跟着B站视频做到请求分类数据，但是遇到空指针异常，不知道该咋弄了。去网上搜说是控件id问题，但是还是没有找到答案。求各位佬指点

java.lang.NullPointerException: Attempt to invoke virtual method 'void com.example.taobaounion.presenter.impl.HomePresenterImpl.getCategories()' on a null object reference

    at com.example.taobaounion.ui.fragment.HomeFragment.loadData(HomeFragment.java:35)

    at com.example.taobaounion.base.BaseFragment.onCreateView(BaseFragment.java:19)

    at androidx.fragment.app.Fragment.performCreateView(Fragment.java:2600)

    at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:881)

    at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1238)

    at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1303)

    at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:439)

    at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2079)

    at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1869)

    at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1824)

    at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManagerImpl.java:1727)

    at androidx.fragment.app.FragmentManagerImpl.dispatchStateChange(FragmentManagerImpl.java:2663)

    at androidx.fragment.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManagerImpl.java:2613)

    at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:246)

    at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:542)

    at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:201)

    at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1425)

    at android.app.Activity.performStart(Activity.java:7825)

    at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3294)

    at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:221)

    at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:201)

    at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:173)

    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)

    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)

    at android.os.Handler.dispatchMessage(Handler.java:107)

    at android.os.Looper.loop(Looper.java:214)

    at android.app.ActivityThread.main(ActivityThread.java:7356)

    at java.lang.reflect.Method.invoke(Native Method)

    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)

    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)