Cannot resolve constructor ArrayAdapter(android.Content.Context, int, java.util.ArrayList<MyObject>)

问题

I know this question has been asked a million times before, but I have tried all of the solutions I can find, and still doesn't work. I have tried calling "this" for context, I have tried getActivity, I have tried getContext(), but nothing seems to work for this fragment in particular. The same code does work in a different fragment tho, which is why I am really confused. Any help appreciated.

My LoginFragment, my issue can be found in setReservations():

public class LoginFragment extends Fragment {
    LoginButton loginButton;
    TextView nameText;
    ProfileTracker mProfileTracker;
    DBHandler dbHandler;
    Context context;
    ArrayList<Reservation> reservations;
    ListView lv;
    Profile fbProfile;

    CallbackManager callbackManager;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.login, container, false);
        callbackManager = CallbackManager.Factory.create();
        dbHandler = new DBHandler(getContext(), null, null, 1);
        context = getActivity();
        loginButton = (LoginButton) view.findViewById(R.id.login_button);
        nameText = (TextView) view.findViewById(R.id.users_name);
        loginButton.setReadPermissions("email");
        setmProfileTracker();
        mProfileTracker.startTracking();
        // If using in a fragment
        loginButton.setFragment(this);
        // Other app specific specialization

        // Callback registration
        loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
            @Override
            public void onSuccess(LoginResult loginResult) {

            }

            @Override
            public void onCancel() {
                // App code
            }

            @Override
            public void onError(FacebookException exception) {
                // App code
            }
        });

        return view;
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        fbProfile = Profile.getCurrentProfile();
        if (fbProfile != null)
        {
            updateUI();
        }
        getActivity().setTitle("My page");
    }


    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        callbackManager.onActivityResult(requestCode,resultCode,data);
    }

    private void setmProfileTracker()
    {
        mProfileTracker = new ProfileTracker() {
            @Override
            protected void onCurrentProfileChanged(Profile profile, Profile profile2) {
                updateUI(); //this is the third piece of code I will discuss below
            }
        };
    }

    private void updateUI() {

        boolean enableButtons = AccessToken.getCurrentAccessToken() != null;
        if (fbProfile == null) {
            fbProfile = Profile.getCurrentProfile();
            Log.e("Profile", "null");
        }
        if (enableButtons && fbProfile != null) {
            Log.e("Access Token", AccessToken.getCurrentAccessToken().toString());
            nameText.setText(fbProfile.getName());
        }
    }

    private void setReservations()
    {
        reservations = dbHandler.userReservationToArrayList(parseLong(fbProfile.getId()));

        lv = (ListView) getView().findViewById(R.id.reservations);

        ArrayAdapter<Review> arrayAdapter = new ArrayAdapter<Review>(
            context,
            android.R.layout.simple_list_item_1,
            reservations);

        lv.setAdapter(arrayAdapter);
    }
}

EDIT: Code format

回答1:

You probably should learn more about generics and type safety.

Your reservations has type ArrayList<Reservation> but you try to create ArrayAdapter<Review> which is wrong. Change it to ArrayAdapter<Reservation>.

回答2:

Your Array Adapter is of Type Review

ArrayAdapter<Review> arrayAdapter 

But Your passing :

 ArrayList<Reservation> reservations
Change it to ArrayAdapter<Reservation>

回答3:

You should pass an array of Review not an array of Reservation. So change your adapter to ArrayAdapter<Reservation>.

Also, at the moment you call the getActivity() method inside the onCreateView() method your Activity is not created yet, which can cause an error. To solve this issue, you should to move this line to your onActivityCreated() :

@Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        context = getActivity();
    }

来源：https://stackoverflow.com/questions/44178693/cannot-resolve-constructor-arrayadapterandroid-content-context-int-java-util