为什么 Carto Package Manager 在恢复后无法连接到它的数据库？

Question

我们正在使用 Carto Xamarin Mobile SDK 开发支持离线地图的应用程序。它工作正常，直到用户在处理后不尝试恢复应用程序。 Activity 创建（activity 使用 carto 包管理器）崩溃并出现异常：

Carto.PackageManager.CartoPackageManager.CartoPackageManager(string source, string dataFolder)<01980a2dae7148abb92e6b982667f448>:0
App.Droid.OfflineMaps.AndroidMapPackageManager.AndroidMapPackageManager()<76ae23b9271c407d865ebb6162639870>:0
App.Droid.Plugins.MapDownloader.Plugin.<>c.<Load>b__0_0()<76ae23b9271c407d865ebb6162639870>:0
MvvmCross.Platform.IoC.MvxSimpleIoCContainer.<>c__DisplayClass33_0<TInterface>.<RegisterSingleton>b__0()<4ddde23419c5494288c799fcdbb0f189>:0
MvvmCross.Platform.IoC.MvxSimpleIoCContainer.ConstructingSingletonResolver.Resolve()<4ddde23419c5494288c799fcdbb0f189>:0
MvvmCross.Platform.IoC.MvxSimpleIoCContainer.InternalTryResolve(Type type, MvxSimpleIoCContainer.IResolver resolver, ref object resolved
App.Core.ViewModels.Blocks.Maps.Offline.MapDownloaderOwnerViewModel.EnableMapDownloader(City city)<d6cca792b401420d922bc024

Here on line 105 you can see where exception is originally thrown.

在正常的进入页面中，它工作正常。 PackageManager 请求通过以下方式在页面 ViewModel 的构造函数中发生：

 Mvx.Resolve<MapDownloadsManager>(); // It receivs as injection platform-dependent packageManager

看来问题出在数据库路径上。我们正在生成文件夹名称，然后通过以下方式传递给 CartoPackageManager 构造函数：

 private static string CreateFolder(string folderPath)
        {

        var folder = GetDocumentDirectory(folderPath);

        if (!Directory.Exists(folder))
        {
            Directory.CreateDirectory(folder);
        }

        return folder;
    }

    private static string GetDocumentDirectory(string withFolder = null)
    {
        var documents = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

        return withFolder == null ? documents : Path.Combine(documents, withFolder + "/");
    }

您知道问题的根源在哪里吗？

P.S.: Carto SDK v 4.0.2, MvvmCross 4.4.0, 不幸的是现在不能更新到更新的.

经过一些研究，我发现任务队列已重置，现在假设该应用程序实际上在源代码中崩溃：

 std::string taskDbFileName = "tasks_v1.sqlite";
        try {
            _taskQueue = std::make_shared<PersistentTaskQueue>(createLocalFilePath(taskDbFileName));
        }
        catch (const std::exception& ex) {
            //This looks like: Error while constructing PackageManager: Package encryption keys do not match, trying to remove
            Log::Errorf("PackageManager: Error while constructing PackageManager::PersistentTaskQueue: %s, trying to remove...", ex.what());
            _taskQueue.reset();
            utf8_filesystem::unlink(taskDbFileName.c_str());
            try {
                _taskQueue = std::make_shared<PersistentTaskQueue>(createLocalFilePath(taskDbFileName));
            }
            catch (const std::exception& ex) {
                **throw FileException("Failed to create/open package manager task queue database", taskDbFileName); //App gets here.**
            }
        }

包管理器初始化：

 public class AndroidMapPackageManager : PackageManagerListener, IPackageManger
    {
        private readonly CartoPackageManager _packageManager;

        public AndroidMapPackageManager()
        {
            var folder = CreateFolder(OfflineMapStrings.MapsFolderName); // /data/user/0/com.app.cityguide/files/mapmap2/

 _packageManager =
                    new CartoPackageManager(OfflineMapsStrings.PackageManagerSource, folder)
                    {
                        PackageManagerListener = this
                    };
       }
}

我在其他 class 订阅侦听器事件后构造函数工作后立即启动它。而且，坦率地说，我从不阻止它。我需要它吗？

具有 FIllRam 的再生率为 100%。我使用了不允许背景的调试模式，现在我尝试了 Ram Filler，结果是一样的。

许可证问题：

05-25 12:41:41.091 26101 26101 E carto-mobile-sdk: CartoPackageManager: RegisterLicense not called, using random key for package encryption!
05-25 12:41:41.094 26101 26101 E carto-mobile-sdk: PackageManager: Error while constructing PackageManager: Package encryption keys do not match, trying to remove

Answer 1

问题是我在 SplashActivity 中注册了许可证密钥。但是，在恢复启动后 activity 没有显示，显然，没有执行许可证密钥的注册。我已将其移至自定义应用程序 class 并且有效：

public class CustomApplication : Application
{
        public override void OnCreate()
        {
            base.OnCreate();
            MapView.RegisterLicense(CartoApiKey, this);
        }
}

为什么 Carto Package Manager 在恢复后无法连接到它的数据库？

Why does Carto Package Manager can't connect to it's database after resuming?

filesystems

android

activity-lifecycle

mvvmcross

carto-mobile