Android for Beginners : Cookies Solution Code

activity_main.xml

<LinearLayout 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"
    android:background="#B388FF"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/android_cookie_image_view"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:scaleType="centerCrop"
        android:src="@drawable/before_cookie"
        android:text="@string/hello_world" />

    <TextView
        android:id="@+id/status_text_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="16dp"
        android:layout_marginRight="16dp"
        android:layout_marginTop="16dp"
        android:text="I'm so hungry"
        android:textColor="@android:color/white"
        android:textSize="34sp" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="16dp"
        android:text="Eat cookie"
        android:onClick="eatCookie" />

</LinearLayout>

MainActivity.java

package com.example.android.cookies;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;


public class MainActivity extends AppCompatActivity {

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

    /**
     * Called when the cookie should be eaten.
     */
    public void eatCookie(View view) {
        // Find a reference to the ImageView in the layout. Change the image.
        ImageView imageView = (ImageView) findViewById(R.id.android_cookie_image_view);
        imageView.setImageResource(R.drawable.after_cookie);

        // Find a reference to the TextView in the layout. Change the text.
        TextView textView = (TextView) findViewById(R.id.status_text_view);
        textView.setText("I'm so full");
    }
}

Can anybody help me? How to resolve these errors?