java - FragmentPagerAdapter - 无法解析父类(super class)

Question

我正在尝试使用 FragmentPagerAdapter，但在尝试运行它时出现错误:

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

我的代码:

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;
        }
    }
}

已经尝试构建路径、清理并导入 android.support.v13.app.FragmentPagerAdapter;

如果有帮助的话，有 SlideFragment 类...

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;
    }
}

谢谢。

Answer 1

您使用的是 v13 中的 FragmentStatePagerAdapter，而不是 v4。那就是问题所在。在版本 13 中，使用的 FragmentManager 是 android 3.5 及更高版本上的 FragmentManager。在支持库的版本 4 中，FragmentManager 是 supportFragmentManager。