我想制作一个带有导航抽屉的应用程序。问题是，一旦我启动模拟器，我得到一个警告:
"错误:(63,77)错误:不兼容的类型:FaecherFragment不能转换为Fragment".
MainActivity中的错误显示:
"第二个参数类型错误。发现:´com.example.android.test6。FaecherFragment '， required ' android.support.v4.app.Fragment ' "
我已经发现了一些类似的问题，这些问题都可以通过从` android.app.support.v4.app更改import语句来解决。Fragment ' to ' android.app。碎片或相反的方式……遗憾的是，这对我不起作用……我从字面上尝试了这两者的每一个组合在每一个片段或类我所做的，但它不会工作。
我也试图改变我的片段，所以它扩展' android.support.v4.app.Fragment '…这也不行
我是android的新手，所以也许这只是初学者的错误…无论如何，我真的希望有人能帮助我!!
MainActivity:
package com.example.android.test6;
import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
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;
public class MainActivity extends AppCompatActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks, FaecherFragment.OnFragmentInteractionListener {
/**
* 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_main);
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
FragmentManager fragmentManager = getSupportFragmentManager();
switch (position) {
case 0:
fragmentManager.beginTransaction()
.replace(R.id.container, PlaceholderFragment.newInstance(position + 1))
.commit();
break;
case 1:
fragmentManager.beginTransaction()
.replace(R.id.container, PlaceholderFragment.newInstance(position + 1))
.commit();
break;
case 2:
fragmentManager.beginTransaction()
.replace(R.id.container, FaecherFragment.newInstance("a","b"))
.commit();
break;
}
}
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.main, 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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onFragmentInteraction(String id) {
}
/**
* 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_main, container, false);
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((MainActivity) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
}
FaecherFragment:
package com.example.android.test6;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.app.ListFragment;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.List;
/**
* A fragment representing a list of Items.
* <p/>
* <p/>
* Activities containing this fragment MUST implement the {@linkOnFragmentInteractionListener}
* interface.
*/
public class FaecherFragment extends ListFragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
// TODO: Rename and change types of parameters
public static FaecherFragment newInstance(String param1, String param2) {
FaecherFragment fragment = new FaecherFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
/**
* Mandatory empty constructor for the fragment manager to instantiate the
* fragment (e.g. upon screen orientation changes).
*/
public FaecherFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
// TODO: replace hardcoded Faecher
List<Faecher> faecherList = new ArrayList<Faecher>();
faecherList.add(new Faecher("Mathe"));
faecherList.add(new Faecher("Englisch"));
faecherList.add(new Faecher("Sport"));
setListAdapter(new ArrayAdapter<Faecher>(getActivity(),
android.R.layout.simple_list_item_1, android.R.id.text1, faecherList));
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mListener = (OnFragmentInteractionListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
super.onListItemClick(l, v, position, id);
//to start a new activity we have to declare an intent, this intent needs a context (the
//activity in which we are) and the class that we want to pass the intent into
Intent intent = new Intent(getActivity(), FaecherDetailsActivity.class);
//now we take the clicked listitem from our listView l and store it inside a variable
String title = l.getItemAtPosition(position).toString();
//we give this variable to the intent (as an extra)
intent.putExtra("value_title", title);
//now we start the activity
getActivity().startActivity(intent);
if (null != mListener) {
// Notify the active callbacks interface (the activity, if the
// fragment is attached to one) that an item has been selected.
//mListener.onFragmentInteraction(DummyContent.ITEMS.get(position).id);
}
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p/>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
public void onFragmentInteraction(String id);
}
}
你有
import android.app.ListFragment;
public class FaecherFragment extends ListFragment
更改import以支持列表片段
导入错误的类。你必须从支持库中导入片段:
import android.support.v4.app.ListFragment;
您的FaecherFragment扩展了ListFragment。ListFragment是Fragment的延伸。此Fragment与support.v4.app.FragmentManager不兼容。
FaecherFragment扩展 support.v4.app.ListFragment 扩展support.v4.app.Fragment