Android Studio Programming

Second public class error, what can I do ???

If anyone knows please say.

Thank you.

package com.example.hsantos_98.artofthefire;

import android.app.Fragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.ViewFlipper;

public class ThirdFragment extends Fragment {

View myView;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    myView = inflater.inflate(R.layout.third_layout, container, false);
    return myView;
}

public class ThirdFragment extends AppCompatActivity { 
    Animation fade_in, fade_out;
    ViewFlipper viewFlipper;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_activity);
        viewFlipper = (ViewFlipper)  this.findViewById(R.id.bckgrndViewFlipper1);
        fade_in = AnimationUtils.loadAnimation(this,
                android.R.anim.fade_in);
        fade_out = AnimationUtils.loadAnimation(this,
                android.R.anim.fade_out);
        viewFlipper.setInAnimation(fade_in);
        viewFlipper.setOutAnimation(fade_out);

        viewFlipper.setAutoStart(true);
        viewFlipper.setFlipInterval(5000);
        viewFlipper.startFlipping();
    }

}