App Inventor Extensions

Geofence 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.

Nov 14th, 2025: Version 6: initial public version (prior versions are test versions).

Description

The Geofence Extension brings powerful, reliable location automation to your App Inventor projects. Create geofences that automatically trigger enter, exit, or dwell events - even when your app is closed or the device has rebooted. You can optionally display notifications, call background procedures via Itoo, or send web requests to your server or database whenever a geofence is triggered.

This extension is built on the official Google Geofencing API, ensuring high accuracy and excellent battery efficiency. A built-in foreground service keeps monitoring stable and prevents Android from unexpectedly stopping your app.

• Continues running after app is closed
• Automatically restarts after phone reboot
• Battery-optimized (uses Google Geofencing API)
• Clear documentation + ready-to-use demo app included
• Free version supports up to 2 geofences
• One-time purchase unlocks up to 100 geofences

Integration With Itoox / Background Webhooks

This extension uses Kumaraswamy's itoox-wrapper library, which allows direct invocation of Itoo (if installed) to call procedures from the background. This enables sending trigger data - e.g., via Web component - to your preferred backend: MySQL, Firebase, Google Sheets, email, or any web service.
After a device reboot, all geofences are automatically recreated.
Thanks to Simon for sponsoring this extension.
Minimum Android version: 8 (API 26)

Required permissions:
- android.permission.ACCESS_NETWORK_STATE
- android.permission.INTERNET
- android.permission.POST_NOTIFICATIONS
- android.permission.ACCESS_FINE_LOCATION
- android.permission.ACCESS_BACKGROUND_LOCATION
- android.permission.FOREGROUND_SERVICE
- android.permission.FOREGROUND_SERVICE_LOCATION
- android.permission.RECEIVE_BOOT_COMPLETED

Notes

• The free version is limited to 2 geofences. Use the example project to place geofences by clicking on the map, then close the app. When a geofence is triggered (Enter / Exit / Dwell), you will receive a notification and a voice tells you if you entered or exited a specific geofence.
• For stationary testing, use a fake location app like Lockito
• The extension also provides a LocationChanged event from the Fused Location Provider while the app is running in the foreground.
• This extension uses Google Play libraries and therefore cannot be combined with other extensions that also include these libraries. It only runs on devices with Google Play Services installed.

Properties

Notification properties

SmallIcon for notification. Recommended size is 96x96.

Title to be displayed in the notification. Default value is 'Geofence Trigger'.

Title to be displayed in the notification. Default value is 'Geofence Monitoring...'.

Geofence properties

Specifies whether a notification should be sent after a geofence was triggered. Default Value is true.

Loitering delay in milliseconds for transition type DWELL. Default = 10000 (i.e. 10 seconds).

Other properties

Reference screen for Itoo where the procedure 'OnTrigger' exists. It is advised to set the Reference screen property before Starting the service initially. Or if no property is set, the extension will take "Screen1" as the reference by default.

OnTrigger has the arguments transition, triggeredId, latitude, longitude and accuracy.

Methods

Geofence methods

Create geofence object. The id is a text of your choice to identify your geofence, radius is in meters, choose one or more transition types (enter, exit or dwell) just set to true or false, default transition types are enter and exit, expirationDuration in milliseconds can be set to -1 to have no expiration.

Remove geofence object of a given id. The id is a text of your choice to identify your geofence.

Remove all geofence objects.

Returns true if geofence id exists in the geofence list.

Return geofence objects in JSON format, i.e. a JSON array.

Get size of geofence list.

Return geofence ids as list.

Return geofence of a given id in JSON format, i.e. a JSON object.
Example blocks to get the transaction types of a given geofence id:

Start Geofence monitoring.
Note: You will have to build the app to be able to use this method.

Stop Geofence monitoring.
Note: You will have to build the app to be able to use this method.

Permission methods

Returns true, if Google Play Services is available.

Returns true, if GPS is enabled, else false.

Returns true, if basic location permissions have been granted, else false.

Returns true, if background location permission has been granted, else false.

Returns true, if post notifications permission has been granted, else false.

Request Basic Location Permission.
Note: You will have to build the app to be able to request location permission.

Request Background Location Permission.
Note: You will have to build the app to be able to request background location permission.

Ask for Post Notifications permission. Required starting from SDK 33.

Fused Location Provider methods

Start location tracking.

Stop location tracking.

Calculates the distance in meters from a given location to the edge of a geofence. If the location is inside the geofence, the distance is negative.

Other methods

Move task (i.e. the app) to the background.

Do not use the close application block together with this extension. The code behind the close application block terminates the app in an ungraceful way. Please use the MoveTaskToBack method instead.

Events

Geofence events

Indicates that geofence has been triggered.
Note: This event only will fire if the app is up and running.

Indicates that geofence monitoring has been started.

Indicates that geofence monitoring has been stopped.

Fused Location Provider events

Indicates that location changed event occurred.

Indicates that location tracking has been started.

Indicates that location tracking has been stopped.

Other events

Indicates that an Error occurred.

Example App "Geofence Simple"

Blocks

Screenshots

Test

Version 6 tested successfully on Samsung Galaxy A54 running Android 15.

Questions and Answers

Q1: How to troubleshoot geofence events?
A: `See the tips here.

Q2: How to test a geofence monitoring app?
A: Let me recommend you to use Lockito to make your phone follow a fake itinerary, for more information see`lockito-app.com.

Download

Download free version of TaifunGeofence extension (aix file), which is restricted to 2 geofences
Download geofence simple example project (aia file)

Buy the full version of the Geofence 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

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.

Back to top of page ...