【從零開始學 Java 程式設計】JRadioButton 元件
【從零開始學 Java 程式設計】 線上教學課程目錄，使用 Java 程式語言，開發應用程式。
JRadioButton
JRadioButton 單選按鈕元件，可以提供很多選項，讓使用者單選
範例
學習如何使用 ButtonGroup 將三個 JRadioButton 變成一個單選群組，當使用者點選其中一個 JRadioButton 選項，下方 JLabel 元件，顯示剛選擇的項目名稱
關鍵程式碼
private JLabel jLabel;
public void addComponentsToPane(Container pane) {
pane.setLayout(new BorderLayout());
Box box = new Box(BoxLayout.Y_AXIS);
ButtonGroup buttonGroup = new ButtonGroup();
JRadioButton rbSpider = new JRadioButton("蜘蛛");
rbSpider.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
updateChoice(rbSpider.getText());
}
});
rbSpider.setAlignmentX(Component.CENTER_ALIGNMENT);
buttonGroup.add(rbSpider);
box.add(rbSpider);
JRadioButton rbCockroach = new JRadioButton("蟑螂");
rbCockroach.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
updateChoice(rbCockroach.getText());
}
});
rbCockroach.setAlignmentX(Component.CENTER_ALIGNMENT);
buttonGroup.add(rbCockroach);
box.add(rbCockroach);
JRadioButton rbfly = new JRadioButton("蒼蠅");
rbfly.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
updateChoice(rbfly.getText());
}
});
rbfly.setAlignmentX(Component.CENTER_ALIGNMENT);
buttonGroup.add(rbfly);
box.add(rbfly);
jLabel = new JLabel("請選擇...");
jLabel.setAlignmentX(Component.CENTER_ALIGNMENT);
jLabel.setBorder(BorderFactory.createEmptyBorder(30, 0, 0, 0));
box.add(jLabel);
box.setBorder(BorderFactory.createEmptyBorder(30, 0, 0, 0));
pane.add(box, BorderLayout.CENTER);
}
private void updateChoice(String text) {
jLabel.setText("你選擇了： " + text);
}
完整程式碼
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class DemoJRadioButton {
private JLabel jLabel;
public void addComponentsToPane(Container pane) {
pane.setLayout(new BorderLayout());
Box box = new Box(BoxLayout.Y_AXIS);
ButtonGroup buttonGroup = new ButtonGroup();
JRadioButton rbSpider = new JRadioButton("蜘蛛");
rbSpider.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
updateChoice(rbSpider.getText());
}
});
rbSpider.setAlignmentX(Component.CENTER_ALIGNMENT);
buttonGroup.add(rbSpider);
box.add(rbSpider);
JRadioButton rbCockroach = new JRadioButton("蟑螂");
rbCockroach.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
updateChoice(rbCockroach.getText());
}
});
rbCockroach.setAlignmentX(Component.CENTER_ALIGNMENT);
buttonGroup.add(rbCockroach);
box.add(rbCockroach);
JRadioButton rbfly = new JRadioButton("蒼蠅");
rbfly.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
updateChoice(rbfly.getText());
}
});
rbfly.setAlignmentX(Component.CENTER_ALIGNMENT);
buttonGroup.add(rbfly);
box.add(rbfly);
jLabel = new JLabel("請選擇...");
jLabel.setAlignmentX(Component.CENTER_ALIGNMENT);
jLabel.setBorder(BorderFactory.createEmptyBorder(30, 0, 0, 0));
box.add(jLabel);
box.setBorder(BorderFactory.createEmptyBorder(30, 0, 0, 0));
pane.add(box, BorderLayout.CENTER);
}
private void updateChoice(String text) {
jLabel.setText("你選擇了： " + text);
}
public DemoJRadioButton() {
JFrame frame = new JFrame("HKT線上教室");
// 獲取螢幕解析度
Dimension dimension = Toolkit.getDefaultToolkit().getScreenSize();
frame.setSize(dimension.width / 4, dimension.height / 4);
//設定視窗顯示在螢幕畫面中間位置
int x = (int) ((dimension.getWidth() - frame.getWidth()) / 2);
int y = (int) ((dimension.getHeight() - frame.getHeight()) / 2);
frame.setLocation(x, y);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//設定關閉可以關掉程式
//在 Pane 畫面中加入元件
addComponentsToPane(frame.getContentPane());
// frame.pack();
frame.setVisible(true);
}
//最一開始程式進入點
public static void main(String[] args) {
//使用 invokeLater 確保 UI 在排程執行緒內
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
new DemoJRadioButton();
}
});
}
}
參考資料
那這次的課程就介紹到這邊囉～
順帶一提，KT 線上教室，臉書粉絲團，會不定期發佈相關資訊，不想錯過最新資訊，不要忘記來按讚，加追蹤喔！也歡迎大家將這套課程分享給更多人喔。
我們下次再見囉！！！掰掰～
