For my new app i want to use the Mosby Framework. At the moment i have an activity with two tabs and it works fine for my.
Now i want to implement a new activity with 12 tabs and when i want to switch to a new tab i get a NPE
java.lang.NullPointerException: Presenter returned from getPresenter() is null
at com.hannesdorfmann.mosby.mvp.delegate.MvpInternalDelegate.getPresenter(MvpInternalDelegate.java:76)
at com.hannesdorfmann.mosby.mvp.delegate.MvpInternalDelegate.detachView(MvpInternalDelegate.java:70)
My working activity use the FragmenPagerAdapter. The new Activity should use FragmenStatePagerAdapter. At this point i get a NPE.
Here is my code
//MainActivity
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setupViewPager();
tabLayout.setupWithViewPager(viewPager);
}
@Override
public int getLayout() {
return R.layout.activity_navigation;
}
private void setupViewPager() {
Adapter adapter = new Adapter(getSupportFragmentManager());
DateFormatSymbols dfs = new DateFormatSymbols();
String[] months = dfs.getMonths();
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.MONTH, -12);
for (int i = -12; i <= 12; i++) {
calendar.add(Calendar.MONTH, +1);
adapter.addFragment(months[calendar.get(Calendar.MONTH)]);
}
viewPager.setAdapter(adapter);
//viewPager.setCurrentItem(11);
//viewPager.setOffscreenPageLimit(2);
}
public static class Adapter extends FragmentStatePagerAdapter {
private List<String> fragmentTitles = new ArrayList<>();
public Adapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
return new OverviewFragmentBuilder(1).build();
}
@Override
public int getCount() {
return fragmentTitles.size();
}
@Override
public CharSequence getPageTitle(int position) {
return fragmentTitles.get(position);
}
private void addFragment(String title) {
fragmentTitles.add(title);
}
}
// Fragment
public class OverviewFragment extends MvpFragment<OverviewView, OverviewPresenter>
implements OverviewView {
private OverviewComponent component;
@Arg
public int month;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
FragmentArgs.inject(this);
component = DaggerOverviewComponent
.builder()
.appComponent(((App) getActivity().getApplication()).getAppComponent())
.build();
}
@Override
public OverviewPresenter createPresenter() {
Log.d("wtf", "ever called??");
return component.presenter();
}
My Log "wtf" in the createPresenter is never called... Here a my Dagger-2 component
@ActivityScope
@Component(dependencies = AppComponent.class)
public interface OverviewComponent {
OverviewPresenter presenter();
}
Can anybody help me? I think that the framework works fine and i make a silly mistake... ;D
12-24 15:04:03.800 2547-2547/com.test.testapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.test.testapp, PID: 2547
java.lang.NullPointerException: Presenter returned from getPresenter() is null
at com.hannesdorfmann.mosby.mvp.delegate.MvpInternalDelegate.getPresenter(MvpInternalDelegate.java:76)
at com.hannesdorfmann.mosby.mvp.delegate.MvpInternalDelegate.detachView(MvpInternalDelegate.java:70)
at com.hannesdorfmann.mosby.mvp.delegate.FragmentMvpDelegateImpl.onDestroyView(FragmentMvpDelegateImpl.java:71)
at com.hannesdorfmann.mosby.mvp.MvpFragment.onDestroyView(MvpFragment.java:106)
at android.support.v4.app.Fragment.performDestroyView(Fragment.java:2167)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1141)
at android.support.v4.app.FragmentManagerImpl.removeFragment(FragmentManager.java:1345)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:708)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1613)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:570)
at android.support.v4.app.FragmentStatePagerAdapter.finishUpdate(FragmentStatePagerAdapter.java:163)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1106)
at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:552)
at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:514)
at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:495)
at android.support.design.widget.TabLayout$ViewPagerOnTabSelectedListener.onTabSelected(TabLayout.java:1778)
at android.support.design.widget.TabLayout.selectTab(TabLayout.java:871)
at android.support.design.widget.TabLayout.selectTab(TabLayout.java:841)
at android.support.design.widget.TabLayout$Tab.select(TabLayout.java:1115)
at android.support.design.widget.TabLayout$1.onClick(TabLayout.java:665)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
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)
Just override the onCreateView method and provide a layout. Otherwise the presenter ist null and mosby will throw a NPE for this.