ContentResolver - 如何从 Uri 获取文件名

Question

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?

Answer 1

@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.

Answer 2

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;

Answer 3

To get filename, you can use new DocumentFile format.

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

Answer 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).

Answer 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;
}

Answer 6

The accepted answer is not complete. There are more checks missed out.

Here is what I have arrived at after a read of all the answers presented here as well what some Airgram has done in their SDKs - A utility that I have open sourced on Github:

https://github.com/mankum93/UriUtilsAndroid/tree/master/app/src/main/java/com/androiduriutils

Usage

As simple as calling, UriUtils.getDisplayNameSize() . It provides both the name and size of the content.

Note: Only works with a content:// Uri

Here is a glimpse on the code:

/**
 * References:
 * - https://www.programcreek.com/java-api-examples/?code=MLNO/airgram/airgram-master/TMessagesProj/src/main/java/ir/hamzad/telegram/MediaController.java
 * - https://stackoverflow.com/questions/5568874/how-to-extract-the-file-name-from-uri-returned-from-intent-action-get-content
 *
 * @author Manish@bit.ly/2HjxA0C
 * Created on: 03-07-2020
 */
public final class UriUtils {


    public static final int CONTENT_SIZE_INVALID = -1;

    /**
     * @param context context
     * @param contentUri content Uri, i.e, of the scheme <code>content://</code>
     * @return The Display name and size for content. In case of non-determination, display name
     * would be null and content size would be {@link #CONTENT_SIZE_INVALID}
     */
    @NonNull
    public static DisplayNameAndSize getDisplayNameSize(@NonNull Context context, @NonNull Uri contentUri){

        final String scheme = contentUri.getScheme();
        if(scheme == null || !scheme.equals(ContentResolver.SCHEME_CONTENT)){
            throw new RuntimeException("Only scheme content:// is accepted");
        }

        final DisplayNameAndSize displayNameAndSize = new DisplayNameAndSize();
        displayNameAndSize.size = CONTENT_SIZE_INVALID;

        String[] projection = new String[]{MediaStore.Images.Media.DATA, OpenableColumns.DISPLAY_NAME, OpenableColumns.SIZE};
        Cursor cursor = context.getContentResolver().query(contentUri, projection, null, null, null);
        try {
            if (cursor != null && cursor.moveToFirst()) {

                // Try extracting content size

                int sizeIndex = cursor.getColumnIndex(OpenableColumns.SIZE);
                if (sizeIndex != -1) {
                    displayNameAndSize.size = cursor.getLong(sizeIndex);
                }

                // Try extracting display name
                String name = null;

                // Strategy: The column name is NOT guaranteed to be indexed by DISPLAY_NAME
                // so, we try two methods
                int nameIndex = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
                if (nameIndex != -1) {
                    name = cursor.getString(nameIndex);
                }

                if (nameIndex == -1 || name == null) {
                    nameIndex = cursor.getColumnIndex(MediaStore.Images.Media.DATA);
                    if (nameIndex != -1) {
                        name = cursor.getString(nameIndex);
                    }
                }
                displayNameAndSize.displayName = name;
            }
        }
        finally {
            if(cursor != null){
                cursor.close();
            }
        }

        // We tried querying the ContentResolver...didn't work out
        // Try extracting the last path segment
        if(displayNameAndSize.displayName == null){
            displayNameAndSize.displayName = contentUri.getLastPathSegment();
        }

        return displayNameAndSize;
    }
}

Answer 7

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

String[] projection = { "_data" };