FragmentPagerAdapter - unable to resolve superclass

问题

I`m trying to use FragmentPagerAdapter but when trying to run it- there is an error:

02-22 22:48:53.328: W/dalvikvm(830): Unable to resolve superclass of Linfo/androidhive/tabsswipe/SlideActivity$FragmentPagerAdapter; (94) 02-22 22:48:53.328: W/dalvikvm(830): Link of class 'Linfo/androidhive/tabsswipe/SlideActivity$FragmentPagerAdapter;' failed 02-22 22:48:53.328: E/dalvikvm(830): Could not find class 'info.androidhive.tabsswipe.SlideActivity$FragmentPagerAdapter', referenced from method info.androidhive.tabsswipe.SlideActivity.onCreate

my code:

package info.androidhive.tabsswipe;


import info.androidhive.tabsswipe.SlideFragment;
import android.app.Fragment;
import android.app.FragmentManager;
import android.os.Bundle;
import android.support.v13.app.FragmentStatePagerAdapter;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.Menu;
import android.view.MenuItem;


public class SlideActivity extends FragmentActivity {

    private static final int NUM_PAGES = 5;


    private ViewPager mPager;


    private PagerAdapter mPagerAdapter;

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

        // Instantiate a ViewPager and a PagerAdapter.
        mPager = (ViewPager) findViewById(R.id.pager);
        mPagerAdapter = new FragmentPagerAdapter(getFragmentManager());
        mPager.setAdapter(mPagerAdapter);
        mPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
            @Override
            public void onPageSelected(int position) {

                invalidateOptionsMenu();
            }
        });
    } 

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);
        getMenuInflater().inflate(R.menu.activity_screen_slide, menu); 

        menu.findItem(R.id.action_previous).setEnabled(mPager.getCurrentItem() > 0);


        MenuItem item = menu.add(Menu.NONE, R.id.action_next, Menu.NONE,
                (mPager.getCurrentItem() == mPagerAdapter.getCount() - 1)
                        ? R.string.action_finish
                        : R.string.action_next);
        item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM | MenuItem.SHOW_AS_ACTION_WITH_TEXT);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {


            case R.id.action_previous:

                mPager.setCurrentItem(mPager.getCurrentItem() - 1);
                return true;

            case R.id.action_next:

                // will do nothing.
                mPager.setCurrentItem(mPager.getCurrentItem() + 1);
                return true;
        }

        return super.onOptionsItemSelected(item);
    }


    public static class FragmentPagerAdapter extends FragmentStatePagerAdapter {
        public FragmentPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            return SlideFragment.create(position);
        }

        @Override
        public int getCount() {
            return NUM_PAGES;
        }
    }
}

already tried to build path, clean and import android.support.v13.app.FragmentPagerAdapter;

There is the SlideFragment class if it could help...

package info.androidhive.tabsswipe;

import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/**
 * A fragment representing a single step in a wizard. The fragment shows a dummy title indicating
 * the page number, along with some dummy text.
 *
 * <p>This class is used by the {@link CardFlipActivity} and {@link
 * ScreenSlideActivity} samples.</p>
 */
public class SlideFragment extends Fragment {
    /**
     * The argument key for the page number this fragment represents.
     */
    public static final String ARG_PAGE = "page";

    /**
     * The fragment's page number, which is set to the argument value for {@link #ARG_PAGE}.
     */
    private int mPageNumber;

    /**
     * Factory method for this fragment class. Constructs a new fragment for the given page number.
     */
    public static SlideFragment create(int pageNumber) {
        SlideFragment fragment = new SlideFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_PAGE, pageNumber);
        fragment.setArguments(args);
        return fragment;
    }

    public SlideFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mPageNumber = getArguments().getInt(ARG_PAGE);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        // Inflate the layout containing a title and body text.
        ViewGroup rootView = (ViewGroup) inflater
                .inflate(R.layout.fragment_slide, container, false); 

        // Set the title view to show the page number.


        return rootView;
    }

    /**
     * Returns the page number represented by this fragment object.
     */
    public int getPageNumber() {
        return mPageNumber;
    }
}

thanks.

回答1:

You are using the FragmentStatePagerAdapter from v13 instead of v4. Thats the problem. In version 13 the FragmentManager that is used is the one on android 3.5 and higher, In version 4 of the support library the FragmentManager is the supportFragmentManager.

回答2:

If you switch to v4, it should work by just adding this constructor on your FragmentPagerAdapter class:

/** Constructor of the class */
public FragmentPagerAdapter(FragmentManager fragmentManager) {
    super(fragmentManager);
}

来源：https://stackoverflow.com/questions/21961762/fragmentpageradapter-unable-to-resolve-superclass