базы данных не создается в андроида с использованием SQLite Databse

Question

я сделал простой андроид Databse демонстрационную программу для учебных целей я reffred Ссылка, как показано ниже: enter link description here

Я прошел через шаг за шагом, но база данных не создается в моем программа мой код, как показано ниже:

contactlistAdapter.java

package com.example.dblistview; 

import java.util.ArrayList; 

import android.content.Context; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.BaseAdapter; 
import android.widget.TextView; 

public class ContactListAdapter extends BaseAdapter { 
    Context context; 
    ArrayList<ContactListItems> contactList; 
    public ContactListAdapter(Context context, ArrayList<ContactListItems> list) { 

     this.context = context; 
     contactList = list; 
    } 
    @Override 
    public int getCount() { 
     // TODO Auto-generated method stub 
    return contactList.size(); 
    } 

    @Override 
    public Object getItem(int pos) { 
     // TODO Auto-generated method stub 
     return contactList.get(pos); 
    } 

    @Override 
    public long getItemId(int arg0) { 
     // TODO Auto-generated method stub 
     return arg0; 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     ContactListItems contactListItems = contactList.get(position); 

      if (convertView == null) { 
       LayoutInflater inflater = (LayoutInflater) context 
         .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
       convertView = inflater.inflate(R.layout.raw, null); 

      } 
      TextView tvSlNo = (TextView) convertView.findViewById(R.id.tv_slno); 
      tvSlNo.setText(contactListItems.getSlno()); 
      TextView tvName = (TextView) convertView.findViewById(R.id.tv_name); 
      tvName.setText(contactListItems.getName()); 
      TextView tvPhone = (TextView) convertView.findViewById(R.id.tv_phone); 
      tvPhone.setText(contactListItems.getPhone()); 

      return convertView; 

    } 

} 

contactListItems.java

package com.example.dblistview; 

public class ContactListItems { 
    String slno; 
    String name; 
    String phone; 

    public String getSlno() { 
     return slno; 
    } 

    public void setSlno(String slno) { 
     this.slno = slno; 
    } 

    public String getName() { 
     return name; 
    } 

    public void setName(String name) { 
     this.name = name; 
    } 

    public String getPhone() { 
     return phone; 
    } 

    public void setPhone(String phone) { 
     this.phone = phone; 
    } 

    } 

main.java

package com.example.dblistview; 

import java.util.ArrayList; 

import android.os.Bundle; 
import android.app.Activity; 
import android.database.Cursor; 
import android.view.Menu; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.ListView; 

public class MainActivity extends Activity { 
sqlHandler sqlHandler; 
ListView lv; 
Button submit; 
EditText nm,fn; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     lv=(ListView)findViewById(R.id.lv_custom_list); 
     nm=(EditText)findViewById(R.id.et_name); 
     fn=(EditText)findViewById(R.id.et_phone); 
     submit=(Button)findViewById(R.id.btn_submit); 

     sqlHandler =new sqlHandler(); 
     submit.setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
      String name=nm.getText().toString(); 
      String fon=fn.getText().toString(); 
      String query = "INSERT INTO PHONE_CONTACTS(name,phone) values ('" 
         + name + "','" + fon + "')"; 
      sqlHandler.executeQuery(query); 

      } 
     }); 

    } 
     private void showList() { 

      ArrayList<ContactListItems> contactList = new ArrayList<ContactListItems>(); 
      contactList.clear(); 
      String query = "SELECT * FROM PHONE_CONTACTS "; 
      Cursor c1 = sqlHandler.selectQuery(query); 
      if (c1 != null && c1.getCount() != 0) { 
      if (c1.moveToFirst()) { 
      do { 
      ContactListItems contactListItems = new ContactListItems(); 

      contactListItems.setSlno(c1.getString(c1 
       .getColumnIndex("slno"))); 
      contactListItems.setName(c1.getString(c1 
       .getColumnIndex("name"))); 
      contactListItems.setPhone(c1.getString(c1 
       .getColumnIndex("phone"))); 
      contactList.add(contactListItems); 

      } while (c1.moveToNext()); 
      } 
      } 
      c1.close(); 

      ContactListAdapter contactListAdapter = new ContactListAdapter(
      MainActivity.this, contactList); 
      lv.setAdapter(contactListAdapter); 

     } 
} 

sqlDbhelper.java

package com.example.dblistview; 

import android.content.Context; 
import android.database.DatabaseErrorHandler; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteDatabase.CursorFactory; 
import android.database.sqlite.SQLiteOpenHelper; 

public class SqlDbhelper extends SQLiteOpenHelper { 
    public static final String DATABASE_TABLE = "PHONE_CONTACTS"; 

    public static final String COLUMN1 = "slno"; 
    public static final String COLUMN2 = "name"; 
    public static final String COLUMN3 = "phone"; 

      private static final String SCRIPT_CREATE_DATABASE = "create table " 
         + DATABASE_TABLE + " (" + COLUMN1 
         + " integer primary key autoincrement, " + COLUMN2 
         + " text not null, " + COLUMN3 + " text not null);"; 

    public SqlDbhelper(Context context, String name, CursorFactory factory, 
      int version) { 
     super(context, name, factory, version); 

    } 

    @Override 
    public void onCreate(SQLiteDatabase db) { 

     db.execSQL(SCRIPT_CREATE_DATABASE); 
    } 

    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 

     db.execSQL("drop table if exists" + DATABASE_TABLE); 
     onCreate(db); 
    } 

} 

sqlhandler.java

package com.example.dblistview; 
import com.example.dblistview.SqlDbhelper; 

import android.content.Context; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 


public class sqlHandler {public static final String DATABASE_NAME = "MY_DATABASE"; 
public static final int DATABASE_VERSION = 1; 
Context context; 
SQLiteDatabase sqlDatabase; 
SqlDbhelper dbHelper; 

public void SqlHandler(Context context) { 

dbHelper = new SqlDbhelper(context, DATABASE_NAME, null, 
    DATABASE_VERSION); 
sqlDatabase = dbHelper.getWritableDatabase(); 
} 

public void executeQuery(String query) { 
try { 

    if (sqlDatabase.isOpen()) { 
    sqlDatabase.close(); 
    } 

    sqlDatabase = dbHelper.getWritableDatabase(); 
    sqlDatabase.execSQL(query); 

} catch (Exception e) { 

    System.out.println("DATABASE ERROR " + e); 
} 

} 

public Cursor selectQuery(String query) { 
Cursor c1 = null; 
try { 

    if (sqlDatabase.isOpen()) { 
    sqlDatabase.close(); 

    } 
    sqlDatabase = dbHelper.getWritableDatabase(); 
    c1 = sqlDatabase.rawQuery(query, null); 

} catch (Exception e) { 

    System.out.println("DATABASE ERROR " + e); 


} 
return c1; 

} 

} 

Answer 1

Try this DatabaseUtil class to create : 

public class DatabaseUtil 
{ 
    private static final String DATABASE_NAME = "database_name"; 
    private static final int DATABASE_VERSION = 1; 
    private static final String TABLE_NAME = "table_name"; 
    private static final String ROW_ID = "_id"; 
    private static final String PARAM1 = "param1"; 
    private static final String PARAM2 = "param2"; 
    private static final String CREATE_TABLE = "create table " + TABLE_NAME + " (" + ROW_ID + " integer primary key autoincrement, "`enter code here` 
      + param1+" text not null, " + param2+ " text not null);"; 
private final Context context; 
private DatabaseHelper mDbHelper; 
private SQLiteDatabase mDb; 

    private static class DatabaseHelper extends SQLiteOpenHelper 
    { 
     DatabaseHelper(Context context) 
     {super(context, DATABASE_NAME, null, DATABASE_VERSION);} 

     @Override 
     public void onCreate(SQLiteDatabase db) 
     {db.execSQL(CREATE_TABLE);} 

     @Override 
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
     {} 
    } 

    public DatabaseUtil(Context c) 
    {this.context = c;} 

    public DatabaseUtil open() throws SQLException 
    { 
     mDbHelper = new DatabaseHelper(context); 
     mDb = mDbHelper.getWritableDatabase(); 
     return this; 
    } 

    public void close() 
    {mDbHelper.close();} 

    public long add(String strparam1,String strparam2) 
    { 
     ContentValues cv = new ContentValues(); 
     cv.put(PARAM1 ,strparam1); 
     cv.put(PARAM2 ,strparam2); 

     return mDb.insert(TABLE_NAME, null, cv); 
    } 

    public Cursor fetchAll() 
    {return mDb.query(TABLE_NAME,new String[] {ROW_ID, PARAM1, PARAM2},null,null,null,null,null);} 

    public boolean deleteTitle(String strparam1) 
    {return mDb.delete(TABLE_NAME,PARAM1 + "='" + strparam1+"'", null)>0;} 
} 

Then to create and add the values, 
DatabaseUtil util = new DatabaseUtil(this); 
util.open(); 
util.add(param1, param2); 
util.close(); 

This will be simpler insert for you. 

Answer 2

Я думаю, что DATABASE_NAME должно быть чем-то вроде «database_name.db». Это означает, что вы должны добавить расширение, потому что это имя файла.

Надеюсь, это вам поможет.