Java弹簧布局管理器使用方法详解

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：

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);
	}

}

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。

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