Fragment Code:

public class ResultsFragment extends Fragment { private String id; private RecyclerView recyclerView; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(R.layout.fragment_results, container, false); recyclerView = (RecyclerView) view.findViewById(R.id.recycler_view_all); ActivityFragments activityFragments = (ActivityFragments) getActivity(); id = activityFragments.getMyData(); // AllResultPresenter allResultPresenter = new AllResultPresenter(id,ResultsFragment.this); return view; } @Override public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { // super.onViewCreated(view, savedInstanceState); final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity()); recyclerView.setHasFixedSize(true); // there is Error; null recyclerView.setLayoutManager(linearLayoutManager); AllResultPresenter allResultPresenter = new AllResultPresenter(id,ResultsFragment.this); } public void showAllResult(ArrayList<Result> allResultResponses) { recyclerView.setAdapter(new AllResultsAdapter(this, allResultResponses)); } }

Activity Code:

 public class ActivityFragments extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener { private String mId; Fragment fragment; Class fragmentClass; FragmentManager fragmentManager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_exam); Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); fragment = null; fragmentClass = null; fragmentManager = getSupportFragmentManager(); fragmentClass = HelloFragment.class; try { fragment = (Fragment) fragmentClass.newInstance(); } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } fragmentManager.beginTransaction().add(R.id.container, fragment).commit(); // // Intent kek = getIntent(); // String kek1 = kek.getStringExtra("ExamFragment"); // if(kek1 != null) { // Log.d("Please", kek1); // } /* if(kek1 == null){ }else { fragmentClass = ExamFragment.class; try { fragment = (Fragment) fragmentClass.newInstance(); } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } fragmentManager.beginTransaction().replace(R.id.container,fragment).commit(); } */ Intent intent = getIntent(); mId = intent.getStringExtra("id"); //work Log.d("qwerty",mId); FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab); fab.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Snackbar.make(view, mId, Snackbar.LENGTH_LONG) .setAction("Action", null).show(); } }); DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); ActionBarDrawerToggle toggle = new ActionBarDrawerToggle( this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close); drawer.setDrawerListener(toggle); toggle.syncState(); NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view); navigationView.setNavigationItemSelectedListener(this); } @Override protected void onNewIntent(Intent intent) { super.onNewIntent(intent); String testMeNeed = intent.getStringExtra("ExamFragment"); if(testMeNeed.equals("ExamFragment")){ Log.d("MyFirstFragment", testMeNeed); fragmentClass = ExamFragment.class; try { fragment = (Fragment) fragmentClass.newInstance(); } catch (Exception e) { e.printStackTrace(); } fragmentManager.beginTransaction().replace(R.id.container, fragment).commit(); } } @Override public void onBackPressed() { DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); if (drawer.isDrawerOpen(GravityCompat.START)) { drawer.closeDrawer(GravityCompat.START); } else { super.onBackPressed(); } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.exam, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); //noinspection SimplifiableIfStatement if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } @SuppressWarnings("StatementWithEmptyBody") @Override public boolean onNavigationItemSelected(MenuItem item) { // Handle navigation view item clicks here. int id = item.getItemId(); /* fragment = null; fragmentClass = null; if(fragmentClass == null) { fragmentClass = HelloFragment.class; } */ if (id == R.id.nav_camera) { fragmentClass = ExamFragment.class; } else if (id == R.id.nav_gallery) { fragmentClass = ResultsFragment.class; } else if (id == R.id.nav_slideshow) { fragmentClass = RemindersFragment.class; } else if (id == R.id.nav_share) { } // if(fragment == null) { try { fragment = (Fragment) fragmentClass.newInstance(); } catch (Exception e) { e.printStackTrace(); } // } // Вставляем фрагмент, заменяя текущий фрагмент // fragmentManager = getSupportFragmentManager(); fragmentManager.beginTransaction().replace(R.id.container,fragment).commit(); // Выделяем выбранный пункт меню в шторке item.setChecked(true); // Выводим выбранный пункт в заголовке setTitle(item.getTitle()); DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); drawer.closeDrawer(GravityCompat.START); return true; } public String getMyData() { return mId; }

Fragment Markup Code:

 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.asus.hackaton.view.examview.ResultsFragment"> <TextView android:layout_width="wrap_content" android:text="myFragment with Results" android:layout_height="wrap_content" />

RecyclerView markup code:

 <android.support.v7.widget.RecyclerView android:layout_width="match_parent" android:id="@+id/recycler_view_all" android:scrollbars="vertical" android:layout_height="match_parent" />

Closed due to the fact that off-topic participants Pavel Mayorov , user194374, fori1ton , Mikhail Vaysman , Harry 19 Jan '17 at 5:23 .

It seems that this question does not correspond to the subject of the site. Those who voted to close it indicated the following reason:

  • “Questions asking for help with debugging (“ why does this code not work? ”) Should include the desired behavior, a specific problem or error, and a minimum code for playing it right in the question . Questions without an explicit description of the problem are useless for other visitors. See How to create minimal, self-sufficient and reproducible example . " - Pavel Mayorov, Community Spirit, fori1ton, Mikhail Vaysman, Harry
If the question can be reformulated according to the rules set out in the certificate , edit it .

  • one
    And on what line swears what null? - Iman
  • one
    You have something with formatting code. It is not even clear if you actually have a RecyclerView in the markup of the fragment - YuriySPb ♦

1 answer 1

Judging by indirect signs, in the first code fragment with markup, it is the third fragment in the whole question, this is R.layout.fragment_results. It does not contain a RecyclerView element with id recycler_view_all . Therefore, findViewById() returns a valid null.

 View view = inflater.inflate(R.layout.fragment_results, container, false); recyclerView = (RecyclerView) view.findViewById(R.id.recycler_view_all);

Your RecyclerView in a different markup, but how it is called and where it is used in the code is impossible to understand from the question.