Java 运行 JPanel 表单
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Running a JPanel Form
提问by User
I am beginner in java. I created a JPanelform in java (NetBeans). then, i defined some actions such as mathematical calculations. When i ran my project, i did not get any error, but i could not see the JPanelform in the running time. because i did not define jform in main class. how can i define JPanelform in main class to show me JPanelform in running time.
我是java初学者。我JPanel在 java (NetBeans) 中创建了一个表单。然后，我定义了一些操作，例如数学计算。当我运行我的项目时，我没有收到任何错误，但是我JPanel在运行时看不到表单。因为我没有在主类中定义 jform。我如何JPanel在主类中定义表单JPanel以在运行时向我显示表单。
public class NewJPanel extends javax.swing.JPanel {
public NewJPanel() {
initComponents();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jTextField1 = new javax.swing.JTextField();
jTextField2 = new javax.swing.JTextField();
jTextField3 = new javax.swing.JTextField();
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
jButton3 = new javax.swing.JButton();
jButton4 = new javax.swing.JButton();
jButton5 = new javax.swing.JButton();
jLabel1.setText("First Number:");
jLabel2.setText("Second Number:");
jLabel3.setText("Result:");
jButton1.setText("Add");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jButton2.setText("Subtract");
jButton2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});
jButton3.setText("Multiply");
jButton3.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton3ActionPerformed(evt);
}
});
jButton4.setText("Divide");
jButton4.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton4ActionPerformed(evt);
}
});
jButton5.setText("Clear");
jButton5.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton5ActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
this.setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(66, 66, 66)
.addComponent(jButton1)
.addGap(45, 45, 45)
.addComponent(jButton2)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 69, Short.MAX_VALUE)
.addComponent(jButton3)
.addGap(27, 27, 27))
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(39, 39, 39)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel1)
.addComponent(jLabel2)
.addComponent(jLabel3))
.addGap(88, 88, 88)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(jTextField1, javax.swing.GroupLayout.DEFAULT_SIZE, 77, Short.MAX_VALUE)
.addComponent(jTextField2)
.addComponent(jTextField3)))
.addGroup(layout.createSequentialGroup()
.addGap(120, 120, 120)
.addComponent(jButton4)
.addGap(45, 45, 45)
.addComponent(jButton5)))
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(39, 39, 39)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(jTextField1, 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(jLabel2)
.addComponent(jTextField2, 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(jLabel3)
.addComponent(jTextField3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(34, 34, 34)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jButton2)
.addComponent(jButton3))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton4)
.addComponent(jButton5))
.addContainerGap(67, Short.MAX_VALUE))
);
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
double num1, num2, result;
num1 = Double.parseDouble(jTextField1.getText());
num2 = Double.parseDouble(jTextField2.getText());
result = num1 + num2;
jTextField3.setText(String.valueOf(result));
}
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
double num1, num2, result;
num1 = Double.parseDouble(jTextField1.getText());
num2 = Double.parseDouble(jTextField2.getText());
result = num1 - num2;
jTextField3.setText(String.valueOf(result));
}
private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
double num1,num2, result;
num1 = Double.parseDouble(jTextField3.getText());
num2 = Double.parseDouble(jTextField2.getText());
result = num1*num2;
jTextField3.setText(String.valueOf(result));
}
private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {
double num1, num2, result;
num1 = Double.parseDouble(jTextField1.getText());
num2 = Double.parseDouble(jTextField2.getText());
result = num1 / num2;
}
private void jButton5ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField1.setText("");
jTextField2.setText("");
jTextField3.setText("");
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JButton jButton3;
private javax.swing.JButton jButton4;
private javax.swing.JButton jButton5;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JTextField jTextField1;
private javax.swing.JTextField jTextField2;
private javax.swing.JTextField jTextField3;
// End of variables declaration
}
采纳答案by Paul Samsotha
JPanelis not a runnable class without a top-level container like JFrameand you need a mainmethod. Instead of creating JPanelform, you should have created a JFrameform that has a mainmethod auto-generated for you. It looks like you are using Netbeans GUI Builder. Just open a new JFrameform. And you can just add the JPanelform to the JFrameform.
JPanel不是一个没有顶级容器的可运行类，比如JFrame你需要一个main方法。JPanel您应该创建一个JFrame具有main自动生成方法的表单，而不是创建表单。看起来您正在使用 Netbeans GUI Builder。只需打开一个新JFrame表格。您可以将JPanel表单添加到JFrame表单中。
With NetBeans desing view, you can just drag and drop your JPanelform to you JFrameform, as seen here
与NetBeans德兴视图，你可以拖放JPanel的形式给你JFrame形成，因为看到这里
Also to explicitly specify the Main class of a project, see here
另外要明确指定项目的 Main 类，请参见此处
回答by Atakan Yildirim
JFrame frameName = new JFrame();
frameName.setVisible(true);
//Now add your JPanel (JPanel yourJPanelName = new JPanel();)
frameName.add(yourJPanelName);
You can work with JFrame.
您可以使用 JFrame。
