o ein Bild anzeigen

Question

Ich möchte ein Bild aus dem Web auf ein Panel in einem anderen Jframe mit einem Klick auf eine Schaltfläche anzeigen, aber jedes Mal, wenn ich auf die Schaltfläche klicke, lädt das Bild und während dieser Zeit friert das aktuelle Formular möglicherweise ein Bild geladen wird das Formular mit dem Bild angezeigt wird .. Wie kann ich die Situation zu vermeiden, wo meine Form erstarrt, da es sehr irritierend ist

Meine Codes ::

Meine aktuelle Klasse

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: 
    }            

Meine nächste Klasse dass zeigt das Bild

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/lightbox2/images/image-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     

} 

Answer 1

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); 
} 

Answer 2

Wie in dem Artikel vorgeschlagen Concurrency in Swing, Ihre Abfrage Tastenhandler den Event Dispatch Thread blockieren könnte. Mit javax.swing.SwingWorker können Sie Bilder im Hintergrund laden, während Sie den Fortschritt anzeigen und den GUI-Thread am Leben erhalten.

Nachtrag: Hier ist ein sscce, die das SO Logo lädt:

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 = 
      "http://cdn.sstatic.net/stackexchange/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(); 
     } 
    } 
}