I have been working on making my app change background color once the user clicks on Menu but I don't understand why it doesn't work. I don't have any warnings or errors!

My activity\_main.xml:

```
<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"
android:id="@+id/utilayout"
tools:context=".MainActivity"
>

<TextView
    android:id="@+id/hello1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world" />

<ImageView
    android:id="@+id/imageView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/hello1"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="80dp"
    android:src="@drawable/ic_launcher" android:contentDescription="@string/hello_world"/>

```

My MainActivity.java:

```
package com.example.menu;
import android.os.Bundle; 
import android.app.Activity; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.widget.RelativeLayout; 
import android.widget.TextView;

public class MainActivity extends Activity {

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

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

public boolean onOptionsItemsSelected(MenuItem item)
{
    RelativeLayout bkgr = (RelativeLayout) findViewById(R.id.utilayout);

    switch(item.getItemId())
    {
    case R.id.action_black: 
        bkgr.setBackgroundResource(R.color.black);
        return true;

    case R.id.action_red: 
        bkgr.setBackgroundResource(R.color.red);
        return true;

    case R.id.action_hello:
        TextView tv = (TextView) findViewById(R.id.hello1);
        tv.setText("What up people?");
        return true;

    default: return super.onOptionsItemSelected(item);
    }
}
}

```

main.xml (in menu)

```
<menu xmlns:android="http://schemas.android.com/apk/res/android" >

  <item
    android:id="@+id/action_red"
    android:orderInCategory="100"
    android:showAsAction="never"
    android:title="@string/action_red"/>
  <item
    android:id="@+id/action_black"
    android:orderInCategory="200"
    android:showAsAction="never"
    android:title="@string/action_black"/>
    <item
    android:id="@+id/action_hello"
    android:orderInCategory="300"
    android:showAsAction="never"
    android:title="@string/hello"/>

```