🏃‍♂️ Fast : An Efficient Way to Build Extensions

[JEWEL]

An update is available v2.5.0

Date built: 04.03.25.14.53

---

• AnnotationProcessors now also allows non-YailType parameters. (ref)
• The Maven resolver has been updated to the latest version.

2.4.2:

• Added multi-threaded downloading technique on fast upgrade.

---

Thanks to @Kevinkun for identifying and helping to resolve this issue.

[TechHamara]

Hi @JEWEL One more issue

I recently created an extension and add Helpers methods. But helpers doc not generate.

[JEWEL]

Please tell me more! How was it written, and how should it have been?

[TechHamara]

Hi @JEWEL Check out pm

[JEWEL]

An update is available v2.6.0

Date built: 08.03.25.15.34

---

• Added blocks generator for AppInventor, Kodular, Niotron & AndroidBuilder by @Patryk_F
• UTF-8 encoding issues have been resolved.

[Devin_LU]

Hi everyone, I’m a beginner in Java and currently trying to use Fast to create an .aix extension for use in MIT App Inventor 2. However, I encountered an issue when trying to compile the project into an .apk.

Here are my .java, fast.yml, and assets/*.png files:
Fast_BluetoothHelper_v1_6.zip - Google Drive

Issue summary:

1. When I import the .aix into AI2, the extension’s icon doesn't display. (Could the image file be too large?)
2. The .aix can be imported into the AI2 website and runs fine via the MIT AI2 Companion simulator,
   but it fails to compile into an .apk – even when there’s no code block used in the project.

I noticed that if I use the default .java file provided by Fast instead of my own, the project can compile into an .apk without any problem.

I would really appreciate it if any experienced developer could take a look and help me figure out what’s wrong. Thanks a lot in advance!

If possible, please help me check whether there’s anything wrong with my .java or fast.yml settings.

[Idriss_Chrifi_alaoui]

Hey, your URL miss fast.yml, and assets/*.png

@Devin_LU

fast.yml, and assets/*.png

And can u share with us the error message!

[Devin_LU]

Sorry, I forgot to include some files in the previous upload.
Here is the updated compressed folder with all necessary files (.java, fast.yml, and assets/*.png):
Fast_BluetoothHelper_v1_6.zip - Google Drive

[Idriss_Chrifi_alaoui]

U have a lot of problems.
Do u used ai to create this extension?

[Devin_LU]

@Idriss_Chrifi_alaoui

U have a lot of problems.

Oh No! Really? Oh no... that’s so disappointing.

@Idriss_Chrifi_alaoui

Do u used ai to create this extension?

I’ve been learning through web resources and AI.
(But in the end... ~)
Could you please let me know what went wrong?

[Idriss_Chrifi_alaoui]

I will fix it for you

[JEWEL]

@Devin_LU

I’ve been learning through web resources and AI.

Here are a few open-source projects you might find helpful to learn from.

Open‐Source‐Projects

[Idriss_Chrifi_alaoui]

Update:
icon size 24/24px

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="com.LLL.BluetoothHelper">

    <uses-permission android:name="android.permission.BLUETOOTH"/>
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <uses-permission android:name="android.permission.BLUETOOTH_SCAN"/>
    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT"/>


</manifest>

fast.yml

author: LLL

min_sdk: 7

proguard: true

R8: true

desugar_sources: false

desugar_deps: false

desugar_dex: true

gen_docs: true

auto_version: true

deannonate: true

filter_mit_classes: false

BluetoothHelper.java

package com.LLL.BluetoothHelper;

import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.*;
import android.location.LocationManager;
import android.os.Build;
import android.provider.Settings;
import android.content.pm.PackageManager;
import com.google.appinventor.components.annotations.*;
import com.google.appinventor.components.common.ComponentCategory;
import com.google.appinventor.components.runtime.*;
import java.util.HashSet;
import java.util.ArrayList;
import java.util.List;

@DesignerComponent(version = 8,
        description = "Bluetooth Helper Extension - by LLL. Version 1.6 . Bluetooth Helper Extension for App Inventor.\n" +
                "  Includes: Bluetooth name lookup, GPS check, permission request,\n" +
                "  device discovery (no internal deduplication), events for Bluetooth/GPS state changes,\n" +
                "  and checking individual permissions.",
        category = ComponentCategory.EXTENSION,
        nonVisible = true,
        iconName = "jewelry.png")

public class BluetoothHelper extends AndroidNonvisibleComponent implements Component, ActivityResultListener {

    private final Activity activity;
    private final Context context;
    private final BluetoothAdapter bluetoothAdapter;
    private final BroadcastReceiver receiver;
    private final BroadcastReceiver stateChangeReceiver;

    public BluetoothHelper(ComponentContainer container) {
        super(container.$form());
        activity = container.$context();
        context = container.$context();
        bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

        receiver = new BroadcastReceiver() {
            public void onReceive(Context context, Intent intent) {
                String action = intent.getAction();
                if (BluetoothDevice.ACTION_FOUND.equals(action)) {
                    BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                    if (device != null) {
                        String name = device.getName();
                        String address = device.getAddress();
                        if (address != null) {
                            if (name == null || name.isEmpty()) {
                                name = "Unknown";
                            }
                            DeviceFound(name, address);
                        }
                    }
                }
            }
        };

        stateChangeReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(intent.getAction())) {
                    int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, -1);
                    if (state == BluetoothAdapter.STATE_ON) {
                        BluetoothEnabled();
                    } else if (state == BluetoothAdapter.STATE_OFF) {
                        BluetoothDisabled();
                    }
                } else if (LocationManager.PROVIDERS_CHANGED_ACTION.equals(intent.getAction())) {
                    if (IsLocationEnabled()) {
                        LocationEnabled();
                    } else {
                        LocationDisabled();
                    }
                }
            }
        };

        IntentFilter filter = new IntentFilter();
        filter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);
        filter.addAction(LocationManager.PROVIDERS_CHANGED_ACTION);
        context.registerReceiver(stateChangeReceiver, filter);
    }

    @SimpleFunction(description = "Check if the specific permission is granted (e.g. android.permission.BLUETOOTH_CONNECT)")
    public boolean HasPermission(String permissionName) {
        return Build.VERSION.SDK_INT < 23 ||
                activity.checkSelfPermission(permissionName) == PackageManager.PERMISSION_GRANTED;
    }

    @SimpleFunction(description = "Get this device's Bluetooth name")
    public String GetBluetoothName() {
        return bluetoothAdapter != null ? bluetoothAdapter.getName() : "Unavailable";
    }

    @SimpleFunction(description = "Check if Bluetooth is enabled")
    public boolean IsBluetoothEnabled() {
        return bluetoothAdapter != null && bluetoothAdapter.isEnabled();
    }

    @SimpleFunction(description = "Request user to enable Bluetooth (system dialog)")
    public void RequestEnableBluetooth() {
        if (bluetoothAdapter != null && !bluetoothAdapter.isEnabled()) {
            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            activity.startActivity(enableBtIntent);
        }
    }

    @SimpleFunction(description = "Check if location service (GPS) is enabled")
    public boolean IsLocationEnabled() {
        LocationManager lm = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
        return lm.isProviderEnabled(LocationManager.GPS_PROVIDER);
    }

    @SimpleFunction(description = "Show location enable dialog (opens settings)")
    public void ShowLocationPromptDialog() {
        Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
        activity.startActivity(intent);
    }

    @SimpleFunction(description = "Return list of required permissions by Android version")
    public List<String> GetRequiredPermissions() {
        List<String> permissions = new ArrayList<>();
        if (Build.VERSION.SDK_INT >= 31) {
            permissions.add("android.permission.BLUETOOTH_SCAN");
            permissions.add("android.permission.BLUETOOTH_CONNECT");
            permissions.add("android.permission.ACCESS_FINE_LOCATION");
        } else if (Build.VERSION.SDK_INT >= 23) {
            permissions.add("android.permission.ACCESS_FINE_LOCATION");
        }
        return permissions;
    }

    @SimpleFunction(description = "Start scanning for nearby Bluetooth devices")
    public void StartDiscovery() {
        if (bluetoothAdapter != null && bluetoothAdapter.isEnabled()) {
            IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
            context.registerReceiver(receiver, filter);
            bluetoothAdapter.startDiscovery();
        }
    }

    @SimpleFunction(description = "Stop scanning for Bluetooth devices")
    public void StopDiscovery() {
        if (bluetoothAdapter != null) {
            bluetoothAdapter.cancelDiscovery();
            try {
                context.unregisterReceiver(receiver);
            } catch (IllegalArgumentException e) {
                // receiver not registered
            }
        }
    }

    @SimpleFunction(description = "Request necessary permissions dynamically (if not already granted)")
    public void RequestRequiredPermissions() {
        List<String> permissions = GetRequiredPermissions();
        if (permissions != null && permissions.size() > 0) {
            activity.requestPermissions(permissions.toArray(new String[0]), 12345);
        }
    }

    @SimpleFunction(description = "Check if all required permissions have been granted")
    public boolean HasRequiredPermissions() {
        if (Build.VERSION.SDK_INT >= 31) {
            return activity.checkSelfPermission("android.permission.BLUETOOTH_SCAN") == 0 &&
                   activity.checkSelfPermission("android.permission.BLUETOOTH_CONNECT") == 0 &&
                   activity.checkSelfPermission("android.permission.ACCESS_FINE_LOCATION") == 0;
        } else if (Build.VERSION.SDK_INT >= 23) {
            return activity.checkSelfPermission("android.permission.ACCESS_FINE_LOCATION") == 0;
        }
        return true;
    }

    @SimpleEvent(description = "Triggered when a Bluetooth device is found (name and MAC address)")
    public void DeviceFound(String deviceName, String deviceAddress) {
        EventDispatcher.dispatchEvent(this, "DeviceFound", deviceName, deviceAddress);
    }

    @SimpleEvent(description = "Triggered when Bluetooth is successfully enabled")
    public void BluetoothEnabled() {
        EventDispatcher.dispatchEvent(this, "BluetoothEnabled");
    }

    @SimpleEvent(description = "Triggered when Bluetooth is turned OFF")
    public void BluetoothDisabled() {
        EventDispatcher.dispatchEvent(this, "BluetoothDisabled");
    }

    @SimpleEvent(description = "Triggered when GPS/Location service is enabled")
    public void LocationEnabled() {
        EventDispatcher.dispatchEvent(this, "LocationEnabled");
    }

    @SimpleEvent(description = "Triggered when GPS/Location service is turned OFF")
    public void LocationDisabled() {
        EventDispatcher.dispatchEvent(this, "LocationDisabled");
    }

    @Override
    public void resultReturned(int requestCode, int resultCode, Intent data) {
    }
}

[Spicy_Topics]

@JEWEL

Added blocks generator for AppInventor, Kodular, Niotron & AndroidBuilder by @Patryk_F

Hi jewel, welldone for your work and dedication. By the way do you have any tutorial regarding the usage of your builder? Just bow i upgraded my pc to w11. So just share with me any tutorial.

Thanks

[Idriss_Chrifi_alaoui]

Hi,
I am trying to create an extension for MIT App Inventor using Fast CLI and would like to integrate the OpenCV library. When converting the opencv.aar file to library.jar, the .so files are not included, causing the library not to work when the extension is used.

I understand that .so files are typically not included in a JAR, but is there any way to include .so files within the extension so it works correctly in MIT App Inventor?

Any suggestions or solutions would be greatly appreciated! Thank you.

[JEWEL]

@Idriss_Chrifi_alaoui

is there any way to include .so files within the extension

It'll be possible once this PR is merged. I'm putting this feature in FAST's next major version since Niotron and AndroidBuilder already have it.

Implementing .aar libraries for extensions.

@Spicy_Topics

do you have any tutorial regarding the usage of your builder?

I plan to release several tutorial videos demonstrating FAST project creation, build processes, and installation procedures.

[Kumaraswamy]

@Idriss_Chrifi_alaoui

I understand that .so files are typically not included in a JAR, but is there any way to include .so files within the extension so it works correctly in MIT App Inventor?

Is it possible to add native (.so) libraries to extensions

It is completely possible to use .so libraries in App Inventor. You just have to include it in the assets, (x84 family, arm family versions x7 x8). After you have included them, at runtime, query about the device's supported ABIs which you are going to match(x84 and arm family) with the included .so native assets. Then you have to unpack the native asset into a place accessibly by the application, preferably the files directory. Then you can manually start the library using System.load(path). A…

[Kevinkun]

including the so file in extension is not possible maybe, since some so files are very big, that will make the aix too big to import to the ai2 server.

I have made an OpenCV extension, the so files can be downloaded from internet when first time run, or repack the apk file by adding so files to assets.

[Idriss_Chrifi_alaoui]

Thank you very much for the clarification!

I will try these methods and see which one works best for me. Thanks again for your help and for sharing your expertise

[mahmoud_hooda]

@Kevinkun

file by adding so files to assets

Can i put file to assets folder of apk without uploading it in the assets of the project?