ContentResolver - how to get file name from Uri

问题

I call startActivityForResult with Intent ACTION_GET_CONTENT. Some app returns me data with this Uri:

content://media/external/images/media/18122

I don't know if it is image or video or some custom content. How do I use ContentResolver to get the actual file name or content title from this Uri?

回答1:

You can get file name from this code, or any other field by modifying the projection

String[] projection = {MediaStore.MediaColumns.DATA};

ContentResolver cr = getApplicationContext().getContentResolver();
Cursor metaCursor = cr.query(uri, projection, null, null, null);
if (metaCursor != null) {
    try {
        if (metaCursor.moveToFirst()) {
            path = metaCursor.getString(0);
        }
    } finally {
        metaCursor.close();
    }
}
return path;

回答2:

@Durairaj's answer is specific to getting the path of a file. If what you're searching for is the file's actual name (since you should be using Content Resolution, at which point you'll probably get a lot of content:// URIs) you'll need to do the following:

(Code copied from Durairaj's answer and modified)

        String[] projection = {MediaStore.MediaColumns.DISPLAY_NAME};
        Cursor metaCursor = cr.query(uri, projection, null, null, null);
        if (metaCursor != null) {
            try {
                if (metaCursor.moveToFirst()) {
                    fileName = metaCursor.getString(0);
                }
            } finally {
                metaCursor.close();
            }
        }

The main piece to note here is that we're using MediaStore.MediaColumns.DISPLAY_NAME, which returns the actual name of the content. You might also try MediaStore.MediaColumns.TITLE, as I'm not sure what the difference is.

回答3:

To get filename, you can use new DocumentFile format.

DocumentFile documentFile = DocumentFile.fromSingleUri(this, data.getdata());
String fileName = documentFile.getName();

回答4:

For anyone using Kotlin who has the same problem, you can define an extension method to get the file name and size (in bytes) in one fell swoop. If it is unable to retrieve the fields, it returns null.

fun Uri.contentSchemeNameAndSize(): Pair<String, Int>? {
    return contentResolver.query(this, null, null, null, null)?.use { cursor ->
        if (!cursor.moveToFirst()) return@use null

        val name = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
        val size = cursor.getColumnIndex(OpenableColumns.SIZE)

        cursor.getString(name) to cursor.getInt(size)
    }
}

Use it thusly

val nameAndSize = yourUri.contentNameAndSize()
// once you've confirmed that is not null, you can then do
val (name, size) = nameAndSize

It might throw an exception, but it hasn't ever done so for me (as long as the URI is a valid content:// URI).

回答5:

private static String getRealPathFromURI(Context context, Uri contentUri)
{
    String[] proj = { MediaStore.Images.Media.DATA };
    CursorLoader loader = new CursorLoader(context, contentUri, proj, null, null, null);
    Cursor cursor = loader.loadInBackground();
    int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
    cursor.moveToFirst();
    String result = cursor.getString(column_index);
    cursor.close();
    return result;
}

回答6:

You can use the solution proposed by Durairaj with the following as the projection array:

String[] projection = { "_data" };

来源：https://stackoverflow.com/questions/13275007/contentresolver-how-to-get-file-name-from-uri

标签

android

android-contentresolver