Question

我有ClassA进行一些处理，我希望它创建一个弹出Jframe ClassB，显示ClassA计算的一些统计信息。所以我做了这样的事情：

public class MainMenu extends javax.swing.JFrame {

public MainMenu() {
    initComponents();
}

private void initComponents() {

    calculateButton = new javax.swing.JButton();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    calculateButton.setText("Calculate");
    calculateButton.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            calculateButtonActionPerformed(evt);
        }
    });

    pack();
}             

private void calculateButtonActionPerformed(java.awt.event.ActionEvent evt) {                                                
    new ClassA().calculate();
}
public static void main(String args[]) {

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new MainMenu().setVisible(true);
        }
    });
}




public class ClassA {
private int i;
private ClassB classB;
public ClassA(){
    i = 3000;
    classB = new ClassB();
    classB.setVisible(true);


}

public void calculate(){
    int percentComplete;
    for (int j = 0 ; j<i ; j++){
        for (int x = 0; x<100000 ; x++)
            for (int y = 0; y<100000 ; y++)
                for (int z = 0; z<100000 ; z++);
        percentComplete = (int) (100 * (float)j/ (float) i);
        System.out.println(" "+percentComplete);
        classB.setProgress(percentComplete);
    }
}

}

public class ClassB extends javax.swing.JFrame {

public ClassB() {
    initComponents();
}

private void initComponents() {

    jPanel1 = new javax.swing.JPanel();
    jProgressBar1 = new javax.swing.JProgressBar();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jProgressBar1.setStringPainted(true);
    javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addComponent(jProgressBar1, javax.swing.GroupLayout.DEFAULT_SIZE, 370, Short.MAX_VALUE)
            .addContainerGap())
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addGap(39, 39, 39)
            .addComponent(jProgressBar1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(52, 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()
            .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addContainerGap())
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(181, Short.MAX_VALUE))
    );

    pack();
}

public void setProgress(int x){
    jProgressBar1.setValue ( x );
}


private javax.swing.JPanel jPanel1;
private javax.swing.JProgressBar jProgressBar1;

}

我面临的问题是ClassB的JFrame显示为一个空窗口，并且在ClassA的所有进程/计算完成之前不会显示任何内容。然后它显示其内容，但最后更新来自ClassA的数据。任何想法或解决方案？

Answer 1

您没有说明如何调用进行各种计算的ClassA 方法。我只能猜测你在一个事件调度线程中调用它们（有关详细信息，请参阅The Event Dispatch Thread），并且在ClassA完成其处理之前，Java无法呈现任何内容。

如果是这种情况，您应该在其他线程中运行这些计算。最方便的方法是using SwingWorker。

JFrame弹出窗口没有显示内容

1 个答案: