Android Kotlin: How to get device battery health programmatically

This code snippet demonstrates how to retrieve the device's battery health status programmatically in an Android application written in Kotlin. It utilizes the Android Broadcast mechanism to listen for changes in the battery state and update the UI accordingly.

Code Breakdown:

  1. Broadcast Receiver:

    • A BroadcastReceiver subclass is defined within the MainActivity class. This receiver listens for specific system events (broadcasts) related to the battery.

  2. onReceive Method:

    • This method is invoked whenever the registered broadcast is received. It retrieves the battery health information from the Intent object using the BatteryManager.EXTRA_HEALTH extra key.

  3. Battery Health Determination:

    • A when expression is used to interpret the integer value obtained from the EXTRA_HEALTH key. Each possible value corresponds to a specific battery health state like "Good", "Dead", or "Overheat". A default case handles unknown or error conditions.

  4. UI Update:

    • The retrieved battery health status is displayed on the screen using the textView element referenced by its ID. The text is formatted as "Battery Health : <health_status>".

  5. onCreate Method:

    • The onCreate method sets up the broadcast receiver functionality.
    • An IntentFilter object is created to specify the type of broadcast we're interested in (battery change event).
    • Finally, the registerReceiver method registers the created receiver with the system, along with the defined filter.

  6. activity_main.xml:

    • This file defines the layout of the activity. In this case, it's a simple layout with a single TextView element to display the battery health information.

Summary

This code provides a basic example of fetching the device's battery health programmatically in an Android application. By registering a broadcast receiver and interpreting the received information, the app can display the current battery health status to the user. It's important to note that this approach only provides a limited set of health states and may not offer detailed diagnostics available on specific devices.


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?) {
            val health = when(intent?.getIntExtra(
                BatteryManager.EXTRA_HEALTH,-1
            )){
                // determine the battery health from intent
                BatteryManager.BATTERY_HEALTH_COLD -> "Cold"
                BatteryManager.BATTERY_HEALTH_DEAD -> "Dead"
                BatteryManager.BATTERY_HEALTH_GOOD -> "Good"
                BatteryManager.BATTERY_HEALTH_OVERHEAT -> "Over heat"
                BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE -> "Over voltage"
                BatteryManager.BATTERY_HEALTH_UNKNOWN -> "Unknown"
                BatteryManager
                    .BATTERY_HEALTH_UNSPECIFIED_FAILURE -> "Unspecified failure"
                else -> "Error"
            }

            textView.text = "Battery Health : $health"
        }
    }

    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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