FileProvider “Failed to find configured root” exception

问题

One more of these FileProvider lost souls... I have been working on this problem more than a day now, and it seems I am missing something big. Any help would be appreciated!

I am trying to send email with attachment using FileProvider.

The part of my AndroidManifest.xml:

<provider
    android:name="android.support.v4.content.FileProvider"
    android:authorities="todolistj.todolist.fileprovider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/file_paths" />
</provider>

file_paths.xml:

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-files-path name="lists_to_send" path="export/"/>
</paths>

Creating the attachment:

String content = "hello world";
File file;
FileOutputStream outputStream;
try {
    File dir = context.getExternalFilesDir("export");
    if(!dir.exists()) dir.mkdir();
    file = new File(dir, "MyCache");
    if (file.exists ()) file.delete ();
    outputStream = new FileOutputStream(file);
    outputStream.write(content.getBytes());
    outputStream.close();
    return file.getAbsolutePath();
} catch (IOException e) {
    e.printStackTrace();
}

And the Uri creation:

    File readF = new File(fullFileName);
Uri uri = FileProvider.getUriForFile(this, "todolistj.todolist.fileprovider", readF);

where fullFileName is the value returned in the snippet for file creation.

On the Uri creation line I get exception:

...
Caused by: java.lang.IllegalArgumentException: Failed to find configured 
root that contains /storage/emulated/0/Android/data/todolistj.todolist/files/export/MyCache
...

As the documentation here (https://developer.android.com/reference/android/support/v4/content/FileProvider.html) states:

< external-files-path name="name" path="path" /> Represents files in the root of your app's external storage area. The root path of this subdirectory is the same as the value returned by Context#getExternalFilesDir(String) Context.getExternalFilesDir(null).

So external-files-path from my xml seems to match the context.getExternalFilesDir method I am using. Both places I have the "export" folder. Authorities seem to match... What could be my problem. I found no way to find and print FileProvider's "configured root"

回答1:

It seems I found workaround or fix. Changing the root directory type I was using from external-files-path to cache-path in the xml and from context.getExternalFilesDir("export"); to File dir = new File(context.getCacheDir(), "export"); for getting the folder to create the file.

And I successfully attached the file. Note that in the FileProvider.java for the FileProvider class I found the following code for constructing the Uris:

        if (TAG_ROOT_PATH.equals(tag)) {
            target = buildPath(DEVICE_ROOT, path);
        } else if (TAG_FILES_PATH.equals(tag)) {
            target = buildPath(context.getFilesDir(), path);
        } else if (TAG_CACHE_PATH.equals(tag)) {
            target = buildPath(context.getCacheDir(), path);
        } else if (TAG_EXTERNAL.equals(tag)) {
            target = buildPath(Environment.getExternalStorageDirectory(), path);
        }

Which looks like only the following 4 folders are supported: TAG_ROOT_PATH, TAG_FILES_PATH, TAG_CACHE_PATH, TAG_EXTERNAL. There is no TAG_EXTERNAL_FILES or something like this, so this seems like a mismatch between the documentation and the implementation, and actually the external-files-path matching the getExternalFilesDir method is not supported.

回答2:

File photoFile =new File(fullFileName);

        if (photoFile != null) {

            Uri photoURI =FileProvider.getUriForFile(MainActivity.this(your activity name),
                        BuildConfig.APPLICATION_ID + ".provider", photoFile);
}

if you create Uri like this may be it work for you.

回答3:

There is some workaound:

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <files-path name="logs" path="../logs/" />
    <!-- use ".." to get files from app's root data dir -->
</paths>

to provide files from /data/data/xxx.xxx.xxx/ in my case it was /data/data/xxx.xxx.xxx/logs/

来源：https://stackoverflow.com/questions/39293114/fileprovider-failed-to-find-configured-root-exception