Java Basic 2

1. ArrayList
public static void main(String[] args) {
// TODO Auto-generated method stub
ArrayList<String> list1 = new ArrayList<String>();
list1.add("Zoloo");
list1.add("Bataa");
list1.add("Miigaa");
list1.add("Hurlee");
String input = JOptionPane.showInputDialog("Please enter name:");
list1.add(input);
String msg="";
for(String s: list1) msg+=s + "\n";
JOptionPane.showMessageDialog(null, msg);
}
2. Reading and writing files 
public static void main(String[] args) {
// TODO Auto-generated method stub
try {
String[] array = new String[]{"Carmelo Anthony",
                                                                        "Lebron James", "Kevin Durant",
                                                                        "Paul Pierce", "Paul George" };
BufferedWriter bw = new BufferedWriter(new FileWriter("file.txt"));
for(String s : array)
bw.write(s + "\n");
bw.close();
BufferedReader br = new BufferedReader(new FileReader("file.txt"));
String s = "";
String msg= "";
while((s = br.readLine())!=null)
msg += s + "\n";
br.close();
JOptionPane.showMessageDialog(null, msg);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
3. Map and HashMap
public static void main(String[] args) {
// TODO Auto-generated method stub
HashMap<String, Integer> map = new HashMap<String, Integer>();
map.put("Carmelo", 15);
map.put("Lebron", 23);
map.put("Kobe", 24);
map.put("Duncan", 21);
map.put("Dirk", 41);
int markofKobe = map.get("Kobe");
System.out.println("Marks of Kobe :" + markofKobe);
int markofDuncan = map.get("Duncan");
System.out.println("Marks of Duncan :" + markofDuncan);
map.remove("Kobe");
if(map.containsKey("Kobe"))
System.out.println("Kobe exists!");
else System.out.println("Kobe is gone!");
for(Entry<String, Integer> s : map.entrySet())
System.out.println("Key: " + s.getKey() + " Value: " + s.getValue());
}

4. Interface Example
Interface:
public interface Person {
public String whoRyou();
public String getName();
}

Class 2:
public class GoodPerson implements Person{

String name="";
public GoodPerson(String n) {
// TODO Auto-generated constructor stub
name = n;
}
@Override
public String whoRyou() {
// TODO Auto-generated method stub
return "Good";
}
@Override
public String getName() {
// TODO Auto-generated method stub
return name;
}
}

Class 1:
public class BadPerson implements Person{
String name="";

public BadPerson(String n) {
// TODO Auto-generated constructor stub
name  = n;
}
@Override
public String whoRyou() {
// TODO Auto-generated method stub
return "Bad";
}

@Override
public String getName() {
// TODO Auto-generated method stub
return name;
}
}
Main Class:
public class Killer {
public static void main(String[] args){
GoodPerson gp1 = new GoodPerson("Percy");
GoodPerson gp2 = new GoodPerson("Harry");
BadPerson bp1 = new BadPerson("Black");
BadPerson bp2 = new BadPerson("Reddy");
kill(gp1);
kill(gp2);
kill(bp1);
kill(bp2);
}
public static void kill(Person p){
if(p instanceof BadPerson)
System.out.println("Killed " + p.getName() + ". Feels good to kill a bad person.");
else if(p instanceof GoodPerson)
System.out.println("Killed " + p.getName() + ". Cannot kill a good person.");
}
}
5. Abstraction 
public abstract class Shape {

String colorname = "";
int vertices = 0;
public abstract void Draw();
public String getColorname() {
return colorname;
}
public void setColorname(String colorname) {
this.colorname = colorname;
}
public int getVertices() {
return vertices;
}
public void setVertices(int vertices) {
this.vertices = vertices;
}
}
public class Circle extends Shape{

public Circle(String n){
super.setColorname(n);
super.setVertices(0);
System.out.println("Circle has been created!");
}
@Override
public void Draw() {
// TODO Auto-generated method stub
System.out.println("Circle has been drawn");
}
}
main Class:
public static void main(String[] args){
Circle c1=  new Circle("Black");
Circle c2 = new Circle("Red");
Shape c3 = new Circle("Blue");
c1.Draw();
c2.Draw();
c3.Draw();
}
https://www.youtube.com/playlist?list=PL8F0C07390BAC102A

Java GUI Basic 1

1. JAVA GUI
JRadioButton Example:

public class someClass extends JFrame{

      JTextField tf;

      Font pf;

      Font bf;

      Font itf;

      Font bif;

      JRadioButton pb;

      JRadioButton bb;

      JRadioButton ib;

      JRadioButton bib;

      ButtonGroup group;

     

      public someClass(){

            super("The Title");

            setLayout(new FlowLayout());

            tf = new JTextField("Bucky is awesome and hot", 25);

            add(tf);

            pb = new JRadioButton("plain",true);

            bb = new JRadioButton("bold", false);

            ib = new JRadioButton("italic", false);

            bib = new JRadioButton("bold and italic", false);

            add(pb);

            add(bb);

            add(ib);

            add(bib);

           

            group = new ButtonGroup();

            group.add(pb);

            group.add(bb);

            group.add(ib);

            group.add(bib);

           

            pf = new Font("Serif", Font.PLAIN, 14);

            bf = new Font("Serif", Font.BOLD, 14);

            itf = new Font("Serif", Font.ITALIC, 14);

            bif = new Font("Serif", Font.BOLD + Font.ITALIC, 14);

           

            tf.setFont(pf);

            pb.addItemListener(new HandlerClass(pf));

            bb.addItemListener(new HandlerClass(bf));

            ib.addItemListener(new HandlerClass(itf));

            bib.addItemListener(new HandlerClass(bif));

      }

     

      class HandlerClass implements ItemListener{

            Font font;

           

            public HandlerClass(Font f){

                  font = f;

            }

            @Override

            public void itemStateChanged(ItemEvent arg0) {

                  // TODO Auto-generated method stub

                  tf.setFont(font);

            }

           

      }

     

}

mainClass:

      public static void main(String[] args) {

            // TODO Auto-generated method stub

            someClass sc = new someClass();

            sc.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            sc.setSize(300, 200);

            sc.setVisible(true);

      }

Result:

JList Example:

public class someClass extends JFrame{

      JList list;

      static String[] colornames = {"black", "blue", "red", "white"};

      static Color[] colors = {Color.BLACK, Color.BLUE, Color.RED, Color.WHITE};

      public someClass(){

            super("Title");

            setLayout(new FlowLayout());

            list = new JList(colornames);

            list.setVisibleRowCount(4);

            list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);

            add(new JScrollPane(list));

           

            list.addListSelectionListener(new ListSelectionListener() {

                 

                  @Override

                  public void valueChanged(ListSelectionEvent arg0) {

                        // TODO Auto-generated method stub

                        getContentPane().setBackground(colors[list.getSelectedIndex()]);

                  }

            });

      }

}

Result:

Multiple Selection List Example:

public class someClass extends JFrame{

      JList leftlist;

      JList rightlist;

      JButton movebutton;

     

      static String[] food = {"bacon", "wings", "ham", "beef", "orange","banana"};

     

      public someClass(){

            super("Title");

            setLayout(new FlowLayout());

           

            leftlist = new JList(food);

            leftlist.setVisibleRowCount(4);

leftlist.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);

            add(new JScrollPane(leftlist));

            movebutton = new JButton("Move--->");

            movebutton.addActionListener(new ActionListener() {

                 

                  @Override

                  public void actionPerformed(ActionEvent arg0) {

                        // TODO Auto-generated method stub

                        rightlist.setListData(leftlist.getSelectedValues());

                  }

            });

           

            add(movebutton);

            rightlist = new JList();

            rightlist.setVisibleRowCount(3);

            rightlist.setFixedCellWidth(100);

            rightlist.setFixedCellHeight(15);

rightlist.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);

            add(new JScrollPane(rightlist));

           

      }

}

Result:

Simple Adapter Class Example

MouseAdapter Class:

public class Gui extends JFrame {

      private String details;

      private JLabel statusbar;

     

      public Gui(){

            super("Title");

           

            statusbar = new JLabel("This is default");

            add(statusbar, BorderLayout.SOUTH);

            addMouseListener(new MouseClass());

      }

     

      private class MouseClass extends MouseAdapter{

            public void mouseClicked(MouseEvent ev){

            details = String.format("You clicked %d", ev.getClickCount());

                  if(ev.isMetaDown())

                        details +=" with right mouse button";

                  else if(ev.isAltDown())

                        details +=" either center mouse button";

                  else details +=" with left mouse button";

                 

                  statusbar.setText(details);  

            }

      }

}

Main class:

      public static void main(String[] args) {

            // TODO Auto-generated method stub

            Gui go = new Gui();

            go.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            go.setSize(300, 200);

            go.setVisible(true);

      }

Result:

FlowLayout:

public class someClass extends JFrame{

      JButton a;

      JButton b;

      JButton c;

      FlowLayout layout;

      Container cont;

     

      public someClass(){

            super("Layout tutorial");

            layout = new FlowLayout();

            cont = getContentPane();

            setLayout(layout);

            a = new JButton("Left");

            add(a);

            a.addActionListener(new ActionListener() {

                 

                  @Override

                  public void actionPerformed(ActionEvent arg0) {

                        // TODO Auto-generated method stub

                        layout.setAlignment(FlowLayout.LEFT);

                        layout.layoutContainer(cont);

                  }

            });

            // center

            b = new JButton("Center");

            add(b);

            b.addActionListener(new ActionListener() {

                 

                  @Override

                  public void actionPerformed(ActionEvent arg0) {

                        // TODO Auto-generated method stub

                        layout.setAlignment(FlowLayout.CENTER);

                        layout.layoutContainer(cont);

                  }

            });

            // right

            c = new JButton("Right");

            add(c);

            c.addActionListener(new ActionListener() {

                 

                  @Override

                  public void actionPerformed(ActionEvent arg0) {

                        // TODO Auto-generated method stub

                        layout.setAlignment(FlowLayout.RIGHT);

                        layout.layoutContainer(cont);

                  }

            });

      }

     

}

Main class:

      public static void main(String[] args) {

            // TODO Auto-generated method stub

            someClass sc = new someClass();

            sc.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            sc.setSize(300, 100);

            sc.setVisible(true);

      }

Drawing Graphics:

public class someClass extends JPanel{

      public void paintComponent(Graphics g){

            super.paintComponent(g);

            this.setBackground(Color.WHITE);

            g.setColor(Color.WHITE);

            g.drawLine(10, 25, 200, 45);

            g.setColor(Color.RED);

            g.drawRect(10, 55, 100, 30);

            g.setColor(Color.GREEN);

            g.fillOval(10, 95, 100, 30);

            g.setColor(Color.ORANGE);

            g.fill3DRect(10, 160, 100, 50, true);

            g.setColor(Color.BLACK);

            g.drawString("This is string", 15, 150);

           

      }

}

Main class:

      public static void main(String[] args) {

            // TODO Auto-generated method stub

            JFrame jf = new JFrame("Title");

            jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            someClass sc = new someClass();

            sc.setBackground(Color.WHITE);

            jf.add(sc);

            jf.setSize(500, 300);

            jf.setVisible(true);

      }

Result: