CardLayout获取所选卡的名称

Question

如何在卡布局中获取所选面板的字符串标识符.

Answer 1

CardLayout不知道当前选择的面板是什么.在调用show()方法时,你应该自己将它保存在内存中.

Answer 2

CardLayout不允许您这样做.但是,您应该能够访问CardLayout的顶部面板.

因此,稍微解决一下是为每个添加的面板命名,等于字符串标识符.这样你就可以获得顶级卡,并得到它的名字.这是你如何做到的:

final String CARD1 = "Card 1";
final String CARD2 = "Card 2";

JPanel panel = new JPanel(new CardLayout());
JPanel card1 = new JPanel();
card1.setName(CARD1);
JPanel card2 = new JPanel();
card2.setName(CARD2);

panel.add(card1);
panel.add(card2);

//now we want to get the String identifier of the top card:
JPanel card = null;
for (Component comp : panel.getComponents()) {
    if (comp.isVisible() == true) {
        card = (JPanel) comp;
    }
}
System.out.println(card.getName());