 didFinishLaunchingWithOptions 中注册 ...

 BGTaskScheduler.shared.register(forTaskWithIdentifier: "com.example.apple-samplecode.ColorFeed.db_cleaning", using: nil) { task in

        // Downcast the parameter to a processing task as this identifier is used for a processing request.
        self.handleDatabaseCleaning(task: task as! BGProcessingTask)

 }

Answer 1

代码1表示BGTaskScheduler.Error.unavailable

根据文档:

This error usually occurs for one of three reasons:

• The user has disabled background refresh in settings.
• The app is running on Simulator which doesn’t support background processing.
• The extension either hasn’t set RequestsOpenAccess to YES in The Info.plist File, or the user hasn’t granted open access.

您是在真实设备上运行吗？该设备是否启用了后台刷新？