Want to program app to connect to bluetooth device

Hopefully someone can send me in the right direction.

I am attempting to program a simple app that connects via bluetooth to a piece of fire alarm equipment. The overall goal is that when the fire alarm is triggered on the equipment, the app shows the fire alarm status via simple binary Alarm/No alarm function.

What I am having trouble with is programming the bluetooth function. I have experience with Java but not with a bluetooth functionality. I want to program a button that searches and connects to bluetooth devices.

Here is the bit of code I've started in MainActivity.kt

package com.example.myapplication

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val daqButton = findViewById<Button>(R.id.daqButton)

        daqButton.setOnClickListener {

        }
    }
}

And here's the code I've started in AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myapplication">
    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />

    <!-- If your app targets Android 9 or lower, you can declare
         ACCESS_COARSE_LOCATION instead. -->
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Any tips or tricks to help me accomplish this is greatly appreciated! Thanks in advance

Well, the easiest way to implement that is to use a third-party library like this Bluetooth Library.

• Include the library dependency into your app module gradle file.
• set up the library in your app as described in the library's repository on GitHub.
• If you need to connect to the device from the app you have to implement the scanning functionality yourself by providing a ListView and the logic to insert the discovered Bluetooth devices. Refer to the Github repository documentation you will find some callbacks that you can use to implement the search, discovery, and connection functionalities.
• If you prefer to follow the easy way just connect to the Bluetooth device externally from your device's Bluetooth manager, then you can communicate with the device as follows.

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main)

    bluetooth = new Bluetooth(this);
    bluetooth.send("Your message");

}

• If you want to receive back some response from the other Bluetooth device you have to listen to the DeviceCallback() you will find its description in the Github repository

Note

You have to add some permissions in the Manifest files which are

• BLUETOOTH
• BLUETOOTH_ADMIN
• ACCESS_COARSE_LOCATION

In order to give access to your app to use the Bluetooth

• You can follow this example code provided by the library