SpringLayout类位置相联子容器，根据一组约束条件。

类声明

以下是声明 javax.swing.SpringLayout类：

public class SpringLayout
   extends Object
      implements LayoutManager2

字段域

以下是javax.swing.SpringLayout类的字段：

• static String BASELINE --指定一个组件的基线。

• static String EAST --指定组件的边界矩形的右边缘。

• static String HEIGHT --指定组件的边界矩形的高度。

• static String HORIZONTAL_CENTER --指定组件的边界矩形的水平中心。

• static String NORTH --指定组件的边界矩形的顶边。

• static String SOUTH --指定组件的边界矩形的底部边缘。

• static String VERTICAL_CENTER --指定组件的边界矩形的垂直中心。

• static String WEST --指定组件的边界矩形的左边缘。

• static String WIDTH --指定组件的边界矩形的宽度。

类构造函数

S.N.	构造函数 & 描述
1	SpringLayout()  Creates a new SpringLayout.

类方法

S.N.	方法 & 描述
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.

方法继承

这个类从以下类继承的方法：

• java.lang.Object

SpringLayout 例子

选择使用任何编辑器创建以下java程序在 D:/ > SWING > com > yiibai > gui >

SwingLayoutDemo.java

package com.yiibai.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 - www.gitbook.net");
      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);  
   } 
}

编译程序，使用命令提示符。到 D:/ > SWING 然后输出以下命令。

D:SWING>javac comyiibaiguiSwingLayoutDemo.java

如果没有错误出现，这意味着编译成功。使用下面的命令来运行程序。

D:SWING>java com.yiibai.gui.SwingLayoutDemo

验证下面的输出