SWING - SpringLayout Class
Introduction
The class SpringLayout positions the children of its associated container according to a set of constraints.
Class declaration
Following is the declaration for javax.swing.SpringLayout class:
public class SpringLayout extends Object implements LayoutManager2
Field
Following are the fields for javax.swing.SpringLayout class:
static String BASELINE -- Specifies the baseline of a component.
static String EAST -- Specifies the right edge of a component's bounding rectangle.
static String HEIGHT -- Specifies the height of a component's bounding rectangle.
static String HORIZONTAL_CENTER -- Specifies the horizontal center of a component's bounding rectangle.
static String NORTH -- Specifies the top edge of a component's bounding rectangle.
static String SOUTH -- Specifies the bottom edge of a component's bounding rectangle.
static String VERTICAL_CENTER -- Specifies the vertical center of a component's bounding rectangle.
static String WEST -- Specifies the left edge of a component's bounding rectangle.
static String WIDTH -- Specifies the width of a component's bounding rectangle.
Class constructors
S.N. | Constructor & Description |
---|---|
1 | SpringLayout() Creates a new SpringLayout. |
Class methods
S.N. | Method & Description |
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1 | void addLayoutComponent(Component component, Object constraints) If constraints is an instance of SpringLayout.Constraints, associates the constraints with the specified component. |
2 | void addLayoutComponent(String name, Component c) Has no effect, since this layout manager does not use a per-component string. |
3 | Spring getConstraint(String edgeName, Component c) Returns the spring controlling the distance between the specified edge of the component and the top or left edge of its parent. |
4 | SpringLayout.Constraints getConstraints(Component c) Returns the constraints for the specified component. |
5 | float getLayoutAlignmentX(Container p) Returns 0.5f (centered). |
6 | float getLayoutAlignmentY(Container p) Returns 0.5f (centered). |
7 | void invalidateLayout(Container p) Invalidates the layout, indicating that if the layout manager has cached information it should be discarded. |
8 | void layoutContainer(Container parent) Lays out the specified container. |
9 | Dimension maximumLayoutSize(Container parent) Calculates the maximum size dimensions for the specified container, given the components it contains. |
10 | Dimension minimumLayoutSize(Container parent) Calculates the minimum size dimensions for the specified container, given the components it contains. |
11 | Dimension preferredLayoutSize(Container parent) Calculates the preferred size dimensions for the specified container, given the components it contains. |
12 | void putConstraint(String e1, Component c1, int pad, String e2, Component c2) Links edge e1 of component c1 to edge e2 of component c2, with a fixed distance between the edges. |
13 | void putConstraint(String e1, Component c1, Spring s, String e2, Component c2) Links edge e1 of component c1 to edge e2 of component c2. |
14 | void removeLayoutComponent(Component c) Removes the constraints associated with the specified component. |
Methods inherited
This class inherits methods from the following classes:
java.lang.Object
SpringLayout Example
Create the following java program using any editor of your choice in say D:/ > SWING > com > tutorialspoint > gui >
SwingLayoutDemo.javapackage com.tutorialspoint.gui; import java.awt.*; import java.awt.event.*; import javax.swing.*; public class SwingLayoutDemo { private JFrame mainFrame; private JLabel headerLabel; private JLabel statusLabel; private JPanel controlPanel; private JLabel msglabel; public SwingLayoutDemo(){ prepareGUI(); } public static void main(String[] args){ SwingLayoutDemo swingLayoutDemo = new SwingLayoutDemo(); swingLayoutDemo.showSpringLayoutDemo(); } private void prepareGUI(){ mainFrame = new JFrame("Java SWING Examples"); mainFrame.setSize(400,400); mainFrame.setLayout(new GridLayout(3, 1)); headerLabel = new JLabel("",JLabel.CENTER ); statusLabel = new JLabel("",JLabel.CENTER); statusLabel.setSize(350,100); mainFrame.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent windowEvent){ System.exit(0); } }); controlPanel = new JPanel(); controlPanel.setLayout(new FlowLayout()); mainFrame.add(headerLabel); mainFrame.add(controlPanel); mainFrame.add(statusLabel); mainFrame.setVisible(true); } private void showSpringLayoutDemo(){ headerLabel.setText("Layout in action: SpringLayout"); SpringLayout layout = new SpringLayout(); JPanel panel = new JPanel(); panel.setLayout(layout); JLabel label = new JLabel("Enter Name: "); JTextField textField = new JTextField("", 15); panel.add(label); panel.add(textField); layout.putConstraint(SpringLayout.WEST, label,5, SpringLayout.WEST, controlPanel); layout.putConstraint(SpringLayout.NORTH, label,5, SpringLayout.NORTH, controlPanel); layout.putConstraint(SpringLayout.WEST, textField,5, SpringLayout.EAST, label); layout.putConstraint(SpringLayout.NORTH, textField,5, SpringLayout.NORTH, controlPanel); layout.putConstraint(SpringLayout.EAST, panel,5, SpringLayout.EAST, textField); layout.putConstraint(SpringLayout.SOUTH, panel,5, SpringLayout.SOUTH, textField); controlPanel.add(panel); mainFrame.setVisible(true); } }
Compile the program using command prompt. Go to D:/ > SWING and type the following command.
D:\SWING>javac com\tutorialspoint\gui\SwingLayoutDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\SWING>java com.tutorialspoint.gui.SwingLayoutDemo
Verify the following output
![SWING SpringLayout](/swing/images/swing_springLayout.jpg)