Java Swing MVC Example
In this example we are going to demonstrate Java Swing MVC, The MVC pattern is a model of how a user interface can be structured. Therefore it defines the following 3 elements:
- Model that represents the data for the application.
- View that is the visual representation of that data.
- Controller that takes user input on the view and translates that to changes in the model.
1. MVC Components
1.1. Model
A model is an abstraction of something that is presented to the user. The models provided by Swing fall into two general categories:GUI-state models andapplication-data models. GUI state models are interfaces that define the visual status of a GUI control, such as whether a button is pressed or armed likeButtonModel. Anapplication-data model is an interface that represents some quantifiable data that the UI presents to the user, such as the value of a cell in a table likeTableModel.
1.2. View
The view is a UI component that is responsible for presenting data to the user. Thus it is responsible for all UI dependent issues like layout, drawing, etc.JTable is a good example for the view.
1.3. Controller
A controller encapsulates the application code that is executed in order to an user interaction (mouse motion, mouse click, key press, etc.). Controllers might need input for their execution and they produce output. They read their input from models and update models as result of the execution. In swing a controller is normally implemented by anActionListener orAction.
Now, lets see our concrete Swing MVC example where we have an application that let you filter stocks. The application UI contains a text field where the user can enter a filter string, button to start the filter and table where the filter results are displayed.
2. Swing MVC Example
2.1. Model
We createModel.java class which implements theTableModel interface (or, more likely, subclass theAbstractTableModel class). The job of this TableModel implementation is to serve as the interface between your data and the JTable as a view component. Also, we add a supplementaryConstants.java class contains constants used through our code.
Model.java:
package com.jcg;import javax.swing.table.DefaultTableModel;/** * @author ashraf * */@SuppressWarnings("serial")public class Model extends DefaultTableModel {public Model() {super(Constants.DATA, Constants.TABLE_HEADER);}}Constants.java:
package com.jcg;/** * @author ashraf_sarhan * */public class Constants {public static final Object[] TABLE_HEADER = { "Symbol", "Company Name","Price", "Change", "% Change", "Volume" };public static final Object[][] DATA = {{ "BAC", "Bank of America Corporation", 15.98, 0.14, "+0.88%",32157250 },{ "AAPL", "Apple Inc.", 126.57, -1.97, "-1.54%", 31367143 },{ "ABBV", "AbbVie Inc.", 57.84, -2.43, "-4.03%", 30620258 },{ "ECA", "Encana Corporation", 11.74, -0.53, "-4.33%", 27317436 },{ "VALE", "Vale S.A.", 6.55, -0.33, "-4.80%", 19764400 },{ "FB", "Facebook, Inc.", 81.53, 0.64, "+0.78%", 16909729 },{ "PBR", "Petróleo Brasileiro S.A. - Petrobras", 6.05, -0.12,"-2.02%", 16181759 },{ "NOK", "Nokia Corporation", 8.06, 0.01, "+0.12%", 13611860 },{ "PCYC", "Pharmacyclics Inc.", 254.67, 24.19, "+10.50%", 13737834 },{ "RAD", "Rite Aid Corporation", 7.87, -0.18, "-2.24%", 13606253 } };}2.2. View
We createView.java class which contains our main UI components, aJTextField where the user can enter a filter string,JButton to start the filter and JTable where the filter results are displayed.
View.java:
package com.jcg;import java.awt.Dimension;import javax.swing.BorderFactory;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JPanel;import javax.swing.JScrollPane;import javax.swing.JSplitPane;import javax.swing.JTable;import javax.swing.JTextField;import javax.swing.border.TitledBorder;/** * @author ashraf * */public class View {public View() {// Create views swing UI components JTextField searchTermTextField = new JTextField(26);JButton filterButton = new JButton("Filter");JTable table = new JTable();// Create table modelModel model = new Model();table.setModel(model);// Create controllerController controller = new Controller(searchTermTextField, model);filterButton.addActionListener(controller);// Set the view layoutJPanel ctrlPane = new JPanel();ctrlPane.add(searchTermTextField);ctrlPane.add(filterButton);JScrollPane tableScrollPane = new JScrollPane(table);tableScrollPane.setPreferredSize(new Dimension(700, 182));tableScrollPane.setBorder(BorderFactory.createTitledBorder(BorderFactory.createEtchedBorder(), "Market Movers",TitledBorder.CENTER, TitledBorder.TOP));JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, ctrlPane, tableScrollPane);splitPane.setDividerLocation(35);splitPane.setEnabled(false);// Display it all in a scrolling window and make the window appearJFrame frame = new JFrame("Swing MVC Demo");frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);frame.add(splitPane);frame.pack();frame.setLocationRelativeTo(null);frame.setVisible(true);}}2.3. Controller
We createController.java class which implements the ActionListener interface, it will be invoked as a result of a user’s action on a view (i.e., it will be invoked because of the filter button click).
Controller.java:
package com.jcg;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.JOptionPane;import javax.swing.JTextField;import javax.swing.table.DefaultTableModel;/** * @author ashraf * */public class Controller implements ActionListener {private JTextField searchTermTextField = new JTextField(26);private DefaultTableModel model;public Controller(JTextField searchTermTextField, DefaultTableModel model) {super();this.searchTermTextField = searchTermTextField;this.model = model;}@Overridepublic void actionPerformed(ActionEvent e) {String searchTerm = searchTermTextField.getText();if (searchTerm != null && !"".equals(searchTerm)) {Object[][] newData = new Object[Constants.DATA.length][];int idx = 0;for (Object[] o: Constants.DATA) {if ("*".equals(searchTerm.trim())) {newData[idx++] = o;} else {if(String.valueOf(o[0]).startsWith(searchTerm.toUpperCase().trim())){newData[idx++] = o;}}}model.setDataVector(newData, Constants.TABLE_HEADER);} else {JOptionPane.showMessageDialog(null,"Search term is empty", "Error",JOptionPane.ERROR_MESSAGE);}}}2.4. Running the Swing MVC Example
We createSwingMVCDemo.java class which serve as main class to running our example.
SwingMVCDemo.java:
package com.jcg;import javax.swing.SwingUtilities;/** * @author ashraf_sarhan * */public class SwingMVCDemo {public static void main(String[] args) {SwingUtilities.invokeLater(new Runnable() {public void run() {try {createAndShowGUI();} catch (Exception e) {e.printStackTrace();}}});}public static void createAndShowGUI() throws Exception {new View();}}Output:
3. Download the Source Code
This was an example to show Java Swing MVC.
You can download the full source code of this example here:SwingMVCExampleCode.zip
Thank you!
We will contact you soon.
