o显示图像
我想通过点击一个button，将图像从networking显示到另一个Jframe中的面板，但每当我点击button，图像加载，在此期间，当前窗体可能会冻结，一旦图像加载显示窗体与图像..我怎样才能避免forms冻结，因为它是非常刺激的情况
我的代码::
我目前的class级
private void btn_TrackbusActionPerformed(java.awt.event.ActionEvent evt) { try { sendMessage("Query,map,$,start,211,Arsenal,!"); System.out.println(receiveMessage()); } catch (UnknownHostException ex) { Logger.getLogger(client_Trackbus.class.getName()).log(Level.SEVERE, null, ex); } catch (IOException ex) { Logger.getLogger(client_Trackbus.class.getName()).log(Level.SEVERE, null, ex); } catch (Exception ex) { Logger.getLogger(client_Trackbus.class.getName()).log(Level.SEVERE, null, ex); } client_trackedbus nextform=new client_trackedbus(planform,connection,packet_receive,packet_send); this.setVisible(false); this.dispose(); nextform.setVisible(true); // TODO add your handling code here: } 我的下一个class，显示图像
public class client_trackedbus extends javax.swing.JFrame { client_planform planform=null; DatagramSocket connection=null; DatagramPacket packet_receive=null; DatagramPacket packet_send=null; JLabel label=null; /** Creates new form client_trackedbus */ public client_trackedbus(client_planform planform,DatagramSocket connection,DatagramPacket packet_receive,DatagramPacket packet_send) { initComponents(); this.planform=planform; this.connection=connection; this.packet_receive=packet_receive; this.packet_send=packet_send; try { displayMap("http://www.huddletogether.com/projects/lightbox2http://img.dovov.comimage-2.jpg", jPanel1, new JLabel()); } catch (MalformedURLException ex) { Logger.getLogger(client_trackedbus.class.getName()).log(Level.SEVERE, null, ex); } } private void displayMap(String url,JPanel panel,JLabel label) throws MalformedURLException{ URL imageurl=new URL(url); Image image=(Toolkit.getDefaultToolkit().createImage(imageurl)); ImageIcon icon = new ImageIcon(image); label.setIcon(icon); panel.add(label); // System.out.println(panel.getSize().width); this.getContentPane().add(panel); } /** This method is called from within the constructor to * initialize the form. * WARNING: Do NOT modify this code. The content of this method is * always regenerated by the Form Editor. */ @SuppressWarnings("unchecked") // <editor-fold defaultstate="collapsed" desc="Generated Code"> private void initComponents() { jPanel1 = new javax.swing.JPanel(); jLabel1 = new javax.swing.JLabel(); btn_Exit = new javax.swing.JButton(); btn_Plan = new javax.swing.JButton(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); setTitle("Public Transport Journey Planner"); javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1); jPanel1.setLayout(jPanel1Layout); jPanel1Layout.setHorizontalGroup( jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 368, Short.MAX_VALUE) ); jPanel1Layout.setVerticalGroup( jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 172, Short.MAX_VALUE) ); jLabel1.setFont(new java.awt.Font("Arial", 1, 18)); jLabel1.setText("Your tracked bus"); btn_Exit.setText("Exit"); btn_Exit.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { btn_ExitActionPerformed(evt); } }); btn_Plan.setText("Plan journey"); btn_Plan.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { btn_PlanActionPerformed(evt); } }); javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); getContentPane().setLayout(layout); layout.setHorizontalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(104, 104, 104) .addComponent(jLabel1)) .addGroup(layout.createSequentialGroup() .addContainerGap() .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)) .addGroup(layout.createSequentialGroup() .addGap(65, 65, 65) .addComponent(btn_Plan) .addGap(65, 65, 65) .addComponent(btn_Exit, javax.swing.GroupLayout.PREFERRED_SIZE, 87, javax.swing.GroupLayout.PREFERRED_SIZE))) .addContainerGap(20, Short.MAX_VALUE)) ); layout.setVerticalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(35, 35, 35) .addComponent(jLabel1) .addGap(18, 18, 18) .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) .addGap(18, 18, 18) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) .addComponent(btn_Exit) .addComponent(btn_Plan)) .addContainerGap(12, Short.MAX_VALUE)) ); pack(); }// </editor-fold> private void btn_ExitActionPerformed(java.awt.event.ActionEvent evt) { // TODO add your handling code here: Exitform(); } private void btn_PlanActionPerformed(java.awt.event.ActionEvent evt) { // TODO add your handling code here: this.setVisible(false); this.dispose(); this.planform.setVisible(true); } private void Exitform(){ this.setVisible(false); this.dispose(); } /** * @param args the command line arguments */ public static void main(String args[]) { java.awt.EventQueue.invokeLater(new Runnable() { public void run() { // new client_trackedbus().setVisible(true); } }); } // Variables declaration - do not modify private javax.swing.JButton btn_Exit; private javax.swing.JButton btn_Plan; private javax.swing.JLabel jLabel1; private javax.swing.JPanel jPanel1; // End of variables declaration }
public class SSBTest extends javax.swing.JFrame { /** Creates new form worker1 */ public SSBTest() { initComponents(); } /** This method is called from within the constructor to * initialize the form. * WARNING: Do NOT modify this code. The content of this method is * always regenerated by the Form Editor. */ @SuppressWarnings("unchecked") // <editor-fold defaultstate="collapsed" desc="Generated Code"> private void initComponents() { jLabel1 = new javax.swing.JLabel(); jPanel1 = new javax.swing.JPanel(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); jLabel1.setText("jLabel1"); javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1); jPanel1.setLayout(jPanel1Layout); jPanel1Layout.setHorizontalGroup( jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addGap(0, 348, Short.MAX_VALUE)); jPanel1Layout.setVerticalGroup( jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addGap(0, 210, Short.MAX_VALUE)); javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); getContentPane().setLayout(layout); layout.setHorizontalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addGroup(layout.createSequentialGroup().addContainerGap(196, Short.MAX_VALUE).addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 182, javax.swing.GroupLayout.PREFERRED_SIZE).addGap(178, 178, 178)).addGroup(layout.createSequentialGroup().addGap(86, 86, 86).addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE).addContainerGap(122, Short.MAX_VALUE))); layout.setVerticalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING).addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup().addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE).addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 40, Short.MAX_VALUE).addComponent(jLabel1).addGap(36, 36, 36))); pack(); }// </editor-fold> /** * @param args the command line arguments */ public static void main(String args[]) { java.awt.EventQueue.invokeLater(new Runnable() { public void run() { final SSBTest ssbTest = new SSBTest(); ssbTest.setVisible(true); ssbTest.execute(); } }); } private void execute() { (new MeaningOfLifeFinder(jLabel1, jPanel1)).execute(); } // Variables declaration - do not modify private javax.swing.JLabel jLabel1; private javax.swing.JPanel jPanel1; // End of variables declaration } class MeaningOfLifeFinder extends SwingWorker<Icon, Object> { JLabel label = null; JPanel panel; MeaningOfLifeFinder(JLabel label, JPanel jpanel) { this.label = label; this.panel = jpanel; } protected Icon doInBackground() throws IOException { URL imageurl; Image image = null; System.out.println("image loading"); imageurl = new URL("http://maps.google.com/maps/api/staticmap" + "?zoom=14&size=512x512&maptype=roadmap" + "&markers=color:green|label:21|-15.0,-150.0&sensor=false"); //image = (Toolkit.getDefaultToolkit().createImage(imageurl)); image = ImageIO.read(imageurl); ImageIcon icon = new ImageIcon(image); System.out.println("image loaded..."); return icon; } @Override protected void done() { try { System.out.println("image adding to label..."); label.setIcon(get()); //panel.add(label); System.out.println("image loaded to label..."); } catch (Exception ignore) { } } // System.out.println(panel.getSize().width); }
正如Swing中的Concurrency文章中所build议的那样，button处理程序的查询可能会阻塞事件分派线程。 使用javax.swing.SwingWorker是在后台加载图像，同时显示进度并保持GUI线程活着的一种方法。
附录：这是加载SO徽标的sscce ：
import java.awt.*; import java.io.IOException; import java.net.URL; import javax.imageio.ImageIO; import javax.swing.*; /** @see http://stackoverflow.com/questions/4530659 */ public class WorkerTest extends javax.swing.JFrame { private JPanel panel = new JPanel(); private JLabel label = new JLabel("Loading..."); public WorkerTest() { this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); label.setHorizontalTextPosition(JLabel.CENTER); label.setVerticalTextPosition(JLabel.BOTTOM); this.add(label); this.pack(); } private void start() { new ImageWorker().execute(); } public static void main(String args[]) { EventQueue.invokeLater(new Runnable() { @Override public void run() { WorkerTest wt = new WorkerTest(); wt.setVisible(true); wt.start(); } }); } class ImageWorker extends SwingWorker<Icon, Void> { private static final String TEST = "Sites/stackoverflow/company/img/logos/so/so-logo.png"; private ImageIcon icon; @Override protected Icon doInBackground() throws IOException { Image image = ImageIO.read(new URL(TEST)); icon = new ImageIcon(image); return icon; } @Override protected void done() { label.setIcon(icon); label.setText("Done"); panel.setPreferredSize(new Dimension( icon.getIconWidth(), icon.getIconHeight())); WorkerTest.this.pack(); } } }
