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How to connect method from another class to actionListener?

I'm trying to finish my project about searching graphs, where one of the functions is input (vertex and edges) from user.
I already have a method for this in another class, but now I need to put it into GUI.
I've already tried many of tutorials, but nothing worked. Can somebody help me, how to put the method getInputFromCommand to gui?
I've already tried to copy the method into the GUI, but there was problem with the "return g" because of the void result type, I've tried just to call the method, (I know.. stupid) but it didn't work either.
package Process;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;
public class FindIslands {
String message = "";
int V;
LinkedList<Integer>[] adjListArray;
static LinkedList<String> nodeList = new LinkedList<String>();
// constructor
FindIslands(int V) {
this.V = V;
adjListArray = new LinkedList[V];
for (int i = 0; i < V; i++) {
adjListArray[i] = new LinkedList<Integer>();
}
}
void addEdge(int src, int dest) {
adjListArray[src].add(dest);
adjListArray[dest].add(src);
}
void DFSUtil(int v, boolean[] visited) {
visited[v] = true;
message += getValue(v) + " ";
// System.out.print(getValue(v) + " ");
for (int x : adjListArray[v]) {
if (!visited[x]) {
DFSUtil(x, visited);
}
}
}
void connectedComponents() {
boolean[] visited = new boolean[V];
int count = 0;
message = "";
for (int v = 0; v < V; ++v) {
if (!visited[v]) {
DFSUtil(v, visited);
message += "\n";
// System.out.println();
count++;
}
}
System.out.println("" + count);
System.out.println("");
System.out.println("Vypis ostrovu: ");
String W[] = message.split("\n");
Arrays.sort(W, new java.util.Comparator<String>() {
#Override
public int compare(String s1, String s2) {
// TODO: Argument validation (nullity, length)
return s1.length() - s2.length();// comparison
}
});
for (String string : W) {
System.out.println(string);
}
}
public static void main(String[] args) {
FindIslands g = null; //
String csvFile = "nodefile.txt";
BufferedReader br = null;
String line = "";
int emptyLine = 0;
try {
br = new BufferedReader(new FileReader(csvFile));
while ((line = br.readLine()) != null) {
if (line.equals("")) {
emptyLine = 1;
// System.out.println("found blank line");
}
if (emptyLine == 0) {
// System.out.println(line);
nodeList.add(line);
} else if (line.isEmpty()) {
g = new FindIslands(nodeList.size());
} else {
String[] temp = line.split(",");
g.addEdge(getIndex(temp[0]), getIndex(temp[1]));
}
}
} catch (FileNotFoundException e) {
System.out.println("Soubor nenalezen, zadejte data v danem formatu");
g = getInputFromCommand();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
System.out.println("Pocet ostrovu");
if (g != null) {
g.connectedComponents();
}
}
public static int getIndex(String str) {
return nodeList.indexOf(str);
}
public static String getValue(int index) {
return nodeList.get(index);
}
public static FindIslands getInputFromCommand() {
FindIslands g = null;
BufferedReader br = null;
String line = "";
int emptyLine = 0;
Scanner scanner = new Scanner(System.in);
line = scanner.nextLine();
while (!line.equals("")) {
if (line.equals("--gui")) {
Guicko gui = new Guicko();
gui.setVisible(true);
} else
nodeList.add(line);
line = scanner.nextLine();
}
g = new FindIslands(nodeList.size());
line = scanner.nextLine();
while (!line.equals("")) {
String[] temp = line.split(",");
if (temp.length != 2) {
System.out.println("spatny format zadanych dat, prosim zkuste znovu");
} else {
g.addEdge(getIndex(temp[0]), getIndex(temp[1]));
}
line = scanner.nextLine();
}
return g;
}
}
Where important is the last method "getInputFromCommand()"
and... gui
package Process;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.util.Scanner;
public class Guicko extends JFrame {
private JButton štartButton;
private JPanel panel;
private JTextField textField2;
private JTextArea textArea1;
public Guicko() {
add(panel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
setTitle("Zadej hodnoty");
setSize(500, 400);
textField2.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
FindIslands.getInputFromCommand();
}
});
štartButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String str = "asd";
FindIslands g = null;
g.connectedComponents();
textArea1.setText(str);
}
});
}
public static void main (String args[]){
Guicko gui = new Guicko();
gui.setVisible(true);
}
}

I'm sure there are many correct ways this code can be fixed, but in IMHO, your Guicko class needs to have a FindIslands class member, and I think you need to move some stuff from FindIslands.main() into Guicko.main() or some other method.
Then your "Action Listener" inner classes' actionPerformed methods just delegate to the methods in the FindIslands member instance, like this
....
private FindIslands fi;
public Guicko() {
....
textField2.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
fi = FindIslands.getInputFromCommand();
}
});
startButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String comps = fi.connectedComponents();// method needs to return a string
textArea1.setText(comps);
}
});
}

The whole idea of seperating GUI from domain is to make changes easily. GUI has knowledge of the domain but domain has no knowledge about the GUI. We can use an interface to seperate them, in that case, Domain says , i don't care who implements this interface but whoever implements this interface will get response and can work with me.
So , If we create a new GUI, we can let it implements that interface and the same domain will work with that GUI.
There are many mistakes but in order to make it work and to show you an example i did few changes.
public class Guicko extends JFrame implements PropertyChangeListener{
private JButton štartButton;
private JPanel panel;
private JTextField textField2;
private JTextArea textArea1;
private FindIslands land;
private JTextField textField;
private JButton button;
public Guicko() {
JPanel panel = new JPanel();
super.getContentPane().setLayout(new GridLayout());
//For each gui, there should be one land.
this.setLand(new FindIslands(100));
//Subscribe to the domain so that you can get update if something change in domain.
this.getLand().subscribe(this);
//Dummy buttons are fields(need too initiate first)
textField2 = new JTextField("",30);
štartButton = new JButton();
textField = new JTextField("",30);
button = new JButton();
button.setPreferredSize(new Dimension(100, 40));
button.setText("Get input from Domain");
štartButton.setPreferredSize(new Dimension(100, 40));
textField.setEditable(false);
štartButton.setText("Start");
panel.add(textField2);
panel.add(štartButton);
panel.add(textField);
panel.add(button);
add(panel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
setTitle("Zadej hodnoty");
setSize(500, 400);
//When you type something in , then this function will send it to domain(i mean to function : getInputFromCommand();).
this.addListerToField(štartButton,this.getLand(),textField2);
//Now the second case, suppose you press a button and want something to show up in textfield. In that case , this function will do work.
this.addListerToSecondField(button,this.getLand(),textField);
}
//Here i can catch the events from the domain.
#Override
public void propertyChange(PropertyChangeEvent e) {
if(e.getPropertyName().equals("String changed")) {
this.getTextField().setText((String) e.getNewValue());
}
}
private void addListerToSecondField(JButton button, FindIslands land, JTextField field) {
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
land.requireArgumentsForField();
}
});
}
private void addListerToField(JButton štartButton, FindIslands land, JTextField field) {
štartButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
land.getInputFromCommand(field.getText());
}
});
}
public static void main (String args[]){
Guicko gui = new Guicko();
gui.setVisible(true);
}
public FindIslands getLand() {
return land;
}
public void setLand(FindIslands land) {
this.land = land;
}
public JTextField getTextField() {
return textField;
}
public void setTextField(JTextField textField) {
this.textField = textField;
}
public JButton getButton() {
return button;
}
public void setButton(JButton button) {
this.button = button;
}
Here is the second class. Run it and try to get feeling for it how it works.
public class FindIslands {
String message = "";
int V;
LinkedList<Integer>[] adjListArray;
static LinkedList<String> nodeList = new LinkedList<String>();
// constructor
FindIslands(int V) {
this.V = V;
//initialize the list
this.setListeners(new ArrayList<>());
adjListArray = new LinkedList[V];
for (int i = 0; i < V; i++) {
adjListArray[i] = new LinkedList<Integer>();
}
}
void addEdge(int src, int dest) {
adjListArray[src].add(dest);
adjListArray[dest].add(src);
}
void DFSUtil(int v, boolean[] visited) {
visited[v] = true;
message += getValue(v) + " ";
// System.out.print(getValue(v) + " ");
for (int x : adjListArray[v]) {
if (!visited[x]) {
DFSUtil(x, visited);
}
}
}
void connectedComponents() {
boolean[] visited = new boolean[V];
int count = 0;
message = "";
for (int v = 0; v < V; ++v) {
if (!visited[v]) {
DFSUtil(v, visited);
message += "\n";
// System.out.println();
count++;
}
}
System.out.println("" + count);
System.out.println("");
System.out.println("Vypis ostrovu: ");
String W[] = message.split("\n");
Arrays.sort(W, new java.util.Comparator<String>() {
#Override
public int compare(String s1, String s2) {
// TODO: Argument validation (nullity, length)
return s1.length() - s2.length();// comparison
}
});
for (String string : W) {
System.out.println(string);
}
}
//You need only one main class, not two.----------------------------
/**
public static void main(String[] args) {
FindIslands g = null; //
String csvFile = "nodefile.txt";
BufferedReader br = null;
String line = "";
int emptyLine = 0;
try {
br = new BufferedReader(new FileReader(csvFile));
while ((line = br.readLine()) != null) {
if (line.equals("")) {
emptyLine = 1;
// System.out.println("found blank line");
}
if (emptyLine == 0) {
// System.out.println(line);
nodeList.add(line);
} else if (line.isEmpty()) {
g = new FindIslands(nodeList.size());
} else {
String[] temp = line.split(",");
g.addEdge(getIndex(temp[0]), getIndex(temp[1]));
}
}
} catch (FileNotFoundException e) {
System.out.println("Soubor nenalezen, zadejte data v danem formatu");
g = getInputFromCommand();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
System.out.println("Pocet ostrovu");
if (g != null) {
g.connectedComponents();
}
}
**/
public static int getIndex(String str) {
return nodeList.indexOf(str);
}
public static String getValue(int index) {
return nodeList.get(index);
}
//Static cases are to be avoided.This is the property of object not class.
public void getInputFromCommand(String string) {
//Here you will recieve a string from the GUI and will be printed in command prompt.You can do whatever you want to do with it.
System.out.println("Recieve string is " + string);
//No idea what you are trying to do.
/** FindIslands g = null;
BufferedReader br = null;
String line = "";
int emptyLine = 0;
Scanner scanner = new Scanner(System.in);
line = scanner.nextLine();
while (!line.equals("")) {
if (line.equals("--gui")) {
Guicko gui = new Guicko();
gui.setVisible(true);
} else
nodeList.add(line);
line = scanner.nextLine();
}
g = new FindIslands(nodeList.size());
line = scanner.nextLine();
while (!line.equals("")) {
String[] temp = line.split(",");
if (temp.length != 2) {
System.out.println("spatny format zadanych dat, prosim zkuste znovu");
} else {
g.addEdge(getIndex(temp[0]), getIndex(temp[1]));
}
line = scanner.nextLine();
}
return line;**/
}
//This function is triggered with second button and you can send data to gui as shown below.
public void requireArgumentsForField() {
//Suppose i want to send following string.
String name = "I don't know";
this.getListeners().stream().forEach(e -> {
// I will catch this in view.
e.propertyChange(new PropertyChangeEvent(this, "String changed", null, name));
});
}
private ArrayList<PropertyChangeListener> listeners;
//Let the objects subscibe. You need this to publish the changes in domain.
public void subscribe(PropertyChangeListener listener) {
this.getListeners().add(listener);
}
public ArrayList<PropertyChangeListener> getListeners() {
return listeners;
}
public void setListeners(ArrayList<PropertyChangeListener> listeners) {
this.listeners = listeners;
}

Dynamic Simple Text Editor Java

I have modified code from here for my project.
I want to make a editor that have dynamic text area. Each time I press the enter key, a new text area will create. Sorry, I cannot explain more with English.
Please look my code:
import javax.swing.*;
import javax.swing.text.*;
import java.awt.*;
import java.io.*;
import java.awt.event.*;
import java.util.Hashtable;
public class SimpleEditor extends JFrame {
int count = 0;
private Action openAction = new SimpleEditor.OpenAction();
private Action saveAction = new SimpleEditor.SaveAction();
//private JTextComponent textComp;
private JTextComponent[] textComp2;
//private Hashtable actionHash = new Hashtable();
public static void main(String[] args) {
SimpleEditor editor = new SimpleEditor();
editor.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
editor.setVisible(true);
}
// Create an editor.
public SimpleEditor() {
super("Swing Editor");
//textComp = createTextComponent();
coba();
makeActionsPretty();
Container content = getContentPane();
//content.add(textComp, BorderLayout.CENTER);
for (int i = 0; i < count; i++) {
content.add(textComp2[i], BorderLayout.CENTER);
}
content.add(createToolBar(), BorderLayout.NORTH);
setJMenuBar(createMenuBar());
setSize(320, 240);
}
//coba-coba
protected void coba() {
if (count == 0) {
textComp2 = new JTextComponent[1];
count += 1;
} else {
JTextComponent[] texttemp;
texttemp = new JTextComponent[count];
for (int i = 0; i < count; i++) {
texttemp[i] = createTextComponent();
texttemp[i] = textComp2[i];
}
count += 1;
textComp2 = new JTextComponent[count];
for (int i = 0; i < count - 1; i++) {
textComp2[i] = createTextComponent();
textComp2[i] = texttemp[i];
}
}
}
// Create the JTextComponent subclass.
protected JTextComponent createTextComponent() {
JTextArea ta = new JTextArea();
ta.setFont(new Font("Courier New", Font.PLAIN, 12));
ta.setLineWrap(true);
ta.addKeyListener(new java.awt.event.KeyAdapter() {
public void keyPressed(java.awt.event.KeyEvent ev) {
taKeyPressed(ev);
}
});
return ta;
}
private void taKeyPressed(java.awt.event.KeyEvent ev) {
if (ev.getKeyCode() == 13) {
coba();
}
}
// Add icons and friendly names to actions we care about.
protected void makeActionsPretty() {
Action a;
/*a = textComp.getActionMap().get(DefaultEditorKit.cutAction);
a.putValue(Action.SMALL_ICON, new ImageIcon("icons/cut.gif"));
a.putValue(Action.NAME, "Cut");
a = textComp.getActionMap().get(DefaultEditorKit.copyAction);
a.putValue(Action.SMALL_ICON, new ImageIcon("icons/copy.gif"));
a.putValue(Action.NAME, "Copy");
a = textComp.getActionMap().get(DefaultEditorKit.pasteAction);
a.putValue(Action.SMALL_ICON, new ImageIcon("icons/paste.gif"));
a.putValue(Action.NAME, "Paste");
a = textComp.getActionMap().get(DefaultEditorKit.selectAllAction);
a.putValue(Action.NAME, "Select All");*/
for (int i = 0; i < count; i++) {
a = textComp2[i].getActionMap().get(DefaultEditorKit.cutAction);
a.putValue(Action.SMALL_ICON, new ImageIcon("icons/cut.gif"));
a.putValue(Action.NAME, "Cut");
a = textComp2[i].getActionMap().get(DefaultEditorKit.copyAction);
a.putValue(Action.SMALL_ICON, new ImageIcon("icons/copy.gif"));
a.putValue(Action.NAME, "Copy");
a = textComp2[i].getActionMap().get(DefaultEditorKit.pasteAction);
a.putValue(Action.SMALL_ICON, new ImageIcon("icons/paste.gif"));
a.putValue(Action.NAME, "Paste");
a = textComp2[i].getActionMap().get(DefaultEditorKit.selectAllAction);
a.putValue(Action.NAME, "Select All");
}
}
// Create a simple JToolBar with some buttons.
protected JToolBar createToolBar() {
JToolBar bar = new JToolBar();
// Add simple actions for opening & saving.
bar.add(getOpenAction()).setText("");
bar.add(getSaveAction()).setText("");
bar.addSeparator();
// Add cut/copy/paste buttons.
/*bar.add(textComp.getActionMap().get(DefaultEditorKit.cutAction)).setText("");
bar.add(textComp.getActionMap().get(
DefaultEditorKit.copyAction)).setText("");
bar.add(textComp.getActionMap().get(
DefaultEditorKit.pasteAction)).setText("");*/
for (int i = 0; i < count; i++) {
bar.add(textComp2[i].getActionMap().get(DefaultEditorKit.cutAction)).setText("");
bar.add(textComp2[i].getActionMap().get(
DefaultEditorKit.copyAction)).setText("");
bar.add(textComp2[i].getActionMap().get(
DefaultEditorKit.pasteAction)).setText("");
}
return bar;
}
// Create a JMenuBar with file & edit menus.
protected JMenuBar createMenuBar() {
JMenuBar menubar = new JMenuBar();
JMenu file = new JMenu("File");
JMenu edit = new JMenu("Edit");
menubar.add(file);
menubar.add(edit);
file.add(getOpenAction());
file.add(getSaveAction());
file.add(new SimpleEditor.ExitAction());
/* edit.add(textComp.getActionMap().get(DefaultEditorKit.cutAction));
edit.add(textComp.getActionMap().get(DefaultEditorKit.copyAction));
edit.add(textComp.getActionMap().get(DefaultEditorKit.pasteAction));
edit.add(textComp.getActionMap().get(DefaultEditorKit.selectAllAction));*/
for (int i = 0; i < count; i++) {
edit.add(textComp2[i].getActionMap().get(DefaultEditorKit.cutAction));
edit.add(textComp2[i].getActionMap().get(DefaultEditorKit.copyAction));
edit.add(textComp2[i].getActionMap().get(DefaultEditorKit.pasteAction));
edit.add(textComp2[i].getActionMap().get(DefaultEditorKit.selectAllAction));
}
return menubar;
}
// Subclass can override to use a different open action.
protected Action getOpenAction() {
return openAction;
}
// Subclass can override to use a different save action.
protected Action getSaveAction() {
return saveAction;
}
//protected JTextComponent getTextComponent() { return textComp; }
// ********** ACTION INNER CLASSES ********** //
// A very simple exit action
public class ExitAction extends AbstractAction {
public ExitAction() {
super("Exit");
}
public void actionPerformed(ActionEvent ev) {
System.exit(0);
}
}
// An action that opens an existing file
class OpenAction extends AbstractAction {
public OpenAction() {
super("Open", new ImageIcon("icons/open.gif"));
}
// Query user for a filename and attempt to open and read the file into the
// text component.
public void actionPerformed(ActionEvent ev) {
JFileChooser chooser = new JFileChooser();
if (chooser.showOpenDialog(SimpleEditor.this)
!= JFileChooser.APPROVE_OPTION) {
return;
}
File file = chooser.getSelectedFile();
if (file == null) {
return;
}
FileReader reader = null;
try {
reader = new FileReader(file);
//textComp.read(reader, null);
for (int i = 0; i < count; i++) {
textComp2[i].read(reader, null);
}
} catch (IOException ex) {
JOptionPane.showMessageDialog(SimpleEditor.this,
"File Not Found", "ERROR", JOptionPane.ERROR_MESSAGE);
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException x) {
}
}
}
}
}
// An action that saves the document to a file
class SaveAction extends AbstractAction {
public SaveAction() {
super("Save", new ImageIcon("icons/save.gif"));
}
// Query user for a filename and attempt to open and write the text
// component’s content to the file.
public void actionPerformed(ActionEvent ev) {
JFileChooser chooser = new JFileChooser();
if (chooser.showSaveDialog(SimpleEditor.this)
!= JFileChooser.APPROVE_OPTION) {
return;
}
File file = chooser.getSelectedFile();
if (file == null) {
return;
}
FileWriter writer = null;
try {
writer = new FileWriter(file);
//textComp.write(writer);
for (int i = 0; i < count; i++) {
textComp2[i].write(writer);
}
} catch (IOException ex) {
JOptionPane.showMessageDialog(SimpleEditor.this,
"File Not Saved", "ERROR", JOptionPane.ERROR_MESSAGE);
} finally {
if (writer != null) {
try {
writer.close();
} catch (IOException x) {
}
}
}
}
}
}
But, my code have some error like this:
Exception in thread "main" java.lang.NullPointerException
- at SimpleEditor.makeActionsPretty(SimpleEditor.java:101)
- at SimpleEditor.<init>(SimpleEditor.java:29)
- at SimpleEditor.main(SimpleEditor.java:19)
Can anybody help me as soon as possible?

The array JTextComponent[] has different sizes at different times, but an object in the array defaults to null until you change it:
textComp2[i] = new JTextField("Hello");

JPanel elements are not appearing

I'm using the Swing library to ask a user for their zipcode, but all that is appearing is a box, without the text box, or any of the other elements that I've added in (see code). Also, you likely need to know that I'm trying to get the int AskZip() in my public static void main(String[] args) method.
private static int zip;
public static int AskZip() {
JFrame zaWindow = new JFrame("What Zipcode");
zaWindow.setSize(200, 300);
JPanel jp = new JPanel();
final JTextField tf = new JTextField("Enter Zip Here");
JLabel label = new JLabel();
JButton button = new JButton("Get Weather");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String sZip = tf.getText();
int rZip = 0;
try {
if (sZip.length() != 5) {
JOptionPane.showMessageDialog(null, "Invalid zipcode!", "Error", JOptionPane.ERROR_MESSAGE);
} else {
rZip = Integer.parseInt(sZip);
}
} catch (NumberFormatException arg) {
JOptionPane.showMessageDialog(null, "Invalid zipcode!", "Error", JOptionPane.ERROR_MESSAGE);
}
zip = rZip;
}
});
label.setText("What is your zipcode?");
jp.add(label);
jp.add(tf);
jp.add(button);
zaWindow.add(jp);
return zip;
}

JFrame zaWindow..
This should be a modal dialog or a JOptionPane. E.G. This country has 3 states, each with 10 postcodes.
import java.awt.*;
import java.util.ArrayList;
import javax.swing.*;
import javax.swing.event.ChangeListener;
class ZipQuery {
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
ZipNumberModel znm = new ZipNumberModel();
JSpinner zip = new JSpinner(znm);
JOptionPane.showMessageDialog(null, zip, "Enter Zipcode", JOptionPane.QUESTION_MESSAGE);
System.out.println("User chose " + znm.getValue());
}
};
// Swing GUIs should be created and updated on the EDT
// http://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html
SwingUtilities.invokeLater(r);
}
}
class ZipNumberModel extends SpinnerNumberModel {
private ArrayList<Integer> zipCodes;
private int index = 0;
ZipNumberModel() {
zipCodes = new ArrayList<Integer>();
int zip = 10000;
for (int jj = 1; jj < 4; jj++) {
for (int ii = jj * zip; ii < jj * zip + 10; ii++) {
zipCodes.add(new Integer(ii));
}
}
}
#Override
public Object getValue() {
return zipCodes.get(index);
}
#Override
public Object getNextValue() {
if (index < zipCodes.size()-1) {
index++;
} else {
index = 0;
}
return zipCodes.get(index);
}
#Override
public Object getPreviousValue() {
if (index > 0) {
index--;
} else {
index = zipCodes.size()-1;
}
return zipCodes.get(index);
}
}

drag and drop files from OS into JTable java

Can someone show me what I'm doing wrong? I was able to get drag and drop working with a regular panel but now trying with a table and I can't sort it out. I'm getting confused with the Points and DropTargets. Dont mind the "Add" button. I feel like I need to deal with the DnD first.
public class Table extends JFrame implements ActionListener {
private JTable table;
private JScrollPane scroll;
private JButton add;
private JFileChooser choose;
private JMenuBar menubar;
private JMenu menu;
private JMenuItem file;
private DefaultTableModel tm = new DefaultTableModel(new String[] { "File",
"File Type", "Size", "Status" }, 2);
public Table() {
// String column [] = {"Filename ","File Type", "Size", "Status" };
/*
* Object[][] data = { {"File1", ".jpg","32 MB", "Not Processed"},
* {"File2", ".txt"," 5 Kb", "Not Processed"}, {"File3", ".doc","3 Kb",
* "Not Processed"},
* };
*/
table = new JTable();
table.setModel(tm);
table.setFillsViewportHeight(true);
table.setPreferredSize(new Dimension(500, 300));
scroll = new JScrollPane(table);
table.setDropTarget(new DropTarget() {
#Override
public synchronized void drop(DropTargetDropEvent dtde) {
Point point = dtde.getLocation();
int column = table.columnAtPoint(point);
int row = table.rowAtPoint(point);
dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
Transferable t = dtde.getTransferable();
List fileList = null;
try {
fileList = (List) t
.getTransferData(DataFlavor.javaFileListFlavor);
} catch (UnsupportedFlavorException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
File f = (File) fileList.get(0);
table.setValueAt(f.getAbsolutePath(), row, column);
table.setValueAt(f.length(), row, column + 1);
super.drop(dtde);
}
});
scroll.setDropTarget(new DropTarget() {
#Override
public synchronized void drop(DropTargetDropEvent dtde) {
Point point = dtde.getLocation();
int column = table.columnAtPoint(point);
int row = table.rowAtPoint(point);
dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
Transferable t = dtde.getTransferable();
List fileList = null;
try {
fileList = (List) t
.getTransferData(DataFlavor.javaFileListFlavor);
} catch (UnsupportedFlavorException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
File f = (File) fileList.get(0);
table.setValueAt(f.getAbsolutePath(), row, column);
table.setValueAt(f.length(), row, column + 1);
// handle drop outside current table (e.g. add row)
super.drop(dtde);
}
});
add(scroll, BorderLayout.CENTER);
menubar = new JMenuBar();
menu = new JMenu("File");
file = new JMenuItem("file");
menu.add(file);
// menubar.add(menu);
add(menu, BorderLayout.NORTH);
ImageIcon icon = new ImageIcon("lock_icon.png");
add = new JButton("Add", icon);
add.addActionListener(this);
JFileChooser choose = new JFileChooser();
choose.addActionListener(this);
}
#Override
public void actionPerformed(ActionEvent e) {
JButton clicked = (JButton) e.getSource();
int returnValue = 0;
if (clicked == add) {
choose = new JFileChooser();
choose.showOpenDialog(null);
if (returnValue == JFileChooser.APPROVE_OPTION) {
File file = choose.getSelectedFile();
file.getAbsolutePath();
}
}
}
public static void main(String[] args) {
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
Table t = new Table();
t.setDefaultCloseOperation(EXIT_ON_CLOSE);
t.pack();
t.setSize(600, 200);
t.setVisible(true);
t.setTitle("ZipLock");
t.setIconImage(null);
}
});
}
}

I personally would ditch the drop target on the scroll pane, it's going to cause you to many problems.
Your drop method is a little queezy...
This is a bad idea....
List fileList = null;
try {
fileList = (List) t
.getTransferData(DataFlavor.javaFileListFlavor);
} catch (UnsupportedFlavorException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
File f = (File) fileList.get(0);
table.setValueAt(f.getAbsolutePath(), row, column);
table.setValueAt(f.length(), row, column + 1);
Basically, you try and extract the file list from the transferable, and regardless of the success of the operation, you try and use it ?! You do no validation of the returned value at all...
Your drop code generally doesn't really care about what column the drop occurred on, as you have name and size columns already, so I'd actually ignore that altogether.
As for the row, now you have two choices. Either you add a new row when the user doesn't drop on an existing one or you reject the attempt.
Reject drag's "outside" of table
(Or reject drags that don't call over an existing row)
To reject the operation while the user is dragging, you need to override the dragOver method...
#Override
public synchronized void dragOver(DropTargetDragEvent dtde) {
Point point = dtde.getLocation();
int row = table.rowAtPoint(point);
if (row < 0) {
dtde.rejectDrag();
table.clearSelection();
} else {
dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
table.setRowSelectionInterval(row, row);
}
}
Now, I'm been a little smart here (and not in the clever way). Basically, if the user has dragged over a row, I've highlighted it. This makes it a little more obvious where the drop is going.
In your drop method, I would also make some additional checks...
#Override
public synchronized void drop(DropTargetDropEvent dtde) {
Point point = dtde.getLocation();
int row = table.rowAtPoint(point);
if (row >= 0) {
if (dtde.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
Transferable t = dtde.getTransferable();
List fileList = null;
try {
fileList = (List) t.getTransferData(DataFlavor.javaFileListFlavor);
if (fileList.size() > 0) {
table.clearSelection();
Point point = dtde.getLocation();
int row = table.rowAtPoint(point);
DefaultTableModel model = (DefaultTableModel) table.getModel();
model.setValueAt(f.getAbsolutePath(), row, 0);
model.setValueAt(f.length(), row, 2);
}
} catch (UnsupportedFlavorException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
} else {
dtde.rejectDrop();
}
} else {
dtde.rejectDrop();
}
}
Accept Drag's "outside" of the table
The process is relativly the same, except now we can throw away the conditions that would have otherwise caused us to reject the drag/drop (obviously)
#Override
public synchronized void dragOver(DropTargetDragEvent dtde) {
Point point = dtde.getLocation();
int row = table.rowAtPoint(point);
if (row < 0) {
table.clearSelection();
} else {
table.setRowSelectionInterval(row, row);
}
dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
}
And the drop method
#Override
public synchronized void drop(DropTargetDropEvent dtde) {
if (dtde.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
Transferable t = dtde.getTransferable();
List fileList = null;
try {
fileList = (List) t.getTransferData(DataFlavor.javaFileListFlavor);
if (fileList.size() > 0) {
table.clearSelection();
Point point = dtde.getLocation();
int row = table.rowAtPoint(point);
DefaultTableModel model = (DefaultTableModel) table.getModel();
for (Object value : fileList) {
if (value instanceof File) {
File f = (File) value;
if (row < 0) {
System.out.println("addRow");
model.addRow(new Object[]{f.getAbsolutePath(), "", f.length(), "", ""});
} else {
System.out.println("insertRow " + row);
model.insertRow(row, new Object[]{f.getAbsolutePath(), "", f.length(), "", ""});
row++;
}
}
}
}
} catch (UnsupportedFlavorException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} else {
dtde.rejectDrop();
}
}
Note. This will insert rows at the drop point, push all the existing rows down OR if not dropped on an existing row, will add them to the end...
TEST CODE
This a full running example I used to test the code...
public class DropTable {
public static void main(String[] args) {
new DropTable();
}
public DropTable() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new DropPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class DropPane extends JPanel {
private JTable table;
private JScrollPane scroll;
private DefaultTableModel tm = new DefaultTableModel(new String[]{"File", "File Type", "Size", "Status"}, 0);
public DropPane() {
table = new JTable();
table.setShowGrid(true);
table.setShowHorizontalLines(true);
table.setShowVerticalLines(true);
table.setGridColor(Color.GRAY);
table.setModel(tm);
table.setFillsViewportHeight(true);
table.setPreferredSize(new Dimension(500, 300));
scroll = new JScrollPane(table);
table.setDropTarget(new DropTarget() {
#Override
public synchronized void dragOver(DropTargetDragEvent dtde) {
Point point = dtde.getLocation();
int row = table.rowAtPoint(point);
if (row < 0) {
table.clearSelection();
} else {
table.setRowSelectionInterval(row, row);
}
dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
}
#Override
public synchronized void drop(DropTargetDropEvent dtde) {
if (dtde.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
Transferable t = dtde.getTransferable();
List fileList = null;
try {
fileList = (List) t.getTransferData(DataFlavor.javaFileListFlavor);
if (fileList.size() > 0) {
table.clearSelection();
Point point = dtde.getLocation();
int row = table.rowAtPoint(point);
DefaultTableModel model = (DefaultTableModel) table.getModel();
for (Object value : fileList) {
if (value instanceof File) {
File f = (File) value;
if (row < 0) {
model.addRow(new Object[]{f.getAbsolutePath(), "", f.length(), "", ""});
} else {
model.insertRow(row, new Object[]{f.getAbsolutePath(), "", f.length(), "", ""});
row++;
}
}
}
}
} catch (UnsupportedFlavorException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
} else {
dtde.rejectDrop();
}
}
});
add(scroll, BorderLayout.CENTER);
}
}
}

Nimbus L & F: Setting different background colors of a Check-Boxes in a CheckBox List

I had a list of check-boxes and I want to set different colors on each check-box.
Following code does not change the background color
checkBox[i] = new JCheckBox();
checkBox[i].setEnabled(false);
checkBox[i].setBackground(Color.GREEN);
Kindly let me know way of setting background color

for example
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.event.*;
public class JListDisabledItemDemo implements ItemListener, Runnable {
private JFrame f = new JFrame("Colors");
private static final String ITEMS[] = {" black ", " blue ", " green ",
" orange ", " purple ", " red ", " white ", " yellow "};
private JList jList;
private JCheckBox[] checkBoxes;
private boolean[] enabledFlags;
#Override
public void run() {
JPanel pnlEnablers = new JPanel(new GridLayout(0, 1));
pnlEnablers.setBorder(BorderFactory.createTitledBorder("Enabled Items"));
checkBoxes = new JCheckBox[ITEMS.length];
enabledFlags = new boolean[ITEMS.length];
for (int i = 0; i < ITEMS.length; i++) {
checkBoxes[i] = new JCheckBox(ITEMS[i]);
checkBoxes[i].setSelected(true);
checkBoxes[i].addItemListener(this);
enabledFlags[i] = true;
pnlEnablers.add(checkBoxes[i]);
}
jList = new JList(ITEMS);
jList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
jList.setSelectionModel(new DisabledItemSelectionModel());
jList.setCellRenderer(new DisabledItemListCellRenderer());
jList.addListSelectionListener(new ListSelectionListener() {
#Override
public void valueChanged(ListSelectionEvent e) {
if (!e.getValueIsAdjusting()) {
System.out.println("selection");
}
}
});
JScrollPane scroll = new JScrollPane(jList);
scroll.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
scroll.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
Container contentPane = f.getContentPane();
contentPane.setLayout(new GridLayout(1, 2));
contentPane.add(pnlEnablers);
contentPane.add(scroll);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setLocation(240, 280);
UIManager.put("List.background", Color.lightGray);
UIManager.put("List.selectionBackground", Color.orange);
UIManager.put("List.selectionForeground", Color.blue);
UIManager.put("Label.disabledForeground", Color.magenta);
SwingUtilities.updateComponentTreeUI(f);
f.pack();
javax.swing.SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
f.setVisible(true);
}
});
}
#Override
public void itemStateChanged(ItemEvent event) {
JCheckBox checkBox = (JCheckBox) event.getSource();
int index = -1;
for (int i = 0; i < ITEMS.length; i++) {
if (ITEMS[i].equals(checkBox.getText())) {
index = i;
break;
}
}
if (index != -1) {
enabledFlags[index] = checkBox.isSelected();
jList.repaint();
}
}
public static void main(String args[]) {
try {
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
System.out.println(info.getName());
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (UnsupportedLookAndFeelException e) {
// handle exception
} catch (ClassNotFoundException e) {
// handle exception
} catch (InstantiationException e) {
// handle exception
} catch (IllegalAccessException e) {
// handle exception
}
SwingUtilities.invokeLater(new JListDisabledItemDemo());
}
private class DisabledItemListCellRenderer extends DefaultListCellRenderer {
private static final long serialVersionUID = 1L;
#Override
public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
Component comp = super.getListCellRendererComponent(list, value, index, false, false);
JComponent jc = (JComponent) comp;
if (enabledFlags[index]) {
if (isSelected & cellHasFocus) {
comp.setForeground(Color.black);
comp.setBackground(Color.red);
} else {
comp.setBackground(Color.white);
comp.setForeground(Color.black);
}
if (!isSelected) {
if ((value.toString()).trim().equals("yellow")) {
comp.setForeground(Color.blue);
comp.setBackground(Color.yellow);
} else if ((value.toString()).trim().equals("black")) {
comp.setForeground(Color.red);
comp.setBackground(Color.black);
}else if ((value.toString()).trim().equals("orange")) {
comp.setForeground(Color.blue);
comp.setBackground(Color.orange);
}
}
return comp;
}
comp.setEnabled(false);
return comp;
}
}
private class DisabledItemSelectionModel extends DefaultListSelectionModel {
private static final long serialVersionUID = 1L;
#Override
public void setSelectionInterval(int index0, int index1) {
if (enabledFlags[index0]) {
super.setSelectionInterval(index0, index0);
} else {
/*The previously selected index is before this one,
* so walk forward to find the next selectable item.*/
if (getAnchorSelectionIndex() < index0) {
for (int i = index0; i < enabledFlags.length; i++) {
if (enabledFlags[i]) {
super.setSelectionInterval(i, i);
return;
}
}
} /*
* Otherwise, walk backward to find the next selectable item.
*/ else {
for (int i = index0; i >= 0; i--) {
if (enabledFlags[i]) {
super.setSelectionInterval(i, i);
return;
}
}
}
}
}
}
}

Try setting your CheckBox Opacity to true.
myCheckBox.setOpaque(true);