尝试调用虚方法'java.util.Iterator java.util.ArrayList

Question

我正在开发一个Android应用程序来获取数据。它崩溃了，我得到一个NullPointerException。任何人都可以帮我编辑我的代码/列出我的错误吗？

这是一种崩溃的方法       private void ClaimCategory（）{

    final ArrayList<ClaimModel> claimModels = new ArrayList<ClaimModel>();
    claimModels.equals(AareonLocataireManager.getInstance().getClaims());

    ArrayList<String> alist = new ArrayList<String>();

    claimCategoryModel = new ArrayList<>();


    alist.add(getActivity().getString(R.string.Mob_my_claim_category));
    claimCategoryModel = AareonLocataireManager.getInstance().getClaimCategoryModelsObject();
    // Création d'une ListIterator
    ListIterator itr = claimCategoryModel.listIterator();
    int i = 0;
    // Afficher le contenu à l'aide de 'ListIterator'

    while (itr.hasNext()) {

        if (i == 2) break;
        alist.add(
                claimCategoryModel.get(i).getLIBELLE());
        i++;
    }


    ArrayAdapter<String> catAdapter = initSpinnerValues(alist);

    catAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    categoriesSpinner.setAdapter(catAdapter);


}

这是我的logcat

11-09 19:02:10.646 30715-30715/fr.aareon.saumur E/AndroidRuntime: FATAL EXCEPTION: main Process: fr.aareon.saumur, PID: 30715
java.lang.NullPointerException: Attempt to invoke virtual method 'java.util.ListIterator java.util.ArrayList.listIterator()' on a null object reference
  at fr.aareon.saumur.fragments.AddClaimFragment.ClaimCategory(AddClaimFragment.java:519)
  at fr.aareon.saumur.fragments.AddClaimFragment.afterViews(AddClaimFragment.java:235)
  at fr.aareon.saumur.fragments.AddClaimFragment_.onViewChanged(AddClaimFragment_.java:144)
  at org.androidannotations.api.view.OnViewChangedNotifier.notifyViewChanged(OnViewChangedNotifier.java:41)
  at fr.aareon.saumur.fragments.AddClaimFragment_.onViewCreated(AddClaimFragment_.java:101)
  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1314)
  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:757)
  at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2355)
  at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2146)
  at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2098)
  at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2008)
  at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:763)
  at fr.aareon.saumur.activities.DashboardActivity.changeFragment(DashboardActivity.java:171)
  at fr.aareon.saumur.activities.DashboardActivity$3.run(DashboardActivity.java:185)
  at android.os.Handler.handleCallback(Handler.java:751)
  at android.os.Handler.dispatchMessage(Handler.java:95)
  at android.os.Looper.loop(Looper.java:154)
  at android.app.ActivityThread.main(ActivityThread.java:6121)
  at java.lang.reflect.Method.invoke(Native Method)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:889)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:779)