MainActivity JAVA

package com.android.ale.llaundry;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    EditText nama, alamat, telepon;
    Button  order;
    RadioGroup paket;
    @Override

    public boolean onCreateOptionsMenu (Menu menu){
        getMenuInflater().inflate(R.menu.menu, menu);
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item){
        switch (item.getItemId()){
            case R.id.action_contact:
                Intent intent_show = new Intent(MainActivity.this, ContactUs.class);
                intent_show.putExtra(Intent.EXTRA_TEXT,"Contact Us");
                startActivity(intent_show);

                //ke halaman tampilan semula
                return true;

            case R.id.action_home:
                Intent intent_delete = new Intent(MainActivity.this, MainActivity.class);
                intent_delete.putExtra(Intent.EXTRA_TEXT, "Data dari halaman main");
                startActivity(intent_delete);

                return true;

        }
        return super.onOptionsItemSelected(item);

    }


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



            nama = (EditText) findViewById(R.id.edit_nama);
        alamat = (EditText) findViewById(R.id.edit_alamat);
        telepon = (EditText) findViewById(R.id.edit_telepon);
        order = (Button) findViewById(R.id.button_order);
        paket = (RadioGroup) findViewById(R.id.group_paket);

        order.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {



                if (nama.getText().toString().length() == 0) {
                    nama.setError("Nama tidak boleh kosong!");
                } else if (nama.getText().toString().length() > 20) {
                    nama.setError("Nama Tidak Boleh lebih dari 20 Karakter");
                } else if (alamat.getText().toString().length() == 0) {
                    alamat.setError("Alamat tidak boleh kosong!");
                } else if (alamat.getText().toString().length() > 20) {
                    alamat.setError("Alamat Tidak Boleh lebih dari 20 Karakter");
                } else if (telepon.getText().toString().length() == 0) {
                    telepon.setError("Telepon tidak boleh kosong!");
                } else {
                    Toast.makeText(getApplicationContext(), "Order Berhasil! Silahkan tunggu kurir kami mengambil cucian",
                            Toast.LENGTH_SHORT).show();

                    String order = "Nama : " + nama + "\n";
                    order = order + "Alamat : " + alamat + "\n";
                    order = order + "Paket : " + paket + "\n";
                    order = order + "Telepon : " + telepon + "\n";

                }




            }

        });



    }
}