如何阻止cardlayout .next（）和.previous（）循环

“如果用户是在面板的开始或面板的末尾，有没有办法喜欢禁用按钮？”

根据如何使用CardLayout和CardLayout
API
，没有直接的方法可以做到这一点。

但是您可以轻松实现此功能，使int变量与当前卡号保持一致，并再次检查其值ts 0（对于第一张卡）或容器的组件数（对于最后一张卡）。例如：

public class GridBagLayoutDemo { // note pre convention!    int currentCard = 0;    Action backAction, nextAction;    ...    public GridBagLayoutDemo() {        ...        backAction = new AbstractAction("< Back") { @Override public void actionPerformed(ActionEvent e) {     currentCard--;     GridBagLayoutDemo.this.evaluateActions(); }        };        nextAction = new AbstractAction("Next >") { @Override public void actionPerformed(ActionEvent e) {     currentCard++;     GridBagLayoutDemo.this.evaluateActions(); }        };        JButton btnBack = new JButton(backAction);        ...        JButton btnNext = new JButton(nextAction);        ...    }    private void evaluateActions() {        backAction.setEnabled(currentCard > 0);        nextAction.setEnabled(currentCard < container.getComponentCount() - 1);    }    ...}

附录

仔细研究

CardLayout

public class CardLayout implements LayoutManager2,  Serializable {        Vector vector = new Vector();        int currentCard = 0;    ...        public boolean isDisplayingFirstCard() {        return currentCard == 0;    }    public boolean isDisplayingLastCard() {        return currentCard == vector.size() - 1;    }}

不知道为什么他们没有提供这种有用的功能。