How to display sqlite database content on Listview in fragment?

Question

I am currently working on the admin part of my application. I have a database and, I want to display the data in ListView on a fragment. There are no errors in the code however, when I open that particular fragment(UserFragment) it will just logout / go back to the last activity. Can anybody tell me how to achieve this? Below is what I have tried so far,

UserFragment.java

This is my UserFragment (when I open this one in the application it will just go back to the last activity)

 import android.database.Cursor; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v4.app.Fragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import android.widget.ListView; import android.widget.Toast; import java.util.ArrayList; public class UserFragment extends Fragment { dataconnect myDB; ArrayList < String > items_user; ArrayAdapter adapter; ListView userList; @Nullable @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { final View view = inflater.inflate(R.layout.fragment_user, container, false); items_user = new ArrayList < > (); userList = (ListView) view.findViewById(R.id.listView_users); viewData(); return view; } private void viewData() { Cursor cursor = myDB.viewData(); if (cursor.getCount() == 0) { Toast.makeText(getActivity(), "No data to show", Toast.LENGTH_SHORT).show(); } else { while (cursor.moveToNext()) { items_user.add(cursor.getString(1)); } adapter = new ArrayAdapter < > (getActivity(), android.R.layout.simple_list_item_1, items_user); userList.setAdapter(adapter); } } } 

This is my dataconnect.java (DatabaseHelper)

 import android.content.ContentValues; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; public class dataconnect extends SQLiteOpenHelper { public static final int DATABASE_VERSION = 1; public static final String DATABASE_NAME = "db_jeepy.db"; public static final String TABLE_NAME = "tbl_register"; public static final String COLUMN_ID = "UID"; public static final String COLUMN_FNAME = "FNAME"; public static final String COLUMN_EMAIL = "EMAIL"; public static final String COLUMN_UNAME = "UNAME"; public static final String COLUMN_PWORD = "PWORD"; SQLiteDatabase sqLiteDatabase; public static final String TABLE_CREATE = "create table tbl_register (UID integer primary key not null auto_increment, FNAME text not null, EMAIL text not null, UNAME text not null, PWORD text not null )"; public dataconnect(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase sqLiteDatabase) { sqLiteDatabase.execSQL(TABLE_CREATE); this.sqLiteDatabase = sqLiteDatabase; } public String searchPass(String uname) { sqLiteDatabase = this.getReadableDatabase(); String query = "select UNAME, PWORD from " + TABLE_NAME; Cursor cursor = sqLiteDatabase.rawQuery(query, null); String a, b; b = "not found"; if (cursor.moveToFirst()) { do { a = cursor.getString(0); b = cursor.getString(1); if (a.equals(uname)) { b = cursor.getString(1); break; } } while (cursor.moveToNext()); } return b; } @Override public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) { String query = "DROP TABLE IF EXISTS " + TABLE_NAME; sqLiteDatabase.execSQL(query); this.onCreate(sqLiteDatabase); } public void insertContact(Contact c) { sqLiteDatabase = this.getWritableDatabase(); ContentValues values = new ContentValues(); String query = "select * from " + TABLE_NAME; Cursor cursor = sqLiteDatabase.rawQuery(query, null); int count = cursor.getCount(); values.put(COLUMN_ID, count); values.put(COLUMN_FNAME, c.getFname()); values.put(COLUMN_EMAIL, c.getEmail()); values.put(COLUMN_UNAME, c.getUname()); values.put(COLUMN_PWORD, c.getPword()); sqLiteDatabase.insert(TABLE_NAME, null, values); sqLiteDatabase.close(); } public boolean insertData(String fname, String email, String uname, String pword) { SQLiteDatabase sqLiteDatabase = this.getWritableDatabase(); ContentValues values = new ContentValues(); values.put(COLUMN_FNAME, fname); values.put(COLUMN_EMAIL, email); values.put(COLUMN_UNAME, uname); values.put(COLUMN_PWORD, pword); long result = sqLiteDatabase.insert(TABLE_NAME, null, values); if (result == -1) return false; else return true; } public Cursor viewData (){ SQLiteDatabase sqLiteDatabase = this.getReadableDatabase(); String query = "Select * from "+TABLE_NAME; Cursor cursor = sqLiteDatabase.rawQuery(query,null); return cursor; } } 

adminopen.java

This is the activity where I put/open UserFragment

 import android.content.DialogInterface; import android.content.Intent; import android.support.annotation.NonNull; import android.support.design.widget.NavigationView; import android.support.v4.view.GravityCompat; import android.support.v4.widget.DrawerLayout; import android.support.v7.app.ActionBarDrawerToggle; import android.support.v7.app.AlertDialog; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.MenuItem; public class adminopen extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener { private DrawerLayout drawer; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_adminopen); drawer = (DrawerLayout) findViewById(R.id.drawer_layout); NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view); navigationView.setNavigationItemSelectedListener(this); ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, R.string.navigation_drawer_open, R.string.navigation_drawer_close); drawer.addDrawerListener(toggle); toggle.syncState(); if (savedInstanceState == null) { getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new JeepsFragment()).commit(); navigationView.setCheckedItem(R.id.nav_jeeps); } } @Override public void onBackPressed() { if (drawer.isDrawerOpen(GravityCompat.START)) { drawer.closeDrawer(GravityCompat.START); } else { AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setCancelable(false); builder.setMessage("Do you want to logout?"); builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { Intent a = new Intent(adminopen.this, MainActivity.class); startActivity(a); } }); builder.setNegativeButton("No", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { dialogInterface.cancel(); } }); AlertDialog dialog = builder.create(); dialog.show(); } } @Override public boolean onNavigationItemSelected(@NonNull MenuItem item) { switch (item.getItemId()) { case R.id.nav_users: getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new UserFragment()).commit(); break; case R.id.nav_jeeps: getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new JeepsFragment()).commit(); break; } drawer.closeDrawer(GravityCompat.START); return true; } } 

Answer 1

I already fix it ^.^

I just add

mContext =getActivity(); myDB = new dataconnect(mContext);

in the OnCreateView of my fragment.

so the code become like this..

 import android.content.Context; import android.database.Cursor; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v4.app.Fragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.ListView; import android.widget.Toast; import java.util.ArrayList; public class UserFragment extends Fragment { dataconnect myDB; ArrayList < String > items_user; ArrayAdapter adapter; ListView userList; private Context mContext; @Nullable @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { final View view = inflater.inflate(R.layout.fragment_user, container, false); mContext = getActivity(); myDB = new dataconnect(mContext); items_user = new ArrayList < > (); userList = (ListView) view.findViewById(R.id.listView_users); viewData(); userList.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView << ? > adapterView, View view, int i, long l) { String text = userList.getItemAtPosition(i).toString(); Toast.makeText(getContext(), "" + text, Toast.LENGTH_SHORT).show(); } }); return view; } private void viewData() { Cursor cursor = myDB.viewData(); if (cursor.getCount() == 0) { Toast.makeText(getActivity(), "No data to show", Toast.LENGTH_SHORT).show(); } else { while (cursor.moveToNext()) { items_user.add(cursor.getString(1)); } adapter = new ArrayAdapter < > (getActivity(), android.R.layout.simple_list_item_1, items_user); userList.setAdapter(adapter); } } }