Android Kotlin: How to get battery temperature programmatically

Introduction

This code snippet showcases how to retrieve the device's battery temperature programmatically in an Android application written in Kotlin. It utilizes the Android Broadcast mechanism to listen for battery-related changes and extract the temperature value.

Breakdown

The code is implemented within the MainActivity.kt file. Here's a step-by-step breakdown:

  1. Broadcast Receiver:

    • A BroadcastReceiver subclass is defined to handle incoming broadcasts related to battery changes.
    • The onReceive method is overridden to handle the received intent.

  2. Obtaining Battery Temperature:

    • Inside onReceive, the intent object carries information about the battery change.
    • The getIntExtra method with BatteryManager.EXTRA_TEMPERATURE as the key retrieves the battery temperature value in tenths of a degree Celsius (integer).
    • The retrieved value is converted to a float and divided by 10 to get the actual temperature.

  3. Displaying Temperature:

    • The formatted temperature string, including the degree symbol (°C), is assigned to the text property of the textView in the layout.

  4. Activity Setup:

    • The onCreate method of the MainActivity class is responsible for setting up the broadcast receiver.
    • An IntentFilter object is created to specify the type of broadcast we're interested in (battery changes - Intent.ACTION_BATTERY_CHANGED).
    • Finally, the registerReceiver method registers the previously defined broadcast receiver with the specified intent filter.

  5. Layout (activity_main.xml):

    • This file defines the user interface layout of the activity. In this case, it simply contains a single TextView element where the battery temperature will be displayed.

Summary

This code demonstrates a practical approach to programmatically access and display the device's battery temperature in an Android app. By leveraging the BroadcastReceiver and BatteryManager functionalities, the application can stay updated on battery changes and provide users with this valuable information.


MainActivity.kt 

package com.example.jetpack

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.content.IntentFilter
import android.os.BatteryManager
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*


class MainActivity : AppCompatActivity() {

    // initialize a new broadcast receiver instance
    private val receiver:BroadcastReceiver = object: BroadcastReceiver(){
        override fun onReceive(context: Context?, intent: Intent?) {
            // get battery temperature programmatically from intent
            // battery temperature in tenths of a degree centigrade
            intent?.apply {
                val temp = getIntExtra(
                    BatteryManager.EXTRA_TEMPERATURE,0
                )/10F

                // show the battery temperate in text view
                textView.text = "Battery Temperature\n\n$temp${0x00B0.toChar()}C"
            }
        }
    }

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

        // initialize a new intent filter instance
        val filter = IntentFilter(Intent.ACTION_BATTERY_CHANGED)

        // register the broadcast receiver
        registerReceiver(receiver,filter)
    }
}
activity_main.xml 

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/constraintLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#EDEAE0"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:fontFamily="sans-serif-condensed"
        android:gravity="center"
        android:padding="32dp"
        android:textColor="#0014A8"
        android:textSize="35sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.25"
        tools:text="TextView" />

</androidx.constraintlayout.widget.ConstraintLayout>
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