java - 我无法将组合框的值传递到对象中。错误是 'incompatible types:Object cannot be converted to size'

Question

我的项目中有一堆枚举，我已将它们用于组合框中的值，但是当我将这些值传递到我的“披萨”类时，它给了我错误。

public class Pizza {
    private Size size;
    private Crust crust;
    private Sauce sauce;
    private Topping topping1;
    private Topping topping2;
    public Pizza(Size size,Crust crust, Sauce sauce,
                 Topping topping1,Topping topping2){
        this.size=size;
        this.crust=crust;
        this.sauce=sauce;
        this.topping1=topping1;
        this.topping2=topping2;
    }
    //blah blah
------------------------------------------
//This is one of my enums.
public enum Size {
    SMALL(9.45),MEDIUM(11.87),LARGE(15.9);
    private double size;
Size(double size){this.size=size;}
public double getSize(){return this.size;}
public String getSizeAsString(){return String.valueOf(size);}

}
-------------------------------------------
public class PizzaForm extends javax.swing.JFrame {

    public PizzaForm() {
        initComponents();
        initiateComboBoxes();

    }
public void initiateComboBoxes(){
    cboSize.setModel(new DefaultComboBoxModel<>(Size.values()));
}
---------------------------------------------
private void btnAddToOrderActionPerformed(java.awt.event.ActionEvent evt) {                                              
        //when button clicked..
        Pizza pizza=new Pizza(cboSize.getSelectedItem(),cboCrust.getSelectedItem(),cboSauce.getSelectedItem(),cboTopping1.getSelectedItem(),cboTopping2.getSelectedItem());
    }

错误出现在倒数第二行。它突出显示了我的整个错误行。谁能告诉我可能是什么问题？我没有将任何内容转换为“大小”，所以我不知道问题是什么。谢谢

Answer 1

JComboBox#getSelectedItem() 不是“泛型化”的，因此只知道返回原始对象类型。您需要将从该方法返回的对象转换为适当的类型，例如本例中的 Size。

所以:

Pizza pizza = new Pizza((Size) cboSize.getSelectedItem(), 
                        (Crust) cboCrust.getSelectedItem(), 
                        (Sauce) cboSauce.getSelectedItem(), 
                        (Topping) cboTopping1.getSelectedItem(), 
                        (Topping) cboTopping2.getSelectedItem());