java - 据我所知， showinputdialog 返回字符串类型的输出，但它给了我一个错误，它无法将对象转换为字符串

Question

 String val = JOptionPane.showInputDialog(null,
            "Search item to Edit ",
            "Warning",
            JOptionPane.QUESTION_MESSAGE,
            null,
            new String[]{"Item name", "Item no.","Price"},
            "");

错误:

incompatible types: Object cannot be converted to String

Answer 1

有了这么多参数，showInputDialog 方法不会返回字符串，而是返回一个对象，如 javadoc 中所述。

按照 Swing tutorial 中的建议，您只需将结果转换为 String 即可。

String val = (String) JOptionPane.showInputDialog(null,
        "Search item to Edit ",
        "Warning",
        JOptionPane.QUESTION_MESSAGE,
        null,
        new String[]{"Item name", "Item no.","Price"},
        "");