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📜  Java Swing-JCheckBox

📅  最后修改于: 2020-09-30 05:56:22             🧑  作者: Mango

Java JCheckBox

JCheckBox类用于创建复选框。它用于打开(true)或关闭(false)选项。单击CheckBox会将其状态从“打开”更改为“关闭”，或从“关闭”更改为“打开”。它继承了JToggleButton类。

JCheckBox类声明

我们来看一下javax.swing.JCheckBox类的声明。

public class JCheckBox extends JToggleButton implements Accessible

常用的构造函数：

Constructor Description
JJCheckBox() Creates an initially unselected check box button with no text, no icon.
JChechBox(String s) Creates an initially unselected check box with text.
JCheckBox(String text, boolean selected) Creates a check box with text and specifies whether or not it is initially selected.
JCheckBox(Action a) Creates a check box where properties are taken from the Action supplied.

常用方法：

Methods Description
AccessibleContext getAccessibleContext() It is used to get the AccessibleContext associated with this JCheckBox.
protected String paramString() It returns a string representation of this JCheckBox.

Java JCheckBox示例

import javax.swing.*;
public class CheckBoxExample
{
 CheckBoxExample(){
    JFrame f= new JFrame("CheckBox Example");
    JCheckBox checkBox1 = new JCheckBox("C++");
    checkBox1.setBounds(100,100, 50,50);
    JCheckBox checkBox2 = new JCheckBox("Java", true);
    checkBox2.setBounds(100,150, 50,50);
    f.add(checkBox1);
    f.add(checkBox2);
    f.setSize(400,400);
    f.setLayout(null);
    f.setVisible(true);
 }
public static void main(String args[])
    {
    new CheckBoxExample();
    }}

输出：

带有ItemListener的Java JCheckBox示例

import javax.swing.*;
import java.awt.event.*;  
public class CheckBoxExample  
{  
     CheckBoxExample(){  
        JFrame f= new JFrame("CheckBox Example");  
        final JLabel label = new JLabel();          
        label.setHorizontalAlignment(JLabel.CENTER);  
        label.setSize(400,100);  
        JCheckBox checkbox1 = new JCheckBox("C++");  
        checkbox1.setBounds(150,100, 50,50);  
        JCheckBox checkbox2 = new JCheckBox("Java");  
        checkbox2.setBounds(150,150, 50,50);  
        f.add(checkbox1); f.add(checkbox2); f.add(label);  
        checkbox1.addItemListener(new ItemListener() {  
             public void itemStateChanged(ItemEvent e) {               
                label.setText("C++ Checkbox: "   
                + (e.getStateChange()==1?"checked":"unchecked"));  
             }  
          });  
        checkbox2.addItemListener(new ItemListener() {  
             public void itemStateChanged(ItemEvent e) {               
                label.setText("Java Checkbox: "   
                + (e.getStateChange()==1?"checked":"unchecked"));  
             }  
          });  
        f.setSize(400,400);  
        f.setLayout(null);  
        f.setVisible(true);  
     }  
public static void main(String args[])  
{  
    new CheckBoxExample();  
}  
}

输出：

Java JCheckBox示例：食物订单

import javax.swing.*;
import java.awt.event.*;
public class CheckBoxExample extends JFrame implements ActionListener{
JLabel l;
JCheckBox cb1,cb2,cb3;
JButton b;
CheckBoxExample(){
l=new JLabel("Food Ordering System");
l.setBounds(50,50,300,20);
cb1=new JCheckBox("Pizza @ 100");
cb1.setBounds(100,100,150,20);
cb2=new JCheckBox("Burger @ 30");
cb2.setBounds(100,150,150,20);
cb3=new JCheckBox("Tea @ 10");
cb3.setBounds(100,200,150,20);
b=new JButton("Order");
b.setBounds(100,250,80,30);
b.addActionListener(this);
add(l);add(cb1);add(cb2);add(cb3);add(b);
setSize(400,400);
setLayout(null);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public void actionPerformed(ActionEvent e){
float amount=0;
String msg="";
if(cb1.isSelected()){
amount+=100;
msg="Pizza: 100\n";
}
if(cb2.isSelected()){
amount+=30;
msg+="Burger: 30\n";
}
if(cb3.isSelected()){
amount+=10;
msg+="Tea: 10\n";
}
msg+="-----------------\n";
JOptionPane.showMessageDialog(this,msg+"Total: "+amount);
}
public static void main(String[] args) {
new CheckBoxExample();
}
}

输出：