Button Example

Screenshots :

activity_main.xml :

<?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"
    tools:context="com.chantisandroid.buttonexample.MainActivity">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="clickme"
        android:id="@+id/button_click"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="82dp" />

</RelativeLayout>

MainActivity.java :

package com.chantisandroid.buttonexample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    Button click;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        click = (Button)findViewById(R.id.button_click);
        click.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        Toast.makeText(this,"button is working",Toast.LENGTH_LONG).show();
    }
}