Question

在我的应用程序中，我想从设备上传pdf文件。所以我已经按照下面的链接

[Android: Browse and upload a PDF or word file in application from the device

通过使用此代码，选择pdf文件后获取空值。此 getFileNameByUri 方法返回 null vlaue。我不知道，野兔是什么问题。所以请建议我。在此先感谢...

这是我正在使用的代码......

private void getDocument()
        {
            Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
            intent.setType("application/pdf");
            intent.addCategory(Intent.CATEGORY_OPENABLE);
            // Only the system receives the ACTION_OPEN_DOCUMENT, so no need to test.
            startActivityForResult(intent, 1);
        }

这是反应性结果

  @Override
    protected void onActivityResult(int req, int result, Intent data)
    {
        // TODO Auto-generated method stub
        super.onActivityResult(req, result, data);
if (result == RESULT_OK)
        {
        Uri fileuri = data.getData();
        docFilePath = getFileNameByUri(this, fileuri);
}
}

这是文件路径的方法..

private String getFileNameByUri(Context context, Uri uri)
    {
        String filepath = "";//default fileName
        //Uri filePathUri = uri;
        File file;
        if (uri.getScheme().toString().compareTo("content") == 0)
        {
            Cursor cursor = context.getContentResolver().query(uri, new String[] { android.provider.MediaStore.Images.ImageColumns.DATA, MediaStore.Images.Media.ORIENTATION }, null, null, null);
            int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);

            cursor.moveToFirst();

            String mImagePath = cursor.getString(column_index);
            cursor.close();
            filepath = mImagePath;

        }
        else
            if (uri.getScheme().compareTo("file") == 0)
            {
                try
                {
                    file = new File(new URI(uri.toString()));
                    if (file.exists())
                        filepath = file.getAbsolutePath();

                }
                catch (URISyntaxException e)
                {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            else
            {
                filepath = uri.getPath();
            }
        return filepath;
    }

此方法 getFileNameByUri 返回空值..

Answer 1

这将从MediaProvider，DownloadsProvider和ExternalStorageProvider获取文件路径，同时回退到您提到的非官方ContentProvider方法。

/**
 * Get a file path from a Uri. This will get the the path for Storage Access
 * Framework Documents, as well as the _data field for the MediaStore and
 * other file-based ContentProviders.
 *
 * @param context The context.
 * @param uri The Uri to query.
 * @author paulburke
 */
public static String getPath(final Context context, final Uri uri) {

    final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

    // DocumentProvider
    if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
        // ExternalStorageProvider
        if (isExternalStorageDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            if ("primary".equalsIgnoreCase(type)) {
                return Environment.getExternalStorageDirectory() + "/" + split[1];
            }

            // TODO handle non-primary volumes
        }
        // DownloadsProvider
        else if (isDownloadsDocument(uri)) {

            final String id = DocumentsContract.getDocumentId(uri);
            final Uri contentUri = ContentUris.withAppendedId(
                    Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));

            return getDataColumn(context, contentUri, null, null);
        }
        // MediaProvider
        else if (isMediaDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            Uri contentUri = null;
            if ("image".equals(type)) {
                contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
            } else if ("video".equals(type)) {
                contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
            } else if ("audio".equals(type)) {
                contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
            }

            final String selection = "_id=?";
            final String[] selectionArgs = new String[] {
                    split[1]
            };

            return getDataColumn(context, contentUri, selection, selectionArgs);
        }
    }
    // MediaStore (and general)
    else if ("content".equalsIgnoreCase(uri.getScheme())) {
        return getDataColumn(context, uri, null, null);
    }
    // File
    else if ("file".equalsIgnoreCase(uri.getScheme())) {
        return uri.getPath();
    }

    return null;
}

/**
 * Get the value of the data column for this Uri. This is useful for
 * MediaStore Uris, and other file-based ContentProviders.
 *
 * @param context The context.
 * @param uri The Uri to query.
 * @param selection (Optional) Filter used in the query.
 * @param selectionArgs (Optional) Selection arguments used in the query.
 * @return The value of the _data column, which is typically a file path.
 */
public static String getDataColumn(Context context, Uri uri, String selection,
        String[] selectionArgs) {

    Cursor cursor = null;
    final String column = "_data";
    final String[] projection = {
            column
    };

    try {
        cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
                null);
        if (cursor != null && cursor.moveToFirst()) {
            final int column_index = cursor.getColumnIndexOrThrow(column);
            return cursor.getString(column_index);
        }
    } finally {
        if (cursor != null)
            cursor.close();
    }
    return null;
}


/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is ExternalStorageProvider.
 */
public static boolean isExternalStorageDocument(Uri uri) {
    return "com.android.externalstorage.documents".equals(uri.getAuthority());
}

/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is DownloadsProvider.
 */
public static boolean isDownloadsDocument(Uri uri) {
    return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}

/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is MediaProvider.
 */
public static boolean isMediaDocument(Uri uri) {
    return "com.android.providers.media.documents".equals(uri.getAuthority());
}

这些取自Paul Burke的回答

从设备内存上传pdf文件时获取空值

1 个答案: