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"},
            "");

Error:

incompatible types: Object cannot be converted to String

Answer 1

With that much parameters, the method showInputDialog doesn't return a String but an Object as stated in the javadoc

As suggested in the Swing tutorial , you simply have to cast the result to String.

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