Wednesday, July 15, 2015

How to check system installation date in Windows computer?

If you want to check windows installation date, go to command prompt and type the following command.

systeminfo | find/i "install date"

And you will get something like this.




Tuesday, July 14, 2015

How use getContentResolver in a class without activity?

In android development, methods like getContentResolver() need context to call these kinds of methods. But some classes does not have  Context. In those cases it is used like this.
  • Application: getApplicationContext() 
  • Activity: this (as Activity extends Context) 
  • Fragment: getActivity()

Saturday, June 20, 2015

HTTP Status 405 - HTTP method GET is not supported by this URL

When I'm working with Java Servlet, I encountered "HTTP Status 405" error. But code seems to legit. The problem was, servlet doGet method calling super method.

package uk.co.andromedatech.onlineradio;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Test extends HttpServlet{

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
// TODO Auto-generated method stub
super.doGet(req, resp);
resp.setContentType("text/html");

PrintWriter out = resp.getWriter();
out.println("Leann....");
}

}

After removal of red marked code selection, servlet compiled and started to work.

Sunday, October 26, 2014

C# - List all the links in a website.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.Text.RegularExpressions;

namespace ProgrammingDotNet
{
    class Program
    {
        public static void Main(string[] args)
        {
            StreamReader reader = null;
            try
            {
                WebRequest request = WebRequest.Create("http://www.techexams.net/");
                WebResponse response = request.GetResponse();
                reader = new StreamReader(response.GetResponseStream());
                string content = reader.ReadToEnd();

                Regex regex = new Regex("href\\s*=\\s*\"([^\"]*)\"", RegexOptions.IgnoreCase);

                MatchCollection matches = regex.Matches(content);
                foreach (Match match in matches)
                {
                    Console.WriteLine(match.Groups[1]);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
            finally
            {
                if (reader != null)
                {
                    reader.Close();
                }
            }
            Console.ReadLine();
        }
    }
}

C# - Simple program that dumps text files to the windows console.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


namespace ProgrammingDotNet
{
    class Program
    {
        public static void Main(string[] args)
        {
            String filename = "C:\\Users\\Isuru\\Desktop\\google_5000000.txt";
            StreamReader reader = new StreamReader(filename);
            for (String line = reader.ReadLine(); line != null; line = reader.ReadLine())
            {
                Console.WriteLine(line);
            }
            reader.Close();
            Console.ReadLine();
        }
    }
}

Tuesday, April 29, 2014

Unable to get system library for project

You may not able to build your android project because android adt cannot find the system library for project.

And following compile errors may occur due to that problem.

The type java.lang.Object cannot be resolved.

To solve the problem open build path for the project, and in Android tab select different project build target.


Thursday, April 24, 2014

SQLite For Android Source Codes

public class SQLiteHelper extends SQLiteOpenHelper {
 private static final String DATABASE_NAME = "my_database.db";
 // TOGGLE THIS NUMBER FOR UPDATING TABLES AND DATABASE

 private static final int DATABASE_VERSION = 1;
 // NAME OF TABLE YOU WISH TO CREATE
 public static final String TABLE_NAME = "my_table";
 // SOME SAMPLE FIELDS
 public static final String UID = "_id";
 public static final String NAME = "name";
 
 SQLiteHelper(Context context) {
  super(context, DATABASE_NAME, null, DATABASE_VERSION);
 }
 @Override
 public void onCreate(SQLiteDatabase db) {
  db.execSQL("CREATE TABLE " + TABLE_NAME + " (" + UID + "
  INTEGER PRIMARY KEY AUTOINCREMENT," + NAME
  + " VARCHAR(255));");
 }
 @Override
 public void onUpgrade(SQLiteDatabase db, int oldVersion,
   int newVersion) {
  Log.w("LOG_TAG", "Upgrading database from version " +
   oldVersion + " to " + newVersion + ", which will destroy all old data");
  // KILL PREVIOUS TABLE IF UPGRADED
  db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
  // CREATE NEW INSTANCE OF TABLE
  onCreate(db);
 }
}


Implementing the database helper class.

public class SQLiteExample extends Activity {
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  // INIT OUR SQLITE HELPER
  SQLiteHelper sqh = new SQLiteHelper(this);
  // RETRIEVE A READABLE AND WRITEABLE DATABASE
  SQLiteDatabase sqdb = sqh.getWritableDatabase();
  
  
  // METHOD #1: INSERT USING CONTENTVALUE CLASS
  ContentValues cv = new ContentValues();
  cv.put(SQLiteHelper.NAME, "jason wei");
  // CALL INSERT METHOD
  sqdb.insert(SQLiteHelper.TABLE_NAME, SQLiteHelper.NAME, cv);
  
  
  // METHOD #2: INSERT USING SQL QUERY
  String insertQuery = "INSERT INTO " +
  SQLiteHelper.TABLE_NAME + " (" + SQLiteHelper.NAME + ") VALUES ('jwei')";
  sqdb.execSQL(insertQuery);

  // METHOD #1: QUERY USING WRAPPER METHOD
  Cursor c = sqdb.query(SQLiteHelper.TABLE_NAME,
   new String[] { SQLiteHelper.UID, SQLiteHelper.NAME },
    null, null, null, null, null);
  while (c.moveToNext()) {
  // GET COLUMN INDICES + VALUES OF THOSE COLUMNS
  int id = c.getInt(c.getColumnIndex(SQLiteHelper.UID));
  String name = c.getString(c.getColumnIndex(SQLiteHelper.NAME));
  Log.i("LOG_TAG", "ROW " + id + " HAS NAME " + name);
  }
  c.close();

  // METHOD #2: QUERY USING SQL SELECT QUERY
  String query = "SELECT " + SQLiteHelper.UID + ", " +
   SQLiteHelper.NAME + " FROM " + SQLiteHelper.TABLE_NAME;
  Cursor c2 = sqdb.rawQuery(query, null);
  while (c2.moveToNext()) {
  int id = c2.getInt(c2.getColumnIndex(SQLiteHelper.UID));
  String name = c2.getString(c2.getColumnIndex(SQLiteHelper.NAME));
  Log.i("LOG_TAG", "ROW " + id + " HAS NAME " + name);
  }
  c2.close();
  
  // CLOSE DATABASE CONNECTIONS
  sqdb.close();
  sqh.close();
 }
}