All geek questions in one place

Android fragments must be static

I have this error, but I do not know how to resolve this error.

Error: fragments must be static so that they can be re-created by the system, and anonymous classes are not static [ValidFragment]

Please help me if you know how to solve

This is MainActivity.java

import android.annotation.TargetApi; import android.app.ProgressDialog; import android.content.BroadcastReceiver; import android.content.Context; import android.content.DialogInterface; import android.content.Intent; import android.content.IntentFilter; import android.content.SharedPreferences; import android.content.res.ColorStateList; import android.content.res.Configuration; import android.graphics.Color; import android.os.Build; import android.os.Bundle; import android.preference.PreferenceManager; import android.support.design.widget.FloatingActionButton; import android.support.design.widget.NavigationView; import android.support.design.widget.Snackbar; import android.support.design.widget.TabLayout; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentPagerAdapter; import android.support.v4.content.LocalBroadcastManager; import android.support.v4.view.GravityCompat; import android.support.v4.view.ViewPager; import android.support.v4.widget.DrawerLayout; import android.support.v7.app.ActionBar; import android.support.v7.app.AlertDialog; import android.support.v7.app.AppCompatActivity; import android.support.v7.widget.Toolbar; import android.util.Log; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.TextView; import android.widget.Toast; import com.google.android.gms.common.ConnectionResult; import com.google.android.gms.common.GoogleApiAvailability; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.util.ArrayList; import java.util.List; public class MainActivity extends AppCompatActivity { private DrawerLayout mDrawerLayout; private String keyPref = "test"; private SharedPreferences pref; private static SharedPreferences.Editor editor; private static ViewPager view; private FoodListFragment makanan = new FoodListFragment() { @Override public void doRefresh() { updateData(); } }; private FoodListFragment minuman = new FoodListFragment() { @Override public void doRefresh() { updateData(); } }; private FoodListFragment snack = new FoodListFragment() { @Override public void doRefresh() { updateData(); } }; private Adapter adapter = new Adapter(getSupportFragmentManager()); private static final int PLAY_SERVICES_RESOLUTION_REQUEST = 4343; private BroadcastReceiver mRegistrationBroadcastReceiver; private static ProgressDialog loading; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); pref = getApplicationContext().getSharedPreferences(keyPref, MODE_PRIVATE); editor = pref.edit(); Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); final ActionBar ab = getSupportActionBar(); ab.setHomeAsUpIndicator(R.drawable.ic_menu); ab.setDisplayHomeAsUpEnabled(true); mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout); NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view); if (navigationView != null) { setupDrawerContent(navigationView); } ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager); if (viewPager != null) { setupViewPager(viewPager); } FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab); fab.setBackgroundTintList(ColorStateList.valueOf(Color.rgb(183,28,28))); fab.setOnClickListener(new View.OnClickListener() { @TargetApi(Build.VERSION_CODES.LOLLIPOP) @Override public void onClick(View view) { Intent intent = new Intent(getApplicationContext(), CartActivity.class); MainActivity.this.startActivity(intent); } }); TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs); tabLayout.setupWithViewPager(viewPager); DBHelper db = new DBHelper(this); mRegistrationBroadcastReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { //mRegistrationProgressBar.setVisibility(ProgressBar.GONE); SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context); boolean sentToken = sharedPreferences .getBoolean(QuickstartPreferences.SENT_TOKEN_TO_SERVER, false); } }; loading = new ProgressDialog(this); loading.setMessage("Loading"); loading.setTitle("Menu"); updateData(); } @Override public boolean onCreateOptionsMenu(Menu menu) { return true; } @Override protected void onPause() { super.onPause(); LocalBroadcastManager.getInstance(this).unregisterReceiver(mRegistrationBroadcastReceiver); } @Override protected void onResume() { super.onResume(); LocalBroadcastManager.getInstance(this).registerReceiver(mRegistrationBroadcastReceiver, new IntentFilter(QuickstartPreferences.REGISTRATION_COMPLETE)); } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case android.R.id.home: mDrawerLayout.openDrawer(GravityCompat.START); return true; } return super.onOptionsItemSelected(item); } public void updateData() { ServerHelper server = new ServerHelper() { @Override public void onStart() { loading.show(); } @Override public void onFinish() { loading.dismiss(); } @Override public void onSuccess(int statusCode, String response) { try { editor.putString("response", response); editor.commit(); makanan.clearFood(); minuman.clearFood(); snack.clearFood(); JSONArray foods = new JSONArray(response); for (int i = 0; i <= foods.length()-1; i++) { JSONObject object = foods.getJSONObject(i); JSONObject subs = object.getJSONObject("SubCategory"); FoodCategory addFood = new FoodCategory(subs.getString("name"), subs.getString("photo")); if (subs.getString("categories_id").contains("1")) { makanan.addFood(addFood); } else if (subs.getString("categories_id").contains("2")) { minuman.addFood(addFood); } else if (subs.getString("categories_id").contains("3")) { snack.addFood(addFood); } } makanan.doneRefresh(); minuman.doneRefresh(); snack.doneRefresh(); } catch (JSONException e) { e.printStackTrace(); Toast.makeText(view.getContext(),"Terjadi masalah koneksi, silahkan coba kembali", Toast.LENGTH_LONG).show(); } loading.dismiss(); } @Override public void onFailure(int statusCode, String response) { if (view != null) { Snackbar.make(view, "Terjadi Masalah Koneksi", Snackbar.LENGTH_LONG) .setAction("Action", null).show(); } else { Toast.makeText(MainActivity.this,"Terjadi Masalah Koneksi", Toast.LENGTH_LONG).show(); } makanan.doneRefresh(); minuman.doneRefresh(); snack.doneRefresh(); loading.dismiss(); } }; server.getAllSubs(); } private void setupViewPager(ViewPager viewPager) { makanan.setRetainInstance(true); minuman.setRetainInstance(true); snack.setRetainInstance(true); adapter.addFragment(makanan, "Makanan"); adapter.addFragment(minuman, "Minuman"); adapter.addFragment(snack, "Snack"); viewPager.setAdapter(adapter); updateData(); } @Override public void onConfigurationChanged(Configuration newConfig) { super.onConfigurationChanged(newConfig); } private void setupDrawerContent(final NavigationView navigationView) { View header = navigationView.getHeaderView(0); TextView username = (TextView) header.findViewById(R.id.main_username); DBHelper db = new DBHelper(this); username.setText(db.getUsers().getName()); navigationView.setNavigationItemSelectedListener( new NavigationView.OnNavigationItemSelectedListener() { @Override public boolean onNavigationItemSelected(MenuItem menuItem) { switch (menuItem.getItemId()) { case R.id.nav_home: { menuItem.setChecked(true); break; } case R.id.nav_order: { navigationView.getMenu().getItem(0).setChecked(true); Intent order = new Intent(MainActivity.this, OrderActivity.class); startActivity(order); break; } case R.id.nav_cart: { navigationView.getMenu().getItem(0).setChecked(true); Intent cart = new Intent(MainActivity.this, CartActivity.class); startActivity(cart); break; } case R.id.nav_logout: { AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this); dialog.setMessage("Anda yakin ingin logout akun anda ?"); dialog.setNegativeButton("Batal", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface arg0, int arg1) { } }); dialog.setPositiveButton("Keluar", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface arg0, int arg1) { DBHelper logout = new DBHelper(MainActivity.this); logout.clearSPConfig(); LocalBroadcastManager.getInstance(MainActivity.this).unregisterReceiver(mRegistrationBroadcastReceiver); Intent goLogin = new Intent(MainActivity.this, LoginMainActivity.class); startActivity(goLogin); } }); AlertDialog alertDialog = dialog.create(); alertDialog.show(); } } mDrawerLayout.closeDrawers(); return true; } }); } public static class Adapter extends FragmentPagerAdapter { private final List<Fragment> mFragments = new ArrayList<>(); private final List<String> mFragmentTitles = new ArrayList<>(); public Adapter(FragmentManager fm) { super(fm); } public void addFragment(Fragment fragment, String title) { mFragments.add(fragment); mFragmentTitles.add(title); } @Override public Fragment getItem(int position) { return mFragments.get(position); } @Override public int getCount() { return mFragments.size(); } @Override public CharSequence getPageTitle(int position) { return mFragmentTitles.get(position); } } }

and this is the fragment class FoodListFragment.java

 import android.graphics.Color; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.annotation.UiThread; import android.support.design.widget.Snackbar; import android.support.v4.app.Fragment; import android.support.v4.widget.SwipeRefreshLayout; import android.support.v7.widget.GridLayoutManager; import android.support.v7.widget.RecyclerView; import android.util.Log; import android.view.InflateException; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.util.ArrayList; public abstract class FoodListFragment extends Fragment { private ArrayList<FoodCategory> foodList = new ArrayList<FoodCategory>(); private RecyclerView rv; private RecyclerViewAdapter adapter; private SwipeRefreshLayout swipeLayout; private View view; FoodListFragment() { } public void addFoods(ArrayList<FoodCategory> food) { foodList = food; if (adapter != null) { adapter.notifyDataSetChanged(); } } public void addFood(FoodCategory food) { foodList.add(food); if (adapter != null) { adapter.notifyDataSetChanged(); } } public void clearFood() { foodList.clear(); } @Nullable @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // final RecyclerView rv = (RecyclerView) inflater.inflate(R.layout.fragment_food_list, container, false); view = inflater.inflate(R.layout.fragment_food_list, null); swipeLayout = (SwipeRefreshLayout) view.findViewById(R.id.swipe_container); swipeLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() { @Override public void onRefresh() { doRefresh(); } }); swipeLayout.setColorSchemeColors(Color.RED, Color.GRAY); RecyclerView rv = (RecyclerView) view.findViewById(R.id.recyclerview); setupRecyclerView(rv); return view; } private void setupRecyclerView(final RecyclerView recyclerView) { //recyclerView.setLayoutManager(new LinearLayoutManager(recyclerView.getContext())); recyclerView.setLayoutManager(new GridLayoutManager(recyclerView.getContext(), 2)); recyclerView.setHasFixedSize(true); setRetainInstance(true); adapter = new RecyclerViewAdapter(getActivity(),foodList); recyclerView.setAdapter(adapter); } public void doneRefresh(){ if (swipeLayout != null) { swipeLayout.setRefreshing(false); } } public abstract void doRefresh(); }
+5
source share
1 answer

You declare your Fragment as an abstract class. abstract class could not be created. It can only be used as a base class. The way you try to use it ( anonymous class) is not possible within Android. The Fragment class must be a subclass of Fragment (or an existing subclass) and specific.

Delete keyword abstract

 public class FoodListFragment extends Fragment {

Things you are trying to achieve with

  public abstract void doRefresh();

should be done using the interface.

+5
source

Source: https://habr.com/ru/post/1242773/

More articles:


All Articles