java - 自定义 JOptionPane 图标

Question

Java 的 "How to Make Dialogs"教程显示此代码:

//custom title, custom icon
JOptionPane.showMessageDialog(frame, "Eggs are not supposed to be green.",
        "Inane custom dialog", JOptionPane.INFORMATION_MESSAGE, icon);

这将创建以下对话框:

当图标将更改为 icon 参数时，为什么需要 JOptionPane.INFORMATION_MESSAGE？

Answer 1

该标志还指示在窗口装饰上使用哪种消息样式，请参阅 http://nadeausoftware.com/node/91#Usinglookandfeelspecificwindowdecorations

来自 JOptionPane 类源代码:

private static int styleFromMessageType(int messageType) {
    switch (messageType) {
    case ERROR_MESSAGE:
        return JRootPane.ERROR_DIALOG;
    case QUESTION_MESSAGE:
        return JRootPane.QUESTION_DIALOG;
    case WARNING_MESSAGE:
        return JRootPane.WARNING_DIALOG;
    case INFORMATION_MESSAGE:
        return JRootPane.INFORMATION_DIALOG;
    case PLAIN_MESSAGE:
    default:
        return JRootPane.PLAIN_DIALOG;
    }
}

并且在 showMessageDialog 调用的方法 showOptionDialog 中...

int style = styleFromMessageType(messageType);
JDialog dialog = pane.createDialog(parentComponent, title, style);