android kotlin - Get battery capacity programmatically

MainActivity.kt


package com.example.jetpack

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


class MainActivity : AppCompatActivity() {

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

        // get battery capacity and show it on text view
        applicationContext.batteryCapacity?.apply {
            textView.text = "Battery Capacity\n${this.toInt()} mAh"
        }
    }
}


// extension property to get battery capacity
val Context.batteryCapacity:Double?
    get() {
        val powerProfileClass = "com.android.internal.os.PowerProfile"
        try {
            (Class.forName(powerProfileClass).getConstructor(Context::class.java)
                .newInstance(this)).apply {

                    return Class.forName(powerProfileClass)
                        .getMethod("getAveragePower", String::class.java)
                        .invoke(this, "battery.capacity") as Double
                }

        }catch (e: Exception){
            e.printStackTrace()
        }
        return null
    }

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>