android - 不兼容类型 : Fragment cannot be converted to NavigationDrawerFragment

Question

我一直在开发一个使用 API 14 的应用程序，但我不得不降级到 API 10。该应用程序有 fragment 和 Activity fragment ，我已经导入了库并使用了 getFragmentSupportManager 因为它是 v4。但是，我有以下错误:

我从一开始就使用 API 10 创建了一个带有抽屉布局和 fragment 的虚拟应用程序，它在 MyActivity 文件中有相同的行，这不是错误。这是我的代码:

package az.test2;

import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.view.Gravity;


public class MyActivity extends ActionBarActivity
    implements NavigationDrawerFragment.NavigationDrawerCallbacks {

    /**
     * Fragment managing the behaviors, interactions and presentation of the navigation drawer.
     */
    private NavigationDrawerFragment mNavigationDrawerFragment;

    /**
     * Used to store the last screen title. For use in {@link #restoreActionBar()}.
     */
    private CharSequence mTitle;

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

        mNavigationDrawerFragment = (NavigationDrawerFragment)
           getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
        mTitle = getTitle();

        // Set up the drawer.
        mNavigationDrawerFragment.setUp(
            R.id.navigation_drawer,
            (DrawerLayout) findViewById(R.id.drawer_layout));

    }

    @Override
    public void onNavigationDrawerItemSelected(int position) {
        // update the main content by replacing fragments
        android.support.v4.app.FragmentManager lolo;

        FragmentManager FM = getSupportFragmentManager();
        FragAV fav = new FragAV();
        FragW fw = new FragW();

        switch (position){
            case 0:
                FM.beginTransaction()
                    .replace(R.id.container, fav).commit();
                break;
            case 1:
                FM.beginTransaction()
                    .replace(R.id.container, fw).commit();
                break;
            case 2: break;
        }


        //FM.beginTransaction().replace(R.id.container, PlaceholderFragment.newInstance(position + 1)).commit();

    }

    public void onSectionAttached(int number) {
        switch (number) {
            case 1:
                mTitle = getString(R.string.title_section1);
                break;
            case 2:
                mTitle = getString(R.string.title_section2);
                break;
            case 3:
                mTitle = getString(R.string.title_section3);
                break;
        }
    }

    public void restoreActionBar() {
        ActionBar actionBar = getSupportActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
        actionBar.setDisplayShowTitleEnabled(true);
        actionBar.setTitle(mTitle);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        if (!mNavigationDrawerFragment.isDrawerOpen()) {
            // Only show items in the action bar relevant to this screen
            // if the drawer is not showing. Otherwise, let the drawer
            // decide what to show in the action bar.
            getMenuInflater().inflate(R.menu.my, menu);
            restoreActionBar();

            return true;
        }
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        private static final String ARG_SECTION_NUMBER = "section_number";

        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_my, container, false);
            return rootView;
        }

        @Override
        public void onAttach(Activity activity) {
            super.onAttach(activity);
            ((MyActivity) activity).onSectionAttached(
                getArguments().getInt(ARG_SECTION_NUMBER));
        }
    }
}

我已经尽我所能，但这个错误似乎很少见。任何帮助将不胜感激。

Answer 1

使用支持包时，您的 fragment 应该扩展 android.support.v4.app.Fragment 而不是常规的 fragment 类。