据我所知，showinputdialog 返回一个字符串类型的 output 但它给了我一个错误，它无法将 object 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：

不兼容的类型：Object 无法转换为字符串

Answer 1

有了这么多参数， showInputDialog方法不返回字符串，而是返回 Object，如javadoc中所述

正如Swing 教程中所建议的，您只需将结果转换为字符串。

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