Android application for stop watch

Create a Stopwatch Application in android which contain  Start, Pause and Stop Button. and also perform the functions. 

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center"
    tools:context=".MainActivity">

    <Chronometer
        android:id="@+id/chronometer"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30sp"/>
    <Button
        android:id="@+id/btn_start"
        android:layout_width="200dp"
        android:layout_height="80dp"
        android:layout_marginTop="20dp"
        android:onClick="startTime"
        android:text="Start"/>
    <Button
        android:id="@+id/btn_stop"
        android:layout_width="200dp"
        android:layout_height="80dp"
        android:layout_marginTop="20dp"
        android:onClick="stopTime"
        android:text="PAUSE"/>
    <Button
        android:id="@+id/btn_reset"
        android:layout_width="200dp"
        android:layout_height="80dp"
        android:layout_marginTop="20dp"
        android:onClick="restartTime"
        android:text="STOP"/>

</LinearLayout>

MainActivity.java

package com.example.stopwatch;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.os.SystemClock;
import android.view.View;
import android.widget.Chronometer;

public class MainActivity extends AppCompatActivity {
    Chronometer chronometer;
    boolean runninng=false;
    private long pauseOffset;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        chronometer=findViewById(R.id.chronometer);
    }
    public void startTime(View v)
    {
        if(!runninng)
        {
            chronometer.setBase(SystemClock.elapsedRealtime()-pauseOffset);
            chronometer.start();
            runninng=true;
        }
    }
    public void stopTime(View v)
    {
        if(runninng)
        {
            chronometer.stop();
            pauseOffset=SystemClock.elapsedRealtime()-chronometer.getBase();
            runninng=false;
        }
    }
    public void restartTime(View v)
    {
       chronometer.setBase(SystemClock.elapsedRealtime());
    }
}