Java Swing: Wie man GUI dynamisch ändert

Ich muss Komponenten dynamisch hinzufügen. Außerdem muss ich das Layout dynamisch ändern.

Als Referenz ist hier ein Beispiel , das die essentielle Methode validate() . Dieses aufwendigere Beispiel zeigt beide Anforderungen: Es ändert das Layout und fügt Komponenten dynamisch hinzu.

 import java.awt.*; import java.awt.event.ActionEvent; import javax.swing.*; /** @see http://stackoverflow.com/questions/5750068 */ public class DynamicLayout extends JPanel { private static final LayoutManager H = new GridLayout(1, 0); private static final LayoutManager V = new GridLayout(0, 1); public DynamicLayout() { this.setLayout(H); this.setPreferredSize(new Dimension(320, 240)); for (int i = 0; i < 3; i++) { this.add(new JLabel("Label " + String.valueOf(i), JLabel.CENTER)); } } private void display() { JFrame f = new JFrame("DynamicLayout"); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.add(this); JPanel p = new JPanel(); p.add(new JButton(new AbstractAction("Horizontal") { @Override public void actionPerformed(ActionEvent e) { DynamicLayout.this.setLayout(H); DynamicLayout.this.validate(); } })); p.add(new JButton(new AbstractAction("Vertical") { @Override public void actionPerformed(ActionEvent e) { DynamicLayout.this.setLayout(V); DynamicLayout.this.validate(); } })); f.add(p, BorderLayout.SOUTH); f.pack(); f.setLocationRelativeTo(null); f.setVisible(true); } public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { @Override public void run() { new DynamicLayout().display(); } }); } } 

Beispiel für das Ändern des Layouts Dynamisch:

 package swinglayout; import java.awt.BorderLayout; import java.awt.Container; import java.awt.FlowLayout; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; public class LayoutChanger implements ActionListener{ JButton b1; JButton b2; JButton b3; JButton b4; JButton b5; JButton b6; /** This button set the flowlayout on panel2 with left orientation */ JButton flowLayout; /** This button set the Gridlayout of 2,3 grid on panel2 */ JButton gridLayout; /** This button set the Borderlayout on panel2*/ JButton borderLayout; /** * This panel is control panel where we use button to change * layout of another panel */ JPanel panel; /** This panel contain multiple button from b1 to b6 */ JPanel panel2; JFrame frame; public LayoutChanger() { //set Default Look and Feel on frame JFrame.setDefaultLookAndFeelDecorated(true); frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Container con = frame.getContentPane(); con.setLayout(new BorderLayout()); panel = new JPanel(); panel2 = new JPanel(); //This button are used to only showing the layout effect b1 = new JButton("HelloButton1"); b2 = new JButton("HelloButton2"); b3 = new JButton("HelloButton3"); b4 = new JButton("HelloButton4"); b5 = new JButton("HelloButton5"); b6 = new JButton("HelloButton6"); // By default panel have layout panel2.add(b1); panel2.add(b2); panel2.add(b3); panel2.add(b4); panel2.add(b5); panel2.add(b6); // Layout changer button flowLayout = new JButton("FlowLayout"); gridLayout = new JButton("GridLayout"); borderLayout = new JButton("BorderLayout"); //call Action listener on every layout changer button flowLayout.addActionListener(this); gridLayout.addActionListener(this); borderLayout.addActionListener(this); panel.add(flowLayout); panel.add(gridLayout); panel.add(borderLayout); // add layout changer button panel at a top //button panel at the center of container con.add(panel, BorderLayout.PAGE_START); con.add(panel2, BorderLayout.CENTER); frame.setVisible(true); frame.pack(); } public void actionPerformed(ActionEvent e) { //set the flowlayout on panel2 if(e.getSource() == flowLayout) { FlowLayout flow = new FlowLayout(FlowLayout.LEFT); panel2.setLayout(flow); panel2.validate(); } //set the gridlayout on panel2 if(e.getSource() == gridLayout) { GridLayout grid = new GridLayout(2,3); panel2.setLayout(grid); panel2.validate(); } //set the gridlayout but the problem if we don't set the constraint //all button are set on center. So you remove the all button from panel //Then set grid layout on panel and add them with constraints. if(e.getSource() == borderLayout) { panel2.remove(b1); panel2.remove(b2); panel2.remove(b3); panel2.remove(b4); panel2.remove(b5); panel2.remove(b6); BorderLayout border = new BorderLayout(); panel2.setLayout(border); panel2.add(b1,BorderLayout.NORTH); panel2.add(b2,BorderLayout.SOUTH); panel2.add(b3,BorderLayout.EAST); panel2.add(b4,BorderLayout.WEST); panel2.add(b5,BorderLayout.CENTER); panel2.add(b6,BorderLayout.BEFORE_FIRST_LINE); panel2.validate(); } } public static void main(String args[]) { new LayoutChanger(); } } 

Eine Sache, die Sie erinnern, ist, dass Sie neues Layout auf dem Panel nicht vergessen, rufen Sie die Methode validate() auf dem Panel.Wenn Sie diese Methode nicht aufrufen, sehen Sie nicht die Auswirkungen der Änderung im Layout. Wenn Sie den Effekt ohne Aufruf der Methode sehen möchten, müssen Sie die Größe des Rahmens ändern. Sie können dasselbe Layout auch sehr einfach FlowLayout , wie FlowLayout , GridLayout und BoxLayout , aber wenn BorderLayout gesetzt ist, BorderLayout Sie alle Elemente aus dem Panel remove(Component comp) indem Sie remove(Component comp) Methode remove(Component comp) dann die Komponente im Panel nach constraint einfügen