Rdex for Android

Rdex for Android Screenshot

Rdex is available for Android devices. If you use Rdex in conjunction with a cloud storage service such as Dropbox you can maintain synchronization between Rdex for Windows and Android.

Install Rdex 2.4.18 for Android—released Oct 2020

Get it on Google Play

Download Rdex 2.4.18 for Android
Here's the apk for those who want to install it manually:
Rdex-2-4-18.apk, 96,957 bytes
md5 hash: 5e79cb6af038c99e4cc42f704d946e83

Opening Files

The easiest way to transfer files between PC and Android is by using a cloud-based storage app such as Dropbox. Just open an Rdex cardfile (.rdx) using Dropbox. The file will be downloaded to your Android device and Dropbox will offer a selection of apps that can open it. Choose Rdex. Any changes you make will automatically be synchronized. When you are finished be sure to press the Android 'Back' button until you return to the Dropox screen and always access a fresh copy of the file from Dropbox each time you use it. This will ensure the cardfile remains synchronized if you also modify it with another computer or device.

New security restrictions were introduced in Android 7. Dropbox can still open a .rdx file but Google Drive and MS OneDrive cannot. They can only open well-known file types. If you change the file extension from .rdx to .txt using a file browser Google Drive and MS OneDrive will offer Rdex as one of the apps that can open the file.

Android security now restricts Rdex to only access files within the folder Android/data/com.pnewman.rdex/files. In Android 11 all access to the Android/data folder is blocked, even to file manager apps. The easiest way to move an Rdex file into Android/data/com.pnewman.rdex/files is to connect the device up to a computer via a USB cable and manage the files from there. Alternatively there is an internal system file manager app that is permitted to manage files inside the "Android/data" folder: the AOSP Files app. Detailed instructions for using it can be found here.

To open a file from within Rdex, press the menu button and select "File/Open File." Android security restricts Rdex to files within the folder Android/data/com.pnewman.rdex. Select a file by touching it. Rdex also has a menu option to open recently used files. Rdex will attempt to load the most recently used file when it starts up.

You can find out which file Rdex is using from the "About Rdex" menu item. (By default files are stored in the Android/data/com.pnewman.rdex/files folder.) You can copy the file, rename it, upload it or move it using a file browser but Rdex can only open it from within its own file space. File/Save As can be used to save a plain text backup copy of the file.

Rdex Android supports all Rdex file formats: ASCII, UTF-8, and AES-128 encrypted format. See the file formats page for a description of file formats.

Brief Instructions

To create a new card or edit an existing card, access the edit submenu with Menu/Edit and select "New Card" or "Edit Card." Type in the text you want or use copy and paste. When you are done press the "Save" button. You can delete a card from the edit submenu using "Delete Card." A new cardfile can be created from the edit submenu using "Create New Database." The cardfile is always saved after any changes.

To prevent any accidental changes to the database you can select "Read Only Mode" in Menu/Preferences. The edit menu is disabled in Read Only Mode.

To find a card, type a string in the Search Box and tap the search icon. Search strings are not case sensitive. Tap the search icon again to find the next occurrence. If the Search Box is blank, you simply jump to the next card. If you type a string into the Search Box and tap "Enter" or "Done" on the keyboard, Rdex will list the first line of every card that contains the search string. The list icon at the top left of the main screen will list the first line of every card. Select the desired card by tapping it.

To copy an email address or web link to the clipboard simply tap it. It will be highlighted showing exactly what was copied to the clipboard. You can then switch to another app and paste in the text from the clipboard (with a long press). To copy an entire section to the clipboard, tap the first word then tap the last word. The whole section will be highlighted and copied to the clipboard. Additionally, you can enable active links for telephone numbers, email addreses and web links in Menu/Preferences. Any text recognized as a phone number, email address or web link will be colored and underlined. If you tap such text Android will attempt to bring up the appropriate app to handle it, phone dialler, email app or web browser.

File Formats

Two plain text file formats are available in Rdex, ASCII and UTF-8, and one AES-128 encrypted format. (Details of each file format are discussed in the file formats page.)

The UTF-8 file format is used for new cardfiles created on an Android device. UTF-8 is able to handle all symbols and characters in all writing systems. Characters will not get confused when shared across different computer systems (e.g. Windows and Android). However, Rdex UTF-8 format is not supported by versions of Rdex for Windows earlier than 1.5.


Rdex supports an AES-128 encrypted file format as of version 1.5.5 for Windows, 2.6.2 for Java and 2.4.17 for Android. (Details of the encryption algorithm are discussed in the file formats page.)

A default passphrase option is available. This allows all encrypted files to use the same passphrase stored in the Rdex application data. It is convenient in that encrypted files can be opened without typing in the passphrase. However, it is not very secure. Use it for protecting data files stored in the cloud or backup copies of the data on a flash drive.

For the higest security do not use the default passphrase option. Use an unguessable passphrase specific to the file you are protecting. The level of security is directly related to the length of the passphrase and how easily it is guessed.

Rdex encryption is not intended for high value data such as bank account numbers and sensitive account login credentials. For these you should use a password safe. Keepass is a free and popular password safe. A password safe encrypts each entry separately and only decrypts an entry when it is displayed. Rdex must decrypt the entire file so that the file can be searched. It remains decrypted in the memory while in use.

Set or clear the default passphrase using Encryption/Set Default Passphrase. Encrypt a file or change the passphrase using Encryption/Encrypt File. An option to use the default passphrase or type in a specific passphrase is given in the dialog. You can remove encryption by using Encryption/Remove File Encryption. The file will be saved in UTF-8 plain text format.

Rdex 2.4.18 for Android—Oct 2020

Rdex 2.4.17 for Android—May 2018

Rdex 2.4.16 for Android—Jly 2017

Rdex 2.4.15 for Android—Jun 2017

Rdex 2.4.14 for Android—Jly 2016

Rdex 2.4.13 for Android—May 2016

Rdex 2.4.12 for Android—Jan 2016

Rdex 2.4.11 for Android—Nov 2015

New in Rdex 2.4.10 for Android—Aug 2015

New in Rdex 2.4.7 for Android—Dec 2013

Source Code

Rdex 2.4.18 for Android source code.


This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details: www.gnu.org/licenses.