java - 不同的层次结构

Question

下面的代码中指出了错误行。我注意到，如果我突出显示“客户”一词并按住 ctrl-T，它会调出显示“客户 - SwimCalc”的层次结构，这是正确的。但如果我对承包商做同样的事情，它会说承包商 - SwimCalc.Customer

public class SwimCalc extends JFrame implements ActionListener { 
    private JTabbedPane jtabbedPane;  
    private JPanel Customers; 
    private JPanel Contractors;  
    private List<Customer> customers = new ArrayList<Customer>(); 

    // this fails 
    private List<Contractor> contractors = new ArrayList<Contractor>(); 

    JTextArea NameTextCustomers, ExistTextCustomers, MessageTextCustomers,  
    NameTextContractors, ExistTextContractors, MessageTextContractors; 
    JTextField lengthTextPool, widthTextPool, depthTextPool, volumeTextPool;  

    public SwimCalc() {  
        setTitle("Volume Calculator");  
        setSize (300, 200);  

        JPanel topPanel = new JPanel();  
        topPanel.setLayout( new BorderLayout() );  
        getContentPane().add( topPanel );  

        createCustomers();  
        createContractors();  

        jtabbedPane = new JTabbedPane();  
        jtabbedPane.addTab("Customer", Customers);  
        topPanel.add(jtabbedPane, BorderLayout.CENTER);  
    } 
}

Answer 1

错误“承包商无法解析为类型”可能意味着

• 您从未在代码中的任何位置编写过 class Contractor {...}
• 由于某些构建路径问题，Eclipse 无法编译整个项目(检查“问题” View 中的构建路径错误)
• 您忘记导入类型Contractor