您好，我尝试将 Presenter 对象初始化到我的片段中，但它抛出 ClassCastException
E/AndroidRuntime: FATAL EXCEPTION: main Process: com.varshaawebteam.tp_comment_mvp, PID: 22672
java.lang.ClassCastException: com.varshaawebteam.tp_comment_mvp.HomeActivity.HomeActivity cannot be cast to com.varshaawebteam.tp_comment_mvp.TournamentListActvity.Presenter.ITournamentPresenter
at com.varshaawebteam.tp_comment_mvp.TournamentListActvity.TournamentListFragment.onCreateView(TournamentListFragment.java:51)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:2192)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1299)
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1528)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1595)
at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:758)
at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2363)
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2149)
at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2103)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2013)
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:710)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
HomeActivity.java（主类）
public class HomeActivity extends AppCompatActivity implements HomeViewInterface, IHomePresenter {
SlidingPaneLayout slide_pane;
HomePresenter homePresenter;
private Toolbar mToolbar;
SharedPreferences pref_login;
Gson gson;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
slide_pane = (SlidingPaneLayout) findViewById(R.id.slide_pane);
homePresenter = new HomePresenter(this, this, this);
mToolbar = (Toolbar) findViewById(R.id.toolbar);
if (mToolbar != null) {
setSupportActionBar(mToolbar);
}
mToolbar.setTitle("My Games");
pref_login = getSharedPreferences(Pref_Data.PREF_LOGIN, MODE_PRIVATE);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
gson = new Gson();
mToolbar.setNavigationIcon(R.drawable.ic_drawer);
mToolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (slide_pane.isOpen()) {
slide_pane.closePane();
} else {
slide_pane.openPane();
}
}
});
slide_pane = (SlidingPaneLayout) findViewById(R.id.slide_pane);
drawer_fragment menu = new drawer_fragment();
getSupportFragmentManager().beginTransaction().add(R.id.ll_drawer, menu).commit();
homePresenter.getdrawerselection(0);
}
@Override
public void getdrawerselection(int i) {
}
@Override
public void openmygamefragment() {
}
@Override
public void opentournamentfragment() {
}
@Override
public void setdrawerselection(int i) {
try {
slide_pane.closePane();
} catch (Exception e) {
e.printStackTrace();
}
if (i == 0) {
setTitle("My Game");
homePresenter.openmygamefragment();
Log.e("Game:-", "Game");
} else if (i == 1) {
setTitle("Tournament List");
Log.e("Tournament:-", "Tournament");
homePresenter.opentournamentfragment();
} else if (i == 2) {
Toast.makeText(this, "logout", Toast.LENGTH_SHORT).show();
}
}
@Override
public void setmygamefragment() {
}
@Override
public void settournamnetfragment() {
TournamentListFragment tournament = new TournamentListFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.fragment_container, tournament, "frag1")
.addToBackStack("2")
.commit();
}
}
TournamentPresenter.java（演示者）
public class TournamentPresenter implements ITournamentPresenter {
private final Services services;
private final android.content.Context context;
private final ITournamentPresenter mListener;
private final ITournamentView tournamentview;
private Dialog progressDialog;
ArrayList<TournamentRes_data> tournamentResDatas = new ArrayList<TournamentRes_data>();
public TournamentPresenter(ITournamentPresenter listener, ITournamentView tournamentView, Context context) {
this.mListener = listener;
this.context = context;
this.services = new Services();
this.tournamentview = tournamentView;
}
@Override
public void tournamentready(Response<TournamentRes> response) {
}
public void gettournamentlistcall(double lat, double longii) {
progressDialog = new Dialog(context);
progressDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
progressDialog.getWindow().setBackgroundDrawable(new ColorDrawable(android.graphics.Color.TRANSPARENT));
progressDialog.setContentView(R.layout.progress_bar_custom);
progressDialog.setCancelable(true);
progressDialog.show();
services.getAPI()
.getList_Results(lat, longii)
.enqueue(new Callback<TournamentRes>() {
@Override
public void onResponse(Call<TournamentRes> call, Response<TournamentRes> response) {
if (!response.body().getDATA().isEmpty()) {
mListener.tournamentready(response);
}
}
@Override
public void onFailure(Call<TournamentRes> call, Throwable t) {
call.cancel();
progressDialog.dismiss();
Toast.makeText(context, "Server Error", Toast.LENGTH_SHORT).show();
}
});
}
}
最后这是我的片段，我收到强制转换异常错误
TournamentListFragment.java (查看)
public class TournamentListFragment extends Fragment implements ITournamentPresenter, ITournamentView {
GPSTracker gps;
ListView lvTournaments;
private Dialog progressDialog;
TextView tvNoData;
Tournament_List_Adapter tournament_list_adapter;
TournamentPresenter tournamnetpresenter;
ArrayList<TournamentRes_data> tournamentResDatas = new ArrayList<TournamentRes_data>();
Context context;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final View rootView = inflater.inflate(R.layout.frag_tournament, container, false);
gps = new GPSTracker(getActivity());
context = getActivity();
lvTournaments = (ListView) rootView.findViewById(R.id.listview);
tvNoData = (TextView) rootView.findViewById(R.id.listview_data);
tournamnetpresenter = new TournamentPresenter((ITournamentPresenter) getActivity(), (ITournamentView) getActivity(), getActivity());
Toast.makeText(getActivity(), "Tournament", Toast.LENGTH_SHORT).show();
if (gps.canGetLocation()) {
tournamnetpresenter.gettournamentlistcall(gps.getLatitude(), gps.getLongitude());
} else {
gps.showSettingsAlert();
}
return rootView;
}
@Override
public void tournamentready(Response<TournamentRes> response) {
if (!response.body().getDATA().isEmpty()) {
tournamentResDatas.addAll(response.body().getDATA());
if (tournamentResDatas.size() == 0) {
tvNoData.setVisibility(View.VISIBLE);
tvNoData.bringToFront();
} else {
tvNoData.setVisibility(View.GONE);
}
if (tournament_list_adapter != null) {
lvTournaments.setAdapter(tournament_list_adapter);
} else {
tournament_list_adapter = new Tournament_List_Adapter(getActivity(), tournamentResDatas);
lvTournaments.setAdapter(tournament_list_adapter);
}
}
}
@Override
public void getlistready() {
}
}
请查看我的代码并帮助我解决问题。我的问题很简单，我无法在 Fragment 类中初始化 Presenter。