The method setAdapter... error.

myPager.setAdapter(adapter);

package com.example.gymbuddy;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.os.Parcelable;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;

public class Upperbody extends Activity {

	@Override
	public void onCreate(Bundle savedInstanceState) {
	    super.onCreate(savedInstanceState);
	    setContentView(R.layout.activity_upperbody);
	    
	    MyPagerAdapter adapter = new MyPagerAdapter();
	    ViewPager myPager = (ViewPager) findViewById(R.id.myfivepanelpager);
	    myPager.setAdapter(adapter);
	    myPager.setCurrentItem(2); }
	
	public class MyPagerAdapter extends Activity {
		 
        public int getCount() {
            return 9;
        }
 
        public Object instantiateItem(View collection, int position) {
 
            LayoutInflater inflater = (LayoutInflater) collection.getContext()
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
 
            int resId = 0;
            switch (position) {
            case 0:
                resId = R.layout.upper0;
                break;
            case 1:
                resId = R.layout.upper1;
                break;
            case 2:
                resId = R.layout.upper2;
                break;
            case 3:
                resId = R.layout.upper3;
                break;
            case 4:
                resId = R.layout.upper4;
                break;
            case 5:
            	resId = R.layout.upper5;
            	break;
            case 6:
            	resId = R.layout.upper6;
            	break;
            case 7:
            	resId = R.layout.upper7;
            	break;
            case 8:
            	resId = R.layout.upper8;
            	break; }
 
            View view = inflater.inflate(resId, null);
 
            ((ViewPager) collection).addView(view, 0);
 
            return view; }
        
        public void destroyItem(View arg0, int arg1, Object arg2) {
            ((ViewPager) arg0).removeView((View) arg2); }
        
        public boolean isViewFromObject(View arg0, Object arg1) {
            return arg0 == ((View) arg1); }
        
        public Parcelable saveState() {
            return null; }
        
	}
	
}