在共享存储 Xamarin 表单中保存文件 [英] Saving a file in shared storage Xamarin forms

问题描述

我需要在android的共享存储中保存一个文件.我遇到了这个链接 =>

解决方案

在您的 Android 项目中使用它来将流保存到文件:

public async Task SaveAndView(string fileName, String contentType, MemoryStream stream){尝试{字符串根=空；//获取android设备的根路径.如果(Android.OS.Environment.IsExternalStorageEmulated){root = Android.OS.Environment.ExternalStorageDirectory.ToString();}别的root = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);//创建目录和文件Java.IO.File myDir = new Java.IO.File(root + "/meusarquivos");myDir.Mkdir();Java.IO.File file = new Java.IO.File(myDir, fileName);//如果文件存在则删除if (file.Exists()) file.Delete();//将流写入文件FileOutputStream outs = new FileOutputStream(file);outs.Write(stream.ToArray());outs.Flush();关闭()；}捕获(异常前){PostLog.AppCenterLogExcecao(ex, new Dictionary { { "origem", "OrderViewModel - 159" } });}}

在您的共享代码中:

await DependencyService.Get().SaveAndView(OrderId.ToString() + .pdf", application/pdf", stream);

请务必在使用代码前询问权限.

I need to save a file in the shared storage of android. I came across this link => https://developer.android.com/training/data-storage/shared/documents-files

I am using the dependency service and I am able to successfully save a file to desired location. But I am able to create only a blank file. I need to write some content into that file. Actually I created a thread few hours ago with android tag and got the solution where I had to override the OnActivityResult method and get the intent data. Now I have done it and I am able to get the intent data. But Now I dont know which path should i choose from the intent and how to open the file using the chosen path and how to write content into that chosen file. Any android + xamarin expert should be able to help me..

The android platform code to implement the write service:

Activity _activity;
private static int CREATE_FILE = 6835;

public WriteFileService()
{
    _activity = CrossCurrentActivity.Current.Activity;
}

void IWriteService.WriteFile(string Content)
{
    Intent intent = new Intent(Intent.ActionCreateDocument);
    intent.AddCategory(Intent.CategoryOpenable);
    intent.SetType("application/txt");
    intent.PutExtra(Intent.ExtraTitle, "Invoice.txt");
    _activity.StartActivityForResult(intent, CREATE_FILE);
}

The overriden OnActivityResultMethod:

protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
    Toast.MakeText(Application.Context, "requestCode is " + requestCode, ToastLength.Short).Show();
    if (requestCode == 6835)
    {
        if (data != null)
        {
            Toast.MakeText(Application.Context,
                data.GetType().ToString(),
                ToastLength.Short).Show();

        }
    }

    base.OnActivityResult(requestCode, resultCode, data);
}

This is the screen of the Intent Data from OnActivityResult

解决方案

Use this in your Android project to save a stream to file:

public async Task SaveAndView(string fileName, String contentType, MemoryStream stream)
        {
            try
            {
                string root = null;
                //Get the root path in android device.
                if (Android.OS.Environment.IsExternalStorageEmulated)
                {
                    root = Android.OS.Environment.ExternalStorageDirectory.ToString();
                }
                else
                    root = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);

                //Create directory and file 
                Java.IO.File myDir = new Java.IO.File(root + "/meusarquivos");
                myDir.Mkdir();

                Java.IO.File file = new Java.IO.File(myDir, fileName);

                //Remove if the file exists
                if (file.Exists()) file.Delete();

                //Write the stream into the file
                FileOutputStream outs = new FileOutputStream(file);
                outs.Write(stream.ToArray());

                outs.Flush();
                outs.Close();
           }
            catch (Exception ex)
            {
                PostLog.AppCenterLogExcecao(ex, new Dictionary<string, string> { { "origem", "OrderViewModel - 159" } });
            }
        }

And in your shared code:

await DependencyService.Get<ISave>().SaveAndView(OrderId.ToString() + ".pdf", "application/pdf", stream);

Be sure to ask for the permissions before using the code.

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