存储访问框架-无法从uri获取文档树(从云端硬盘应用返回) [英] Storage Access Framework - failing to obtain document tree from uri (returned from Drive app)

问题描述

我的Android应用想要在Google云端硬盘中创建一个文件夹，并从设备上的云端硬盘应用中获取uri.

My Android app wants to create a folder in Google Drive and get the uri from the Drive app on the device.

它发送一个意图，您可以看到下面的代码:

It sends an intent, you can see the code below:

private void createFolder(String folderName) {
    Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
    intent.addCategory(Intent.CATEGORY_OPENABLE);
    // Create a file with the requested MIME type.
    intent.setType("vnd.android.document/directory");
    intent.putExtra(Intent.EXTRA_TITLE, folderName);
    startActivityForResult(intent, WRITE_REQUEST_CODE);
}

然后它获取返回的数据，您可以看到下面的代码:

then it gets the returned data, you can see the code below:

@Override
protected void  onActivityResult(int requestCode, int resultCode, Intent resultData)
{

    if (requestCode == WRITE_REQUEST_CODE && resultCode == Activity.RESULT_OK) {

        Uri uri = null;
       if (resultData != null) {
            uri = resultData.getData();
            Log.i("result", "Uri: " + uri.toString());
            DocumentFile pickedDir = DocumentFile.fromTreeUri(this, uri); //this line gives the error
                       }
    }

}

我使用了在互联网上发现的一种模仿类型，它似乎是一种标准类型.使用"application/vnd.google-apps.folder"时会发出相同的错误. 目标是要有一个文档树，但是在logcat中，出现以下错误:

I used a mimetype found on the internet that seems to be a standard type. The same error is issued when using "application/vnd.google-apps.folder". The goal is to have a document tree but in logcat I get the following error:

java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=43, result=-1, data=Intent { dat=content://com.google.android.apps.docs.storage/document/acc=1;doc=encoded=LongStringWithRandomCharactersHere/j flg=0x43 }} to activity {com.example.myapplication/com.example.myapplication.MainActivity}: java.lang.IllegalArgumentException: Invalid URI: content://com.google.android.apps.docs.storage/document/acc%3D1%3Bdoc%3Dencoded%3DSameLongStringWithRandomCharactersHere%2Fj

及以下

Caused by: java.lang.IllegalArgumentException: Invalid URI: content://com.google.android.apps.docs.storage/document/acc%3D1%3Bdoc%3Dencoded%3DAnotherLongStringWithDifferentRandomDataHere

这是完整的堆栈跟踪:

2019-05-31 15:06:50.167 31184-31184/com.example.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myapplication, PID: 31184
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=43, result=-1, data=Intent { dat=content://com.google.android.apps.docs.storage/document/acc=1;doc=encoded=randomcharacters flg=0x43 }} to activity {com.example.myapplication/com.example.myapplication.MainActivity}: java.lang.IllegalArgumentException: Invalid URI: content://com.google.android.apps.docs.storage/document/acc%3D1%3Bdoc%3Dencoded%3Drandomcharacters
    at android.app.ActivityThread.deliverResults(ActivityThread.java:4365)
    at android.app.ActivityThread.handleSendResult(ActivityThread.java:4409)
    at android.app.ActivityThread.-wrap19(Unknown Source:0)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1670)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6687)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:810)
 Caused by: java.lang.IllegalArgumentException: Invalid URI: content://com.google.android.apps.docs.storage/document/acc%3D1%3Bdoc%3Dencoded%3Drandomcharacters
    at android.provider.DocumentsContract.getTreeDocumentId(DocumentsContract.java:1023)
    at android.support.v4.provider.DocumentFile.fromTreeUri(DocumentFile.java:138)
    at com.example.myapplication.MainActivity.onActivityResult(MainActivity.java:254)
    at android.app.Activity.dispatchActivityResult(Activity.java:7295)
    at android.app.ActivityThread.deliverResults(ActivityThread.java:4361)
    at android.app.ActivityThread.handleSendResult(ActivityThread.java:4409) 
    at android.app.ActivityThread.-wrap19(Unknown Source:0) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1670) 
    at android.os.Handler.dispatchMessage(Handler.java:106) 
    at android.os.Looper.loop(Looper.java:164) 
    at android.app.ActivityThread.main(ActivityThread.java:6687) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:810) 

uri没错，因为我可以进一步提取在云端硬盘上成功创建的文件夹的名称(大小为= 0). 怎么了?看来我的应用无法将其作为文档树来处理.

The uri is not wrong because I can further extract the name of the folder (and the size=0), that is successfully created on the Drive cloud. What's wrong instead? It seems that my app cannot handle it as a document tree.

推荐答案

这正在使用Google云端硬盘云空间，但可能是黑客.不能保证始终工作.

This is working with Google Drive cloud space but maybe it's a hack. It is not guaranteed to always work.

此示例在用户创建的云文件夹中创建一个云文件(SAF选择器由应用程序打开).

This example creates a cloud file in a cloud folder that was created by the user (the SAF picker is opened by the app).

创建云文件夹(用户必须首先从选择器UI中选择云根)

Creating the cloud folder (the user has to select the cloud root first from the picker UI)

 Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
 intent.setType("vnd.android.document/directory");
 intent.addFlags(Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION);
 intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
 startActivityForResult(intent, CREATE_DIRECTORY_REQUEST_CODE);

onActivityResult

onActivityResult

@Override
protected void onActivityResult(int requestCode,int resultCode, Intent data) 
{
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == CREATE_DIRECTORY_REQUEST_CODE) 
    {
      if (resultCode == Activity.RESULT_OK) {
      int takeFlags = data.getFlags()
                   &
      (Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
      ContentResolver resolver = this.getContentResolver();
      resolver.takePersistableUriPermission(data.getData(),takeFlags);
      archiveUri(data.getData().toString()); //important to save the toString() result, not getPath()
      archiveAuthority(data.getData().getAuthority());
      } 
      else 
      {
            // The user cancelled the request.
      }
    }
}

下次使用Uri

ContentResolver contentResolver;
contentResolver = this.getContentResolver();
uriPath=retrieveArchivedUri();
Uri tempUri;
Uri uri; 
String authority;
tempUri=Uri.parse(uriPath);
authority=retrieveArchivedAuthority();
uri= DocumentsContract.buildDocumentUri(authority,
            DocumentsContract.getDocumentId(tempUri)); //folder Uri

try 
{
 DocumentsContract.createDocument(contentResolver,uri,"plain/text","fileName");
} 
catch (FileNotFoundException e) 
{
        e.printStackTrace();
}

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