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我在 windows phone 8 中创建了一个应用程序，它可以从后台任务更改锁屏图像。通过代码运行时，该应用程序在模拟器和设备中运行良好。它包含launchforTest()，它使锁屏每30秒改变一次。

我收到一些评论，告诉我当应用程序通过商店上传时，launchforTest() 不起作用。它基本上是为了测试目的。

所以我的问题是，当我从商店安装我的应用程序进行 beta 测试时，后台任务不起作用，即锁屏图像不会改变

我在代码中缺少什么使其无法正常工作请帮忙。

这是我的代码

私有资源密集任务资源密集任务；私有字符串 resourceIntensiveTaskName = "SmartLockScreenScheduledTaskAgent"; private string resourceIntensiveTaskDescription = "显示最新交易。";

private StartTask()
{
    LockScreenChange("ms-appdata:///Local/Image0.jpg", true);
}

private async void LockScreenChange(string filePathOfTheImage, bool isAppResource)
{
    if (!LockScreenManager.IsProvidedByCurrentApplication)
    {
        // If you're not the provider, this call will prompt the user for permission.
        // Calling RequestAccessAsync from a background agent is not allowed.
        await LockScreenManager.RequestAccessAsync();
    }

    // Only do further work if the access is granted.
    if (LockScreenManager.IsProvidedByCurrentApplication)
    {
        // At this stage, the app is the active lock screen background provider.
        // The following code example shows the new URI schema.
        // ms-appdata points to the root of the local app data folder.
        // ms-appx points to the Local app install folder, to reference resources bundled in the XAP package
        // var schema = isAppResource ? "ms-appx:///" : "ms-appdata:///Local/";
        var uri = new Uri(filePathOfTheImage, UriKind.Absolute);

        // Set the lock screen background image.
        LockScreen.SetImageUri(uri);

        // Get the URI of the lock screen background image.
        var currentImage = LockScreen.GetImageUri();
        System.Diagnostics.Debug.WriteLine("The new lock screen background image is set to {0}", currentImage.ToString());
        UpdatePrimaryTile();
        StartResourceIntensiveAgent();// StartPeriodicAgent();//
        // MessageBox.Show("Lock screen changed. Click F12 or go to lock screen.");
    }
    else
    {
        MessageBox.Show("Background can't be updated as you clicked no!!");
    }
}

public void RemoveResourceIntensiveAgent()
{
    try
    {
        if (resourceIntensiveTask != null)
        {
            ScheduledActionService.Remove(resourceIntensiveTaskName);
        }
    }
    catch (Exception)
    {
    }
}

/// <summary>
/// Code to start the resource intensive task
/// </summary>
private void StartResourceIntensiveAgent()
{
    // Variable for tracking enabled status of background agents for this app.
    agentsAreEnabled = true;

    resourceIntensiveTask = ScheduledActionService.Find(resourceIntensiveTaskName) as ResourceIntensiveTask;

    // If the task already exists and background agents are enabled for the
    // application, you must remove the task and then add it again to update 
    // the schedule.
    if (resourceIntensiveTask != null)
    {
        ScheduledActionService.Remove(resourceIntensiveTaskName);
    }

    resourceIntensiveTask = new ResourceIntensiveTask(resourceIntensiveTaskName);

    // The description is required for periodic agents. This is the string that the user
    // will see in the background services Settings page on the device.
    resourceIntensiveTask.Description = (resourceIntensiveTaskDescription);

    // Place the call to Add in a try block in case the user has disabled agents.
    try
    {
        ScheduledActionService.Add(resourceIntensiveTask);
        //ResourceIntensiveStackPanel.DataContext = resourceIntensiveTask;
        resourceIntensiveTask.ExpirationTime = DateTime.Now.AddDays(14);
        // If debugging is enabled, use LaunchForTest to launch the agent in one minute.
        ScheduledActionService.LaunchForTest(resourceIntensiveTaskName, TimeSpan.FromSeconds(30));

    }
    catch (InvalidOperationException exception)
    {
        if (exception.Message.Contains("BNS Error: The action is disabled"))
        {
            MessageBox.Show("Background agents for this application have been disabled by the user.");
            agentsAreEnabled = false;
        }
    }
    catch (SchedulerServiceException)
    {
        // No user action required.
    }
}
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1 回答 1

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您的问题是您已将后台代理实现为ResourceIntensiveTask. ResourceIntensiveTasks 在以下非常具体的约束下运行：

  • 电话已插入
  • 锁定屏幕已启用
  • 无线网络（非蜂窝）连接可用

考虑将此后台代理实现为 PeriodicTask。如果您遇到运行时限制，请考虑重构尽可能多的代码，以便在主应用程序运行时尽可能多地预处理锁定屏幕图像的哪些部分，或者在包中创建可以使用的静态图像资源传达相同的信息。

参考： Windows Phone 后台代理：资源密集型代理的限制

于 2013-09-23T15:24:32.247 回答