android - スワイプ機能が動作しない

Question

Android アプリケーションでスワイプを実装する方法を示すオンラインのチュートリアルに従いましたが、デバイスでテストしたところスワイプしませんでした。

私のメインクラスは次のようになります。

public class MainActivity extends FragmentActivity implements OnClickListener{

    /**
     * The {@link android.support.v4.view.PagerAdapter} that will provide
     * fragments for each of the sections. We use a
     * {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
     * will keep every loaded fragment in memory. If this becomes too memory
     * intensive, it may be best to switch to a
     * {@link android.support.v4.app.FragmentStatePagerAdapter}.
     */
    SectionsPagerAdapter mSectionsPagerAdapter;

    /**
     * The {@link ViewPager} that will host the section contents.
     */
    ViewPager mViewPager;
    EditText offsetLength,offsetDepth,ductDepth;
    Button calculate;
    //DemoCollectionPagerAdapter mDemoCollectionPagerAdapter;

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

        final Intent intent1=new Intent(this,AboutActivity.class);
        final Intent intent2=new Intent(this,MainActivity.class);
        offsetLength = (EditText)findViewById(R.id.offLength);
        offsetDepth = (EditText)findViewById(R.id.offDepth);
        ductDepth = (EditText)findViewById(R.id.ductDepth);
        calculate = (Button)findViewById(R.id.calc);
        calculate.setOnClickListener(this);

        final ViewGroup actionBarLayout = (ViewGroup) getLayoutInflater().inflate(R.layout.a,null);

        // Create the adapter that will return a fragment for each of the three
        // primary sections of the app.
        mSectionsPagerAdapter = new SectionsPagerAdapter(
                getSupportFragmentManager());

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.pager);
        mViewPager.setAdapter(mSectionsPagerAdapter);

    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub

        try {

            String getoffsetlength = offsetLength.getText().toString(); 
            String getoffsetdepth = offsetDepth.getText().toString(); 
            String getductdepth = ductDepth.getText().toString(); 

            double tri1,tri2;
            double marking1,marking2,marking3;

            double off1 = Double.parseDouble(getoffsetlength);
            double off2 = Double.parseDouble(getoffsetdepth);
            double off3 = Double.parseDouble(getductdepth);

            Intent myIntent = new Intent(MainActivity.this, CalcResult.class);
            myIntent.putExtra("number1", marking1);
            myIntent.putExtra("number2", marking2);
            myIntent.putExtra("number3", marking3);
            startActivity(myIntent);

            Toast.makeText(getBaseContext(), "Calculating!", Toast.LENGTH_SHORT).show(); 


        } catch (NumberFormatException e) {
            // TODO: handle exception
            System.out.println("Must enter a numeric value!");


        }
//      
    }

    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);

        return true;
    }

    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            // getItem is called to instantiate the fragment for the given page.
            // Return a DummySectionFragment (defined as a static inner class
            // below) with the page number as its lone argument.
            Fragment fragment = new DummySectionFragment();
            Bundle args = new Bundle();
            args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
            fragment.setArguments(args);
            return fragment;
        }

        @Override
        public int getCount() {
            // Show 3 total pages.
            return 3;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            Locale l = Locale.getDefault();
            switch (position) {
            case 0:
                return getString(R.string.title_section1).toUpperCase(l);
            case 1:
                return getString(R.string.title_section2).toUpperCase(l);
            case 2:
                return getString(R.string.title_section3).toUpperCase(l);
            }
            return null;
        }
    }

    /**
     * A dummy fragment representing a section of the app, but that simply
     * displays dummy text.
     */
    public static class DummySectionFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        public static final String ARG_SECTION_NUMBER = "section_number";

        public DummySectionFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main_dummy,
                    container, false);
            TextView dummyTextView = (TextView) rootView
                    .findViewById(R.id.section_label);
            dummyTextView.setText(Integer.toString(getArguments().getInt(
                    ARG_SECTION_NUMBER)));
            return rootView;
        }
    }

}