java 【jradiobutton | Java 摇摆】

【jradiobutton | Java 摇摆】

哎哎哎::1230【https://www . geeksforgeeks . org/jradiobutton-Java-swing/

我们使用 JRadioButton 类来创建一个单选按钮。单选按钮用于从多个选项中选择一个选项。它用于填写表格、在线客观试卷和测验。

我们在按钮组中添加单选按钮，这样我们一次只能选择一个单选按钮。我们使用“按钮组”类来创建一个按钮组，并在一个组中添加单选按钮。

使用的方法:

JRadioButton():创建一个没有文本的未选中的单选按钮。例:

JRadioButton j1 = new JRadioButton()

创建一个带有特定文本的按钮。示例:

```java JButton b1 = new JButton("Button")

```
- 创建一个带有特定文本的标签。示例:
```java JLabel L = new JLabel("Label 1")

```
- ButtonGroup():用于创建一个组，我们可以在其中添加 JRadioButton。我们只能在一个按钮组中选择一个按钮。 将单选按钮组合在一起的步骤。
- 使用“按钮组()”方法创建一个按钮组实例。
  
```java ButtonGroup G = new ButtonGroup()

```
- Now add buttons in a Group “G”, with the help of “add()” Method.
  
  示例:
  
```java G.add(Button1); G.add(Button2);

```
  - isSelected() : it will return a Boolean value true or false, if a JRadioButton is selected it Will return true otherwise false.
示例:

```java JRadioButton.isSelected()

```
- Set(…) and Get(…) Methods : i) Set and get are used to replace directly accessing member variables from external classes.
ii)不是直接访问类成员变量，而是定义 get 方法来访问这些变量，并设置方法来修改它们。

程序中使用的一些功能的描述，在此链接给出:功能描述

程序 1 : JRadioButton 无动作监听器

```java // Java program to show JRadioButton Example. // in java. Importing different Package. import java.awt.; import javax.swing.; import java.awt.event.*;

class Demo extends JFrame {

// Declaration of object of JRadioButton class.     JRadioButton jRadioButton1;

// Declaration of object of JRadioButton class.     JRadioButton jRadioButton2;

// Declaration of object of JButton class.     JButton jButton;

// Declaration of object of ButtonGroup class.     ButtonGroup G1;

// Declaration of object of JLabel class.     JLabel L1;

// Constructor of Demo class.     public Demo()     {

// Setting layout as null of JFrame.         this.setLayout(null);

// Initialization of object of "JRadioButton" class.         jRadioButton1 = new JRadioButton();

// Initialization of object of "JRadioButton" class.         jRadioButton2 = new JRadioButton();

// Initialization of object of "JButton" class.         jButton = new JButton("Click");

// Initialization of object of "ButtonGroup" class.         G1 = new ButtonGroup();

// Initialization of object of " JLabel" class.         L1 = new JLabel("Qualification");

// setText(...) function is used to set text of radio button.         // Setting text of "jRadioButton2".         jRadioButton1.setText("Under-Graduate");

// Setting text of "jRadioButton4".         jRadioButton2.setText("Graduate");

// Setting Bounds of "jRadioButton2".         jRadioButton1.setBounds(120, 30, 120, 50);

// Setting Bounds of "jRadioButton4".         jRadioButton2.setBounds(250, 30, 80, 50);

// Setting Bounds of "jButton".         jButton.setBounds(125, 90, 80, 30);

// Setting Bounds of JLabel "L2".         L1.setBounds(20, 30, 150, 50);

// "this" keyword in java refers to current object.         // Adding "jRadioButton2" on JFrame.         this.add(jRadioButton1);

// Adding "jRadioButton4" on JFrame.         this.add(jRadioButton2);

// Adding "jButton" on JFrame.         this.add(jButton);

// Adding JLabel "L2" on JFrame.         this.add(L1);

// Adding "jRadioButton1" and "jRadioButton3" in a Button Group "G2".         G1.add(jRadioButton1);         G1.add(jRadioButton2);     } }

class RadioButton {     // Driver code.     public static void main(String args[])     { // Creating object of demo class.         Demo f = new Demo();

// Setting Bounds of JFrame.         f.setBounds(100, 100, 400, 200);

// Setting Title of frame.         f.setTitle("RadioButtons");

// Setting Visible status of frame as true.         f.setVisible(true);     } } ```

输出:

程序 2:带动作监听器的 JRadioButton】

```java // Java program to show JRadioButton Example. // in java. Importing different Package. import java.awt.; import javax.swing.; import java.awt.event.*;

class Demo extends JFrame {

// Declaration of object of JRadioButton class.     JRadioButton jRadioButton1;

// Declaration of object of JRadioButton class.     JRadioButton jRadioButton2;

// Declaration of object of JButton class.     JButton jButton;

// Declaration of object of ButtonGroup class.     ButtonGroup G1;

// Declaration of object of JLabel class.     JLabel L1;

// Constructor of Demo class.     public Demo()     {

// Setting layout as null of JFrame.         this.setLayout(null);

// Initialization of object of "JRadioButton" class.         jRadioButton1 = new JRadioButton();

// Initialization of object of "JRadioButton" class.         jRadioButton2 = new JRadioButton();

// Initialization of object of "JButton" class.         jButton = new JButton("Click");

// Initialization of object of "ButtonGroup" class.         G1 = new ButtonGroup();

// Initialization of object of " JLabel" class.         L1 = new JLabel("Qualification");

// setText(...) function is used to set text of radio button.         // Setting text of "jRadioButton2".         jRadioButton1.setText("Under-Graduate");

// Setting text of "jRadioButton4".         jRadioButton2.setText("Graduate");

// Setting Bounds of "jRadioButton2".         jRadioButton1.setBounds(120, 30, 120, 50);

// Setting Bounds of "jRadioButton4".         jRadioButton2.setBounds(250, 30, 80, 50);

// Setting Bounds of "jButton".         jButton.setBounds(125, 90, 80, 30);

// Setting Bounds of JLabel "L2".         L1.setBounds(20, 30, 150, 50);

// "this" keyword in java refers to current object.         // Adding "jRadioButton2" on JFrame.         this.add(jRadioButton1);

// Adding "jRadioButton4" on JFrame.         this.add(jRadioButton2);

// Adding "jButton" on JFrame.         this.add(jButton);

// Adding JLabel "L2" on JFrame.         this.add(L1);

// Adding "jRadioButton1" and "jRadioButton3" in a Button Group "G2".         G1.add(jRadioButton1);         G1.add(jRadioButton2);

// Adding Listener to JButton.         jButton.addActionListener(new ActionListener() {             // Anonymous class.

public void actionPerformed(ActionEvent e)             {                 // Override Method

// Declaration of String class Objects.                 String qual = " ";

// If condition to check if jRadioButton2 is selected.                 if (jRadioButton1.isSelected()) {

qual = "Under-Graduate";                 }

else if (jRadioButton2.isSelected()) {

qual = "Graduate";                 }                 else {

qual = "NO Button selected";                 }

// MessageDialog to show information selected radion buttons.                 JOptionPane.showMessageDialog(Demo.this, qual);             }         });     } }

class RadioButton {     // Driver code.     public static void main(String args[])     { // Creating object of demo class.         Demo f = new Demo();

// Setting Bounds of JFrame.         f.setBounds(100, 100, 400, 200);

// Setting Title of frame.         f.setTitle("RadioButtons");

// Setting Visible status of frame as true.         f.setVisible(true);     } } ```

输出:

按下按钮“点击”后。

程序 3 程序创建一组简单的单选按钮(带图像)并在其中添加项目监听器

```java // Java Program to create a simple group of radio buttons // (with image )and add item listener to them import java.awt.event.; import java.awt.; import javax.swing.*; class solve extends JFrame implements ItemListener {

// frame     static JFrame f;

// radiobuttons     static JRadioButton b, b1;

// create a label     static JLabel l1;

// main class     public static void main(String[] args)     {         // create a new frame         f = new JFrame("frame");

// create a object         solve s = new solve();

// create a panel         JPanel p = new JPanel();

// create a new label         JLabel l = new JLabel("which website do you like?");         l1 = new JLabel("geeksforgeeks selected");

// create Radio buttons         b = new JRadioButton("geeksforgeeks", new ImageIcon("f:/gfg.jpg"));         b1 = new JRadioButton("others");

// create a button group         ButtonGroup bg = new ButtonGroup();

// add item listener         b.addItemListener(s);         b1.addItemListener(s);

// add radio buttons to button group         bg.add(b);         bg.add(b1);

b.setSelected(true);

// add button and label to panel         p.add(l);         p.add(b);         p.add(b1);         p.add(l1);

f.add(p);

// set the size of frame         f.setSize(400, 400);

f.show();     }

public void itemStateChanged(ItemEvent e)     {         if (e.getSource() == b) {             if (e.getStateChange() == 1) {                 l1.setText("geeksforgeeks selected");             }         }         else {

if (e.getStateChange() == 1) {                 l1.setText("others selected");             }         }     } } ```

输出:

注意:以下程序可能无法在联机编译器中运行，请使用脱机 IDE。