Fun Facts app crashes after adding ID to relative Layout

This is my FunFacts.java

package com.example.owner.funfacts;

import android.graphics.Color; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.RelativeLayout; import android.widget.TextView;

import java.util.Random;

public class MainActivity extends AppCompatActivity { private FactBook mFactBook = new FactBook(); private ColorWheel mColorWheel = new ColorWheel(); // Declare our view variables private TextView mFactTextView; private Button mShowFactButton; private RelativeLayout mRelativeLayout;

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

    // Assign the views from the layout file to the corresponding variables
    mFactTextView = (TextView) findViewById(R.id.factTextView);
    mShowFactButton = (Button) findViewById(R.id.showFactButton);
    mRelativeLayout = (RelativeLayout) findViewById(R.id.relativeLayout);


    View.OnClickListener listener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
      String fact  = mFactBook.getFact();
      int Color = mColorWheel.getColor();


            //Update the screen with our dynamic fact
            mFactTextView.setText(fact);
            mRelativeLayout.setBackgroundColor(Color);
            mShowFactButton.setTextColor(Color);

        }
    };
    mShowFactButton.setOnClickListener(listener);

}

}

And this is my activity_fun_facts.xml

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:layout="@+id/relativeLayout" tools:context="com.example.owner.funfacts.MainActivity" android:background="#51b46d">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Did you know?"
    android:id="@+id/TextView"
    android:background="#80ffffff" />

<Button
    android:text="Show Another Fun Fact"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="23dp"
    android:id="@+id/showFactButton"
    android:background="@android:color/white"
    android:textColor="#51b46d"/>

<TextView
    android:text="Ants stretch when they wake up in the morning"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="24sp"
    android:textColor="@android:color/white"
    android:id="@+id/factTextView"
    android:layout_below="@+id/TextView"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginTop="157dp" />

</RelativeLayout>

This the message I get in my messages log after running the code;

Information:Gradle tasks [:app:clean, :app:generateDebugSources, :app:mockableAndroidJar, :app:prepareDebugUnitTestDependencies, :app:generateDebugAndroidTestSources, :app:assembleDebug] Information:BUILD SUCCESSFUL Information:Total time: 36.451 secs Information:0 errors Information:0 warnings Information:See complete output in console

And the screen on the emulator just reads unfortunately, Fun Facts has stopped, after I click the Show Another Fun Fact button.

Thanks for your answer Floris, So I changed

setContentView(R.layout.activity_main); to setContentView(R.layout.activity_fun_facts); through rename>refactor.

But Still my Fun Facts App crashes. I don't think that my app should crash on mFactTextView.setText(fact); because I have the facts referred to by the above method stored in a Factbook.java.

Also, I don't think that the mFactTextView is null because there is a factTextView ID in the view defined below.

<TextView android:text="Ants stretch when they wake up in the morning" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="24sp" android:textColor="@android:color/white" android:id="@+id/factTextView" android:layout_below="@+id/TextView" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:layout_marginTop="157dp" />

If I am wrong Floris, please what steps do you think I should take to correct this problem?

Thanks Flores , I have finally resolved the issue .

I have the same problem with the dynamic background how do I solve it? when I comment that the app works fine help!!!