由 SpringLayout 類實現的布局管理器稱為彈簧布局管理器。利用該布局管理器管理組件，當改變窗體的大小時，能夠在不改變組件間相對位置的前提下自動調整組件大小，使組件依舊布滿整個窗體，從而保證了窗體的整體效果。下面，通過一個實例來看看彈簧布局管理器的使用方法和效果。
彈簧布局管理器以容器和組件的邊緣為操作對象，通過為組件和容器邊緣以及組件和組件邊緣建立約束，實現對組件布局的管理。通過方法 putConstraint(String e1,Conponet c1,int pad,String e2,Componet c2)可以為各邊之間建立約束，該方法的入口參數說明如下：
c1：需要參考的組件對象；
c2：需要參考的組件對象的具體需要參考的邊；
e1：被參考的組件對象；
e2：被參考的組件對象的具體被參考的邊；
pad：兩條邊之間的距離，即兩個組件之間的間距。
有點繞，其實很好理解。
實例1：使用彈簧布局管理器。
本實例利用彈簧布局管理器實現窗體，在調整窗體的大小后，組件仍會布滿整個窗體，并且組件間的相對位置并不會改變。源碼：
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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("主題 :"); JLabel contentLabel = new JLabel("內容 :"); 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("確認"); 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("使用彈簧布局管理器"); frame.setVisible(true); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setBounds(100, 100, 600, 300); }} |
總結
以上就是彈簧布局管理器的使用方法及實例，喜歡的同學快去試試效果吧。
感謝大家對服務器之家的支持！
原文鏈接：http://www.xuebuyuan.com/2007237.html
