Question

我有一个从服务器下载并保存的pdf。接下来，我在UIWebView内的文件路径中打开文件。这是我第一次启动应用程序时的工作原理。当我再次重新启动应用程序时，即使文件路径相同，文档也不会打开。此外，该文档确实存在于应用程序的文档文件夹中。

我正在做类似的事情： -

SaveToFolder.cs

var filePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), fileName);

using (FileStream destinationStream = File.Create(filePath))
{
     await documentStream.CopyToAsync(destinationStream);
}

第一次保存文档后的文件路径： -

 /var/mobile/Containers/Data/Application/C3EA2325-81CA-4EC9-8C03-479ACF7EE330/Documents/Insufficiency.pdf

应用重启的文件路径

/var/mobile/Containers/Data/Application/C3EA2325-81CA-4EC9-8C03-479ACF7EE330/Documents/Insufficiency.pdf

我做错了吗？

Answer 1

我在iOS中创建了一个用于阅读和阅读的文件。写文件。请查看iOS

using System;
using Xamarin.Forms;
using FileReader.iOS;
using System.IO;
using FileReader;
using Foundation;
using System.Linq;
using System.Threading.Tasks;

[assembly: Dependency(typeof(SaveAndLoadiOS))]

namespace FileReader.iOS
{
    public class SaveAndLoadiOS : LoadAndSave
    {
        public static string DocumentPath
        {
            get
            {
                var documentURL = NSFileManager.DefaultManager.GetUrls(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomain.User).Last();
                return documentURL.Path;
            }
        }

        public string CreatePath(string fileName)
        {
            return Path.Combine(DocumentPath, fileName);
        }

        public async Task SaveTextAsync(string fileName, string text)
        {
            string path = CreatePath(fileName);
            if (IsFileExits(fileName))
            {
                File.Delete(path);
            }
            using (StreamWriter sw = File.CreateText(path))
                await sw.WriteAsync(text);  
        }

        public async Task<string>  LaodTextAsync(string fileName)
        {
            string path = CreatePath(fileName);
            using (StreamReader sr = File.OpenText(path))
                return await sr.ReadToEndAsync();
        }

        public bool IsFileExits(string fileName)
        {
            return File.Exists (CreatePath(fileName));
        }
    }
}

从我的.CS类（ContentPage的子类）读取，下面是代码

var tempFileService =  DependencyService.Get<LoadAndSave>();
var itemFile = await tempFileService.LaodTextAsync(tempFile.StoredFileName);
var rootobject = JsonConvert.DeserializeObject<Rootobject>(itemFile);

其中LoadAndSave是如下界面

using System;
using System.Threading.Tasks;

namespace FileReader
{
    public interface LoadAndSave
    {
        Task SaveTextAsync(string fileName, string text);
        Task<string> LaodTextAsync(string fileName);
        bool IsFileExits(string fileName);
    }
}

希望它有所帮助。

Answer 2

我刚才遇到了同样的问题。您可以参考Can't find saved file (in device) after restarting the app

根据答案

You shouldn't store raw file paths for persistence (or if you do, know that the root can move on you). A better practice would be to only store the relative part of the path and always attach it to the current "root" path in question (particularly if you might be sharing data across devices as with iCloud).

也许你的根也在改变。您可以更改您的方法，并使用Xamarin中的文档文件夹的默认路径附加文件名： -

var docsPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments); filePath = docsPath +"/" + "Insuffeciency.pdf";

另外，请考虑在保存文件时将Personal文件夹更改为MyDocuments文件夹。

PDF没有从App重新启动iOS上的文档文件夹加载

2 个答案: