Android Tutorial - Android Development Guru

MainActivity.java package com.AndroidDevelopmentGuru.custom_toast; import android.app.Activity; import android.os.Bundle; import android.view.Gravity; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnClickListener; import android.view.ViewGroup; import android.widget.Button; import android.widget.Toast; public class MainActivity extends Activity {     Button btn;     @Override