findViewById() isn't working!

You could try and clean the project. I had the same problem. And if that doesn't work, try rebooting your computer.

Here is my code Kourosh Raeen :

package com.example.diaded.funfactsproject;

import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.widget.Button; import android.widget.TextView;

public abstract class FunFacts extends AppCompatActivity { //Declaring our view variables private TextView mFactTextView; private Button mShowFactsButton;

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

}
//Assign the views from the layout file to the private fields declared
mFactTextView = (TextView)findViewById(R.id.factTextView);

I'm not sure if your problem is related to this, but how come you've declared the class as abstract? Also, in the videos the class is named FunFactsActivity. Of course, you can name it anything you want, but make sure it is consistent with the rest of your code and is not a typo.