App cannot run even without errors in code

Here are my files: package com.example.darek.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 FunFactsActivity extends AppCompatActivity {



//Declare our View variables

private TextView mFactTextView;
private Button mShowFactButton;
private RelativeLayout mRelativeLayout;
    private FactBook mFactBook = new FactBook();
    private ColorWheel mColorWheel= new ColorWheel();

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

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


    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);

            //Update the background color
            mRelativeLayout.setBackgroundColor(color);

        }
    };
    mShowFactButton.setOnClickListener(listener);

}

}

package com.example.darek.funfacts;

import java.util.Random;

/**

• Created by Darek on 12.07.2016. */ public class FactBook {

  private String[] mFacts ={ "Ants stretch when they wake up in the morning.", "Ostriches can run faster than horses.", "Olympic gold medals are actually made mostly of silver.", "You are born with 300 bones; by the time you are an adult you will have 206.", "It takes about 8 minutes for light from the Sun to reach Earth.", "Some bamboo plants can grow almost a meter in just one day.", "The state of Florida is bigger than England.", "Some penguins can leap 2-3 meters out of the water.", "On average, it takes 66 days to form a new habit.", "Mammoths still walked the earth when the Great Pyramid was being built." };

  public String getFact(){

  // The button was clicked so update the fact TextView with a new fact
  String fact = "";
  //Randomly select a fact
  Random randomGenerator = new Random();
  int randomNumber = randomGenerator.nextInt(mFacts.length);
  fact = mFacts[randomNumber];
  
  return fact;
  

  };

}

package com.example.darek.funfacts;

import android.graphics.Color;

import java.util.Random;

/**

• Created by Darek on 13.07.2016. */ public class ColorWheel {

  public String[] mColors = { "#39add1", // light blue "#3079ab", // dark blue "#c25975", // mauve "#e15258", // red "#f9845b", // orange "#838cc7", // lavender "#7d669e", // purple "#53bbb4", // aqua "#51b46d", // green "#e0ab18", // mustard "#637a91", // dark gray "#f092b0", // pink "#b7c0c7" // light gray };

  public int getColor(){ String color;

  Random randomGenerator = new Random();
  int randomNumber = randomGenerator.nextInt(mColors.length);
  color = mColors[randomNumber];
  
  int colorAsInt = Color.parseColor(color);
  
  return colorAsInt;
  

  } }

I found at google that it may have some connection with AndroidManifest.xml so I will add it here aswell: <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.darek.funfacts">

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

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

</manifest>

And styles.xml:

<resources>

<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
</style>

</resources>

Hope that someone is able to help me figure it out. Thanks in advance!

This one's a head-scratcher. Can you try a clean and rebuild (under the Build menu)? Also double-check that your Java are in the main source folder, not either of the test folders.