Popup and PopupFactory are a part of the Java Swing library. Popups are used when we want to display to the user a Component on the top of all the other Components in that particular containment hierarchy. PopupFactory is the class that is used to create popups. Popups have a very small life cycle, and generally are lightweight components having limited sub-components.
Constructor for the class are :
- PopupFactory(): creates an object for popup factory
Commonly used methods:
method | explanation |
---|---|
getPopup(Component o, Component c, int x, int y) | Creates a Popup for the Component o containing the Component c at a location x, y on the owner component. |
hide() | Hides and disposes of the Popup. |
show() | Makes the Popup visible. |
Below programs will illustrate the use of a popup:
- Java Program to create a popup and display it on a parent frame: We create a popup p by creating a popup factory and using the function getpopup() which returns a popup. We add this popup to a frame f titled “pop” we will create a label and add t to a container panel p2 and set the background of panel p2 using setBackground() function. We will add the container panel p2 to the popup. We will also create a button b titled “click” added with an action listener and displays the popup when the button is pressed. The button b is added to a panel and the panel is added to the frame. Frame is set to the size 400,400 using setSize(400,400). Finally, the frame is displayed using show() function.
Java
// Java Program to create a popup and display // it on a parent frame import javax.swing.*; import java.awt.*; import java.awt.event.*; class pop extends JFrame implements ActionListener { // popup Popup p; // constructor pop() { // create a frame JFrame f = new JFrame( "pop" ); // create a label JLabel l = new JLabel( "This is a popup" ); f.setSize( 400 , 400 ); PopupFactory pf = new PopupFactory(); // create a panel JPanel p2 = new JPanel(); // set Background of panel p2.setBackground(Color.red); p2.add(l); // create a popup p = pf.getPopup(f, p2, 180 , 100 ); // create a button JButton b = new JButton( "click" ); // add action listener b.addActionListener( this ); // create a panel JPanel p1 = new JPanel(); p1.add(b); f.add(p1); f.show(); } // if the button is pressed public void actionPerformed(ActionEvent e) { p.show(); } // main class public static void main(String args[]) { pop p = new pop(); } } |
- Output:
- Java Program to create a popup (add a panel) and display it on a parent frame and also add an action listener to the popup: We create a popup p by creating a popup factory and using the function getpopup() which returns a popup. We will set the look and feel to System look and feel. We add this popup to a frame f titled “pop”, we will create a label and a button b19 titled “OK”( we will set the font of the label to a specified font object) and add it to a container panel p2 and set the background of panel p2 using setBackground() function. We will add the container panel p2 to the popup. We will also create a button b titled “click” added with an action listener and displays the popup when the button is pressed. The button b is added to a panel and the panel is added to the frame. Frame is set to the size 400,400 using setSize(400,400). finally, the frame is displayed using show() function.
Java
// Java Program to create a popup (add a panel) and // display it on a parent frame and also // add action listener to the popup import javax.swing.*; import java.awt.*; import java.awt.event.*; class pop1 extends JFrame implements ActionListener { // popup Popup po; // frame JFrame f; // panel JPanel p; // popupfactory PopupFactory pf; // constructor pop1() { // create a frame f = new JFrame( "pop" ); f.setSize( 400 , 400 ); pf = new PopupFactory(); // create a label JLabel l = new JLabel( "This is a popup menu" ); // create a new button JButton b19 = new JButton( "OK" ); // add action listener b19.addActionListener( this ); try { // set windows look and feel UIManager.setLookAndFeel(UIManager. getSystemLookAndFeelClassName()); } catch (Exception e) { } // create a panel p = new JPanel(); p.setBackground(Color.blue); // create a font Font fo = new Font( "BOLD" , 1 , 14 ); l.setFont(fo); // add contents to panel p.add(l); p.add(b19); p.setLayout( new GridLayout( 2 , 1 )); // create a popup po = pf.getPopup(f, p, 180 , 100 ); // create a button JButton b = new JButton( "click" ); // add action listener b.addActionListener( this ); // create a panel JPanel p1 = new JPanel(); p1.add(b); f.add(p1); f.show(); } // if the button is pressed public void actionPerformed(ActionEvent e) { String d = e.getActionCommand(); // if ok button is pressed hide the popup if (d.equals( "OK" )) { po.hide(); // create a popup po = pf.getPopup(f, p, 180 , 100 ); } else po.show(); } // main class public static void main(String args[]) { pop1 p = new pop1(); } } |
- Output: