java - 检查 JToggleButton 是否被按下并禁用它

Question

我有一个 JTogglebuttons 数组和一个 JButton，当按下 JButton 时，它会启动一个循环，迭代所有 JTogglebuttons 以查看它是否被按下，如果是，则应使其禁用/不可点击

这是有问题的代码片段

Public void actionPerformed(ActionEvent e){
        Object pressed = e.getSource(); 
        if (pressed == btnPurchase) {
            for(int row = 0; row<8 ; row++){
                for(int column = 0; column < 4; column++) {     
                    if (seat[row][column].isPressed()) {
                        seat[row][column].setEnabled(false);
                    }
                }
            }
        }

我收到此错误

cannot find symbol
symbol  : method isPressed()
location: class javax.swing.JToggleButton
                    if (seat[row][column].isPressed()) {

如果我使用.isSelected

我明白

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at cinemaManager.actionPerformed(cinemaManager.java:174)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2028)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2351)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
    at java.awt.Component.processMouseEvent(Component.java:6375)

Answer 1

寻找ButtonModel，返回预期的方法，包括isSelected

import javax.swing.ButtonModel;
import javax.swing.JFrame;
import javax.swing.JToggleButton;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class JToggleButtonChangeListener {

    public static void main(String args[]) {
        JFrame frame = new JFrame("Selecting Toggle");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        final JToggleButton toggleButton = new JToggleButton("Selecting Toggle / Deselacting Toggle");
        toggleButton.addChangeListener(new ChangeListener() {

            @Override
            public void stateChanged(ChangeEvent e) {
                ButtonModel buttonModel = toggleButton.getModel();
                boolean armed = buttonModel.isArmed();
                boolean pressed = buttonModel.isPressed();
                boolean selected = buttonModel.isSelected();
                System.out.println("Changed: " + armed + "/" + pressed + "/" + selected);
            }
        });
        frame.add(toggleButton);
        frame.pack();
        frame.setLocation(150, 150);
        frame.setVisible(true);
    }
}

通知:背景的更改不适用于所有外观和感觉