由 SpringLayout 类实现的布局管理器称为弹簧布局管理器。利用该布局管理器管理组件，当改变窗体的大小时，能够在不改变组件间相对位置的前提下自动调整组件大小，使组件依旧布满整个窗体，从而保证了窗体的整体效果。下面，通过一个实例来看看弹簧布局管理器的使用方法和效果。
弹簧布局管理器以容器和组件的边缘为操作对象，通过为组件和容器边缘以及组件和组件边缘建立约束，实现对组件布局的管理。通过方法 putConstraint(String e1,Conponet c1,int pad,String e2,Componet c2)可以为各边之间建立约束，该方法的入口参数说明如下：
c1：需要参考的组件对象；
c2：需要参考的组件对象的具体需要参考的边；
e1：被参考的组件对象；
e2：被参考的组件对象的具体被参考的边；
pad：两条边之间的距离，即两个组件之间的间距。
有点绕，其实很好理解。
实例1：使用弹簧布局管理器。
本实例利用弹簧布局管理器实现窗体，在调整窗体的大小后，组件仍会布满整个窗体，并且组件间的相对位置并不会改变。源码：
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import java.awt.Container;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.Spring;
import javax.swing.SpringLayout;
public class SpringLayout_3 extends JFrame {
private static final long serialVersionUID = -6045918631932051025L;
public SpringLayout_3() {
// TODO Auto-generated constructor stub
Container container = getContentPane();
SpringLayout springLayout = new SpringLayout();
container.setLayout(springLayout);
JLabel topicLabel = new JLabel("主题 :");
JLabel contentLabel = new JLabel("内容 :");
final JTextField textField = new JTextField(30);
JTextArea textArea = new JTextArea(3, 30);
JScrollPane scrollPane = new JScrollPane();
scrollPane.setViewportView(textArea);
textArea.setLineWrap(true);
final JButton confirmButton = new JButton("取消");
JButton cancelButton = new JButton("确认");
Spring st = Spring.constant(10);
Spring st2 = Spring.constant(30);
container.add(topicLabel);
springLayout.putConstraint(SpringLayout.NORTH, topicLabel, st,
SpringLayout.NORTH, container);
springLayout.putConstraint(SpringLayout.WEST, topicLabel, st,
SpringLayout.WEST, container);
container.add(textField);
springLayout.putConstraint(SpringLayout.WEST, textField, st2,
SpringLayout.EAST, topicLabel);
springLayout.putConstraint(SpringLayout.NORTH, textField, 0,
SpringLayout.NORTH, topicLabel);
springLayout.putConstraint(SpringLayout.EAST, textField, Spring.minus(st),
SpringLayout.EAST, container);
container.add(contentLabel);
springLayout.putConstraint(SpringLayout.WEST, contentLabel, 0,
SpringLayout.WEST, topicLabel);
springLayout.putConstraint(SpringLayout.NORTH, contentLabel, st,
SpringLayout.SOUTH, topicLabel);
container.add(scrollPane);
springLayout.putConstraint(SpringLayout.NORTH, scrollPane, 0,
SpringLayout.NORTH, contentLabel);
springLayout.putConstraint(SpringLayout.WEST, scrollPane, 0,
SpringLayout.WEST, textField);
springLayout.putConstraint(SpringLayout.EAST, scrollPane, Spring.minus(st),
SpringLayout.EAST, container);
container.add(confirmButton);
springLayout.putConstraint(SpringLayout.SOUTH, scrollPane, Spring.minus(st),
SpringLayout.NORTH, confirmButton);
springLayout.putConstraint(SpringLayout.EAST, confirmButton, Spring.minus(st),
SpringLayout.EAST, container);
springLayout.putConstraint(SpringLayout.SOUTH, confirmButton, Spring.minus(st),
SpringLayout.SOUTH, container);
container.add(cancelButton);
springLayout.putConstraint(SpringLayout.EAST, cancelButton, Spring.minus(st),
SpringLayout.WEST, confirmButton);
springLayout.putConstraint(SpringLayout.NORTH, cancelButton, 0,
SpringLayout.NORTH, confirmButton);
// make the text field focused every time the window is activated
addWindowFocusListener(new WindowAdapter() {
@Override
public void windowGainedFocus(WindowEvent e) {
// TODO Auto-generated method stub
textField.requestFocus();
}
});
}
public static void main(String[] args) {
// TODO Auto-generated method stub
SpringLayout_3 frame = new SpringLayout_3();
frame.setTitle("使用弹簧布局管理器");
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setBounds(100, 100, 600, 300);
}
}
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总结
以上就是弹簧布局管理器的使用方法及实例，喜欢的同学快去试试效果吧。
感谢大家对服务器之家的支持！
原文链接：http://www.xuebuyuan.com/2007237.html