activty_main.xml

<?xml version="1.0" encoding="utf-8"?>
<ScrollView
    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"
    tools:context=".MainActivity">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <EditText
            android:id="@+id/name_field"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Name"
            android:inputType="textCapWords"/>

        <TextView
            android:text="topping"
            style="@style/HeaderTextStyle"/>
        <CheckBox
            android:id="@+id/whipped_cream_checkbox"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:paddingLeft="24dp"
            android:text="Whipped Cream"
            android:textSize="16sp"
            />
        <CheckBox
            android:id="@+id/chocolate_checkbox"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:paddingLeft="24dp"
            android:text="Chocolate"
            android:textSize="16sp"
            />
        <TextView
            android:text="Quantity"
            style="@style/HeaderTextStyle"/>
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            >

            <Button
                android:id="@+id/minus"
                android:layout_width="48dp"
                android:layout_height="48dp"
                android:layout_margin="8dp"
                android:text="-"
                android:onClick="decrement"/>
            <TextView
                android:id="@+id/quantity_text_view"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="2"
                android:layout_margin="8dp"
                android:textColor="@android:color/black" />

            <Button
                android:id="@+id/plus"
                android:layout_width="48dp"
                android:layout_height="48dp"
                android:layout_margin="8dp"
                android:onClick="increment"
                android:text="+" />
        </LinearLayout>
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Order"
            android:layout_margin="8dp"
            android:onClick="submitOrder"/>

    </LinearLayout>
</ScrollView>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.android.justjava">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

MainActivity.java

package com.example.android.justjava;
import java.text.NumberFormat;


import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

/**
 * This app displays an order form to order coffee.
 */
public class MainActivity extends AppCompatActivity {

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

    /**
     * This method is called when the order button is clicked.
     */
    int num=2;
    public void submitOrder(View view) {

        CheckBox whippedCreamCheckBox= (CheckBox) findViewById(R.id.whipped_cream_checkbox);
        boolean hasWhippedCream=whippedCreamCheckBox.isChecked();
//        Log.v("MainActivity","Has Whipped Cream: "+hasWhippedCream);

        CheckBox ChocoCheckBox= (CheckBox) findViewById(R.id.chocolate_checkbox);
        boolean hasChoco=ChocoCheckBox.isChecked();

        EditText text = (EditText) findViewById(R.id.name_field);
        String name=text.getText().toString();

        int price=calculatePrice(hasWhippedCream,hasChoco);
        String priceMessage=createOrderSummary(name,price,hasWhippedCream,hasChoco);

        Intent intent=new Intent(Intent.ACTION_SENDTO);
        intent.setData(Uri.parse("mailto:"));   //only email apps should handle this
        intent.putExtra(Intent.EXTRA_SUBJECT,"Just Java order for name "+name);
        intent.putExtra(Intent.EXTRA_TEXT,priceMessage);
        if(intent.resolveActivity(getPackageManager())!=null)
        {
            startActivity(intent);
        }


    }
    public void increment(View view) {
        if(num==100)
        {
            Toast.makeText(this,"You cannot have more than 100 cup of coffees",Toast.LENGTH_SHORT).show();
            return;
        }
        num=num+1;
        displayQuantity(num);
    }
    public void decrement(View view) {
        if(num==1)
        {
            Toast.makeText(this,"You cannot have less than 1 cup if coffee",Toast.LENGTH_SHORT).show();
            return;
        }
        num = num-1;
        displayQuantity(num);
    }


    /**
     * This method displays the given quantity value on the screen.
     */
    private void displayQuantity(int num) {
        TextView quantityTextView = (TextView) findViewById(R.id.quantity_text_view);
        quantityTextView.setText("" + num);
    }

    private String createOrderSummary(String name,int price, boolean addWhippedCream,boolean addChoco)
    {
        String priceMessage="Name = "+name;
        priceMessage+="\nHas Whipped Cream: "+addWhippedCream;
        priceMessage+="\nHas Chocolate: "+addChoco;
        priceMessage+="\nQuantity: "+num;
        priceMessage+="\nPrice $"+price ;
        priceMessage+="\nThank you!";
        return priceMessage;

    }
    /**
     * Calculates the price of the order based on the current quantity.
     *
     * @return the price
     */
    private int calculatePrice(boolean hasWhippedCream,boolean hasChoco) {

        int base=5;
        if(hasWhippedCream) {
            base= base+1;
        }
        if(hasChoco) {
            base=base+2;
        }
        return num*base;
    }
}

styles.xml

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">#009688</item>
        <item name="colorPrimaryDark">#00796B</item>
        <item name="colorAccent">#536DFE</item>
    </style>
<!--
    <style name="CustomText">
        <item name="android:textSize">20sp</item>
        <item name="android:textColor">#8379EE</item>
        <item name="android:textAllCaps">true</item>
    </style>
-->
    <style name="HeaderTextStyle">
        <item name="android:layout_width">wrap_content</item>
        <item name="android:layout_height">48dp</item>
        <item name="android:textSize">15sp</item>
        <item name="android:textColor">#8379EE</item>
        <item name="android:gravity">center_vertical</item>
        <item name="android:textAllCaps">true</item>
    </style>

</resources>