java.lang.RuntimeException: Unable to start activity ComponentInfo:android.view.InflateException

I am trying to create an Image Slider containing 4 images for my application and i've been running into the following errors. I've tried searching and have found similiar titles but the problems are different. This is the logcat:

example.prgguru.com.wallit E/AndroidRuntime: FATAL EXCEPTION: main
Process: example.prgguru.com.wallit, PID: 32048
java.lang.RuntimeException: Unable to start activity ComponentInfo{example.prgguru.com.wallit/example.prgguru.com.wallit.MainActivity}: android.view.InflateException: Binary XML file line #3: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2404)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2464)
at android.app.ActivityThread.access$900(ActivityThread.java:172)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5653)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.view.InflateException: Binary XML file line #3: Error inflating class fragment
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:719)
at android.view.LayoutInflater.inflate(LayoutInflater.java:470)
at android.view.LayoutInflater.inflate(LayoutInflater.java:398)
at android.view.LayoutInflater.inflate(LayoutInflater.java:354)
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:350)
at android.app.Activity.setContentView(Activity.java:2059)
at example.prgguru.com.wallit.MainActivity.onCreate(MainActivity.java:13)
at android.app.Activity.performCreate(Activity.java:5541)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2368)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2464) 
at android.app.ActivityThread.access$900(ActivityThread.java:172) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5653) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107) 
at dalvik.system.NativeStart.main(Native Method) 
Caused by: android.app.Fragment$InstantiationException: Trying to instantiate a class example.prgguru.com.wallit.MainActivityFragment that is not a Fragment
at android.app.Fragment.instantiate(Fragment.java:585)
at android.app.Fragment.instantiate(Fragment.java:561)
at android.app.Activity.onCreateView(Activity.java:5066)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:695)
at android.view.LayoutInflater.inflate(LayoutInflater.java:470) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:398) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:354) 
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:350) 
at android.app.Activity.setContentView(Activity.java:2059) 
at example.prgguru.com.wallit.MainActivity.onCreate(MainActivity.java:13) 
at android.app.Activity.performCreate(Activity.java:5541) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2368) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2464) 
at android.app.ActivityThread.access$900(ActivityThread.java:172) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:146) 
at android.app.ActivityThread.main(ActivityThread.java:5653) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107) 
at dalvik.system.NativeStart.main(Native Method) 
Caused by: java.lang.ClassCastException
at android.app.Fragment.instantiate(Fragment.java:585) 
at android.app.Fragment.instantiate(Fragment.java:561) 
at android.app.Activity.onCreateView(Activity.java:5066) 
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:695) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:470) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:398) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:354) 
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:350) 
at android.app.Activity.setContentView(Activity.java:2059) 
at example.prgguru.com.wallit.MainActivity.onCreate(MainActivity.java:13) 
at android.app.Activity.performCreate(Activity.java:5541) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2368) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2464) 
at android.app.ActivityThread.access$900(ActivityThread.java:172) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:146) 
at android.app.ActivityThread.main(ActivityThread.java:5653) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107) 
at dalvik.system.NativeStart.main(Native Method) 

This is my Main Activity.java:

package example.prgguru.com.wallit;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {

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

This is my activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<fragment
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:name="example.prgguru.com.wallit.MainActivityFragment"
android:id="@+id/fragment"
tools:layout="@layout/fragment_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />

fragment_main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#32383d">
<!-- ViewPager -->

<!-- Footer -->
<android.support.v4.view.ViewPager
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/imageviewPager" />
<include layout="@layout/footer"/>

</FrameLayout>

MainActivityFragment.java

package example.prgguru.com.wallit;

import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivityFragment extends Fragment {
private ViewPager _mViewPager;
private ImageViewPagerAdapter _adapter;
private ImageView _btn1, _btn2, _btn3,_btn4;
public MainActivityFragment() {
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    setUpView();
    setTab();
    onCircleButtonClick();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    return inflater.inflate(R.layout.fragment_main, container, false);
}
private void onCircleButtonClick() {
    _btn1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            _btn1.setImageResource(R.drawable.fill_circle);
            _mViewPager.setCurrentItem(0);
        }
    });
    _btn2.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            _btn2.setImageResource(R.drawable.fill_circle);
            _mViewPager.setCurrentItem(1);
        }
    });
    _btn3.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            _btn3.setImageResource(R.drawable.fill_circle);
            _mViewPager.setCurrentItem(2);
        }
    });
    _btn4.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            _btn4.setImageResource(R.drawable.fill_circle);
            _mViewPager.setCurrentItem(3);
        }
    });
}
private void setUpView() {
    _mViewPager = (ViewPager) getView().findViewById(R.id.imageviewPager);
    _adapter = new ImageViewPagerAdapter(getActivity(),   getFragmentManager());
    _mViewPager.setAdapter(_adapter);
    _mViewPager.setCurrentItem(0);
    initButton();
}
private void setTab() {
    _mViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener()                                                                                                                 {  
        @Override
        public void onPageScrollStateChanged(int position) {
        }
        @Override
        public void onPageScrolled(int arg0, float arg1, int arg2) {
        }
        @Override
        public void onPageSelected(int position) {
            // TODO Auto-generated method stub
            _btn1.setImageResource(R.drawable.holo_circle);
            _btn2.setImageResource(R.drawable.holo_circle);
            _btn3.setImageResource(R.drawable.holo_circle);
            _btn4.setImageResource(R.drawable.holo_circle);
            btnAction(position);
        }
    });
}
private void btnAction(int action) {
    switch (action) {
        case 0:
            _btn1.setImageResource(R.drawable.fill_circle);
            break;
        case 1:
            _btn2.setImageResource(R.drawable.fill_circle);
            break;
        case 2:
            _btn3.setImageResource(R.drawable.fill_circle);
            break;
        case 3:
            _btn4.setImageResource(R.drawable.fill_circle);
            break;
    }
}
private void initButton() {
    _btn1 = (ImageView) getView().findViewById(R.id.btn1);
    _btn1.setImageResource(R.drawable.fill_circle);
    _btn2 = (ImageView) getView().findViewById(R.id.btn2);
    _btn3 = (ImageView) getView().findViewById(R.id.btn3);
    _btn4 = (ImageView) getView().findViewById(R.id.btn4);
}
private void setButton(Button btn, String text, int h, int w) {
    btn.setWidth(w);
    btn.setHeight(h);
    btn.setText(text);
}
}