Battery Level Android App Using Android Studio

Introduction

In this article, I will show you how to create an Android app that shows the Battery Level of your device. A battery is an electrochemical cell (or enclosed and protected material) that can be charged electrically to provide a static potential for power or released electrical charge when needed.

 Requirements

• Android Studio version 2.3.3
• Little bit XML and JAVA knowledge.
• Android Emulator (or) Android mobile
• Download link (Android Studio)

Steps to be followed

Follow these steps to create the app using Android Studio. I have attached the source code too.

Step 1

Open Android Studio and start a new Android Studio Project.

Step 2

You can choose your application name and choose where your project is stored. If you wish to use C++ for coding the project, mark the "Include C++ support", and click "Next" button.

Step 3

Now, select the version of Android and select the target Android devices. We need to choose the SDK level which plays an important role to run the application.

Step 4

Now, add the activity and click "Next" button.

Step 5

Add Activity name and click "Finish".

Step 6

Go to activity_main.xml. This XML file contains the designing code for the Android app.



The XML code is given below.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp"
    tools:context=".MainActivity"
    android:background="#d5ebfa"
    >
    <ProgressBar
        android:id="@+id/pb"
        android:layout_width="150dp"
        android:layout_height="150dp"
        style="@android:style/Widget.ProgressBar.Horizontal"
     android:progressDrawable="@layout/progressbar_states"
        android:layout_centerInParent="true"
        />
    <TextView
        android:id="@+id/tv_percentage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="25dp"
        android:textColor="#000"
        android:layout_centerInParent="true"
        />
    <TextView
        android:id="@+id/tv_info"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="20dp"
        />
</RelativeLayout>

Step 7

Go to Main Activity.java. This Java program is the back-end language of Android.



The java code is given below.

package abu.battery;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.BatteryManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Window;
import android.widget.ProgressBar;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    private Context mContext;

    private TextView mTextViewInfo;
    private TextView mTextViewPercentage;
    private ProgressBar mProgressBar;
    private int mProgressStatus = 0;
    private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {

            int scale = intent.getIntExtra(BatteryManager.EXTRA_SCALE,-1);

            mTextViewInfo.setText("Battery Scale : " + scale)

            int level = intent.getIntExtra(BatteryManager.EXTRA_LEVEL,-1);
            mTextViewInfo.setText(mTextViewInfo.getText() + "\nBattery Level : " + level);
            float percentage = level/ (float) scale;
            mProgressStatus = (int)((percentage)*100);
            mTextViewPercentage.setText("" + mProgressStatus + "%");
            mTextViewInfo.setText(mTextViewInfo.getText() +
                    "\nPercentage : "+ mProgressStatus + "%");
            mProgressBar.setProgress(mProgressStatus);
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        requestWindowFeature(Window.FEATURE_ACTION_BAR);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mContext = getApplicationContext();
        IntentFilter iFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);
        mContext.registerReceiver(mBroadcastReceiver,iFilter);
        mTextViewInfo = (TextView) findViewById(R.id.tv_info);
        mTextViewPercentage = (TextView) findViewById(R.id.tv_percentage);
        mProgressBar = (ProgressBar) findViewById(R.id.pb);
    }
}

Step 8

Go to (App ⇒ Res ⇒Layout⇒progressbar_states.xml).



The Progressbar_states.xml code is given below.

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_height="match_parent" android:layout_width="match_parent">
    <item android:id="@android:id/background">
        <shape
            android:shape="oval">
            <stroke
                android:width="5dp"
                android:color="#d0d4d7"
                />
            <solid android:color="#eef2f5"/>
        </shape>
    </item>
    <item android:id="@android:id/progress">
        <clip android:clipOrientation="vertical" android:gravity="bottom">
            <shape
                android:shape="oval">
                <stroke
                    android:width="5dp"
                    android:color="#ff0001"
                    />
                <gradient
                    android:startColor="#7fc97c"
                    android:endColor="#99f396"
                    android:centerColor="#89e386"
                    android:angle="270"
                    android:gradientRadius="50"
                    android:centerY=".50"
                    />
            </shape>
        </clip>
    </item>
</layer-list>

Step 9

Now, go to menu bar and click "Make project" or press ctrl+f9 to debug the error.

Step 10

Then, click Run button or press shift+f10 to run the project. And, choose the virtual machine option and click OK.

Conclusion

We have successfully created the app that shows the battery level of our Android phone.