App Inventor Extensions

SMS Receiver Extension

See the App Inventor Extensions document about how to use an App Inventor Extension.

For questions about this extension or bug reports please start a new thread in the App Inventor community. Thank you.

For feature requests please contact me by email. To be a sponsor of a new method already is possible starting from only 10 USD! With your contribution you will help the complete App Inventor community. Thank you.

Jul 3th, 2024: Version 1: initial version.

Apr 24th, 2025: Version 2: Send Sms functionality and OnReceive background event handler added to forward received SMS

Description

SMS Receiver extension.
Use this extension to receive SMS while your app is not running. The including background functionality in Version 2 offers to forward received SMS by sending it to another number or forwarding it by email, etc. You have 4 different possibilities to trigger an action after an SMS has received depending on property StartMode

1. Only Notification
   Display a notification. After clicking the notification, the app will be started and screen "LockScreen" will be opened. In case that screen does not exist, Screen1 will be opened.
2. Start Above Lock Screen or Notification
   If the device is locked, the screen called "LockScreen" of the app will be opened above the lockscreen of the device! After closing the app, the device still will be locked. If the device is unlocked, display a notification. After clicking the notification, the app will be started and screen "LockScreen" will be opened. This is the recommended start mode to not disturb the user while using other apps, see also here.
3. Start Always
   The app will always start and open the screen called "LockScreen" no matter the state of the device. This might be annoying if the user is in a phone call or using another app. For this mode, additionally the permission "Appear On Top" is required.
4. Only Background Processing
   Trigger some background functionality to forward the received SMS.

Note: Displaying an app above the lockscreen (also known as full screen intent) requires for Android 14+ devices additionally full screen intent permission. After each app update this permission needs to be refreshed again! Its use is restricted: For apps targeting Android 14 (API level 34) or higher, apps that are allowed to use this permission are limited to those that provide calling and alarms only. You can use method HasFullScreenIntentPermission to check if your app has the permission; if not or if your app has not been approved for default enabling use of full screen intents you can use method AskForFullScreenIntentPermission to launch the settings page where users can grant the permission.

Required permissions: android.permission.RECEIVE_SMS, android.permission.SYSTEM_ALERT_WINDOW, android.permission.POST_NOTIFICATIONS, android.permission.DISABLE_KEYGUARD, android.permission.WAKE_LOCK, android.permission.USE_FULL_SCREEN_INTENT
In version 2 android.permission.SEND_SMS has been added to forward received sms to another number.

Note: To publish an app in Google Play using the sensitive permission RECEIVE_SMS or SEND_SMS might be a challenge. You have to find a good use case, see also here.

Properties

Reference screen for Itoo where the procedure 'OnReceive' exists. If no property is set, the extension will take "Screen1" as the reference by default.

OnReceive has the arguments phoneNumber and message.

Note: The OnReceive event handler also will be called if the app is in the foreground!

Returns/Specifies the notification color.

Returns/Specifies the SmallIcon for notification. Recommended size is 96x96.

StartMode after SMS has been received.
Possible values are: 1, 2,3 or 4. (1 = Only notification, 2 = Start Above Lock Screen or Notification, 3 = Start Always, 4 = Only Background Processing).

Methods

Returns true, if receive sms permission has been granted, else false.

Returns true, if send sms permission has been granted, else false.

Ask for both RECIVE_SMS and SEND_SMS permissions.

Returns true, if post notifications permission has been granted, else false. Required starting from API Level 33.

Ask for Post Notifications permission. Required starting from API Level 33.

If user likes to always start the app, special permission is required. Using this method, you can check, if the permission has been granted.

Open Appear On Top Settings to enable always starting the app. Required starting from API Level 23.

Returns true, if full screen intent permission has been granted, else false. Required starting from API Level 34.

Ask for Full Screen Intent permission. Required starting from API Level 34 for apps that did not complete the Google Play declaration or have not been approved for default enabling use of full screen intents.

Cancel the current notification.

Sends a text message via SMS.

Events

Event indicating that sms has been sent.

Example App: Receive SMS

Blocks Screen1

Blocks LockScreen

Screenshots

The example app gives a short overview about its purpose and asks for 2 basic permissions to receive sms and post notifications

Depending on the start mode, further permissions are required. Both Start Modes "Start Above Lock Screen or Notification" and "Start Always" require Full Screen Alert permission. Start Mode "Start Always" requires Allways On Top permission.

Example blocks for background processing: forward sms to another phone number

Example blocks for background processing: forward sms by email

The example uses my mail extension to send the email. This extension can be purchased seperately here.

Test

Tested successfully on Samsung Galaxy A54 running Android 14 and Google Nexus 5X running Android 8.1.

Buy the SMS Receiver extension for App Inventor

You can buy this extension (aix file).
With your payment you accept the terms and conditions below.

Payment options

Then send me the transaction id by email and tell me the extension you are interested in.

After having received your payment I will be happy to send the download link to you. Please let me know your Google account! I usually will send the download link not later than 24 hours after having received your payment.
Thank you! Taifun

After buying the extension you additionally will receive the following projects

• receive sms example project
• forward sms to another phone number project

Terms and Conditions

• You are buying a digital product and agree to the No Return, No Refund Policy.
• You have tested the example app successfully on your device before buying the extension.
• You can use the extension in as many projects as you like and pass the generated apk files to as much end users as you like, also of course you can publish your apk files to Google Play and other services
• This is a single user license for you as App Inventor developer, which means, the extension (aix file) is only for you to use. You are not allowed to pass a paid extension (aix file) or a project (aia file) which contains a paid extension to someone else, to post it in one of the communities or to distribute it to others. In case you are interested in a multiple user license, please contact me by email.
• There are a lot of different Android devices available in the market. I'm not able to test the example on all these devices and therefore also can not guarantee, that the example is running on your device.
• THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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