如何在 Java 中顯示 JRadioButtonMenuItem?\n
JRadioButtonMenuItem 是 Java 中JMenuItem類的子類。JRadioButtonMenuItem 是選單項,它是選單項組的一部分,其中組中的只能一個專案被選中,並且選中項顯示其選中狀態。我們可以將多個單選按鈕選單項新增到ButtonGroup 物件以形成一個按鈕組。如果按鈕組中的一個單選按鈕選單項被選中,所有其他單選按鈕選單項將被取消選中。
語法
public class JRadioButtonMenuItem extends JMenuItem implements Accessible
舉例
import javax.swing.*; import java.awt.*; public class JRadioButtonMenuItemTest extends JFrame { private JMenuBar mb; private JMenu m; private JRadioButtonMenuItem m1, m2, m3, m4; private ButtonGroup bg; public JRadioButtonMenuItemTest() { setTitle("JRadioButtonMenuItem Test"); setLayout(new FlowLayout()); bg = new ButtonGroup(); mb = new JMenuBar(); m = new JMenu("Menu"); m1 = new JRadioButtonMenuItem(); m2 = new JRadioButtonMenuItem(new javax.swing.text.DefaultEditorKit.BeepAction()); m3 = new JRadioButtonMenuItem("Item 3"); m4 = new JRadioButtonMenuItem("Item 4",true); m1.setText("Item 1"); m1.setFont(new Font("Tahoma",Font.PLAIN,11)); m1.setSelected(true); m2.setAccelerator(KeyStroke.getKeyStroke("ctrl 2")); m3.setEnabled(false); bg.add(m1); bg.add(m2); bg.add(m3); bg.add(m4); m.add(m1); m.add(m2); m.add(m3); m.add(m4); mb.add(m); setJMenuBar(mb); setSize(400, 300); setDefaultCloseOperation(EXIT_ON_CLOSE); setLocationRelativeTo(null); setVisible(true); } public static void main(String args[]) { new JRadioButtonMenuItemTest(); } }
輸出
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