将数据传递到打开的JFrame

Question

我正在使用两个JFrame，POS和金额。当我单击POS框架上的“值”按钮时，它将调用“金额”类供我在其中输入value（＃），而当我单击ENTER时，这些值应被转回到POS框架中的文本区域。通过创建POS jframe的新对象，我可以使文本出现在文本区域中，我要做的是将值放回到已经打开的原始POS框架中。

请参见下面的代码...

 public class Amounts extends javax.swing.JFrame {
String val; 
public Amounts(){
     initComponents(); 
}
public Amounts(String AmtVal) {

    this.val = AmtVal;
    String getValue = txtField.getText();
    txtField.setText(val + getValue);
 }
 private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:  

    String Enternum = txtField.getText();

            if (Enternum == "")
            {
                txtField.setText(jButton1.getText());
            }
        else {
             Enternum = txtField.getText() + jButton1.getText();
                txtField.setText(Enternum);
            }
          } 

   private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:  

    String Enternum = txtField.getText();

            if (Enternum == "")
            {
                txtField.setText(jButton2.getText());
            }
        else {
             Enternum = txtField.getText() + jButton2.getText();
                txtField.setText(Enternum);
            }
          } 
       private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:  

    String Enternum = txtField.getText();

            if (Enternum == "")
            {
                txtField.setText(jButton3.getText());
            }
        else {
             Enternum = txtField.getText() + jButton3.getText();
                txtField.setText(Enternum);
            }
          } 
     private void jEnterActionPerformed(java.awt.event.ActionEvent evt) {                                       
     // TODO add your handling code here:
      String data =  txtField.getText();

     new POS_System(data).setVisible(true);
 }  

  // Variables declaration - do not modify                     
private javax.swing.JButton jEnter;
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton3;
private javax.swing.JButton jButton4;
}

POS类代码：

public class POS_System extends javax.swing.JFrame {
 public POS_System() {
    initComponents();
}

String val ="";
public POS_System(String amt) {
    initComponents();
    this.val = amt;

    jTextArea1.setText(amt);
}

 private void jValueActionPerformed(java.awt.event.ActionEvent evt) {                                      
    // TODO add your handling code here:

    Amounts at = new Amounts ();
    at.setVisible(true);
    at.setLocationRelativeTo(null);
    at.txtField.getText();
    jTextArea1.setText(at.txtField.getText());      
}  

  // Variables declaration - do not modify                     
   private javax.swing.JButton jTextArea1;
   private javax.swing.JButton jEnter;