[英]Class cast exception: fragment 1 cannot be cast to fragment 2
我現在有一個項目,需要使用2個片段。 在我的mainActivity
內部,我從兩個片段中調用了兩個方法來初始化其適配器。 我現在面臨的問題是,當我對第二個片段調用該方法時,我得到一個類強制轉換異常,該異常表示我的片段1無法強制轉換為片段2。
我正在導入正確的庫import android.support.v4.app.Fragment
所以我不知道為什么會收到錯誤。
這是我的活動的一部分,在其中定義片段:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//toolbar = (Toolbar) findViewById(R.id.toolbar);
//setSupportActionBar(toolbar);
token = SharedPrefsHelper.getString(getApplicationContext(), Constants.TOKEN);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
SendNetworkRequest(0);
SendNetworkRequest(1);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new InternsFragment(), "Internos");
adapter.addFragment(new ExternsFragment(), "Externos");
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
@Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
@Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
@Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
這是當我從Activity中的第一個Fragment調用方法時:
if (listUsers != null && !listUsers.isEmpty()) {
ExternsFragment fragment = (ExternsFragment) getSupportFragmentManager().findFragmentById(R.id.viewpager);
fragment.initAdapter(listUsers);
}
這是當我從Activity中的第二個Fragment調用方法時:
if (!response.body().isEmpty()) {
listTeams = response.body();
InternsFragment fragment = (InternsFragment) getSupportFragmentManager().findFragmentById(R.id.viewpager);
fragment.initAdapter();
for ( int j = 0; j < listTeams.size(); j ++) {
System.out.println(listTeams.get(j).getName());
}
}
這是第一個片段的代碼:
public class ExternsFragment extends Fragment {
//@BindView(R.id.recycler_view) RecyclerView recyclerView;
private TeamAdapter teamAdapter;
private RecyclerView recyclerView;
public ExternsFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView = inflater.inflate(R.layout.fragment_externs, container, false);
recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
return rootView;
}
public void initAdapter(List<UserProject> userList) {
teamAdapter = new TeamAdapter(getActivity(), userList);
recyclerView.setAdapter(teamAdapter);
}
}
這是第二個:
public class InternsFragment extends Fragment{
private RecyclerView recyclerView;
List<ListItem> consolidatedList = new ArrayList<>();
private GroupAdapter adapter;
public InternsFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView = inflater.inflate(R.layout.fragment_interns, container, false);
recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
return rootView;
}
private HashMap<String, List<UserProject>> groupDataIntoHashMap(List<UserProject> listOfPojosOfJsonArray) {
HashMap<String, List<UserProject>> groupedHashMap = new HashMap<>();
for (UserProject pojoOfJsonArray : listOfPojosOfJsonArray) {
String hashMapKey = pojoOfJsonArray.getTeamId();
if (groupedHashMap.containsKey(hashMapKey)) {
// The key is already in the HashMap; add the pojo object
// against the existing key.
groupedHashMap.get(hashMapKey).add(pojoOfJsonArray);
} else {
// The key is not there in the HashMap; create a new key-value pair
List<UserProject> list = new ArrayList<>();
list.add(pojoOfJsonArray);
groupedHashMap.put(hashMapKey, list);
}
}
return groupedHashMap;
}
public void initAdapter() {
HashMap<String, List<UserProject>> groupedHashMap = groupDataIntoHashMap(ActivityTeams.listUsers);
for (String date : groupedHashMap.keySet()) {
TeamItem dateItem = new TeamItem();
dateItem.setTeam(date);
consolidatedList.add(dateItem);
for (UserProject pojoOfJsonArray : groupedHashMap.get(date)) {
GeneralItem generalItem = new GeneralItem();
generalItem.setPojoOfJsonArray(pojoOfJsonArray);//setBookingDataTabs(bookingDataTabs);
consolidatedList.add(generalItem);
}
}
adapter = new GroupAdapter(getActivity(), consolidatedList);
LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
recyclerView.setLayoutManager(layoutManager);
recyclerView.setAdapter(adapter);
}
}
將片段作為活動的類變量。
InternsFragment mInternsFragment;
ExternsFragment mExternsFragment;
//inside oncreate
mInternsFragment = new InternsFragment ();
mExternsFragment = new ExternsFragment ();
adapter.addFragment( mInternsFragment, "Internos" );
adapter.addFragment( mExternsFragment, "Externos" );
然后直接在活動中的任何地方使用它們。
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