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我正在创建一个可以存款、取款、创建帐户和显示所有余额的银行。

我的 createButton 方法工作正常 -

    public void createNewAccountButtonPanel(){
    //create button
    createButton = new JButton("Create New Account");
    //Add Listener modeled from InputFrame.Java from GroupProject
    class AddCreateNewListener implements ActionListener{
        @Override
        public void actionPerformed(ActionEvent CreateNew){
            //account number has to be 4 digits. Balance has to be 100 or more
            if(accountField.getText().trim().length() != 4 || balanceField.getText().trim().length() < 3){
                //not correct input, tell the user to enter the correct input
                System.out.println("Failed to create a Bank Account!");
                textArea.append("Please enter a Account number and a Balance!" + "\n");
            }
            else
            {//read the input
                System.out.println("Creating a Bank Account!");
                Integer accountNumber = Integer.parseInt(accountField.getText());
                Double amount = Double.parseDouble(balanceField.getText());
                getBank().createNew(accountNumber, amount);
                textArea.append("You created " + getBank().accounts.get(getBank().accounts.size()-1) + "   \n");
            }
            }   
    }
    createNew = new AddCreateNewListener();
    createButton.addActionListener(createNew);  
}

这是我的搜索 - 它总是返回 null，即使我知道我已经添加了一个帐户......

    public BankAccount search(Integer accountNumber){
    BankAccount found = null;
    for(BankAccount a : accounts){
        if(a.getAccountNumber() == accountNumber) {
            System.out.println("Found the account!");
            found = a;     
        }
        else{
            System.out.println("The Account Number you entered was not found.");
            found = null;
        }
    }       
    return found;
}

我错过了什么？这也导致我的存款和取款按钮现在可以工作。我的显示所有帐户工作得很好。

编辑：看来我的搜索正在工作，我添加了一个break. 现在的问题是让平衡显示在 gui 的文本区域 - 它总是显示 0.0

    public void displayBalancePanel(){
    //create the button
    displayBalanceButton = new JButton("Display The Balance");
    //Add listener modeled from InputFrame.java from GroupProject
    class AddDisplayBalanceListener implements ActionListener{
        @Override
        public void actionPerformed(ActionEvent DisplayBalance){
            //read the input
            Integer accountNumber = Integer.parseInt(accountField.getText());
            System.out.println("accountNumber to Display Balance for: " + accountNumber);
            getBank().displayBalance(accountNumber, amount);
            textArea.append("The Balance for Account: " + accountNumber + " is " + getAmount() + "\n");
        }
    }
    displayBalance = new AddDisplayBalanceListener();
    displayBalanceButton.addActionListener(displayBalance);
}

新搜索 -

    public BankAccount search(Integer accountNumber){
    BankAccount found = null;
    for(BankAccount a : accounts){
        if(a.getAccountNumber().equals(accountNumber)) {
            System.out.println("Found the account!");
            found = a;     
            System.out.println("a: " + a);
            break;
        }
        else{
            System.out.println("The Account Number you entered was not found.");
            found = null;
        }
    }       
    return found;
}
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1 回答 1

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找到帐户后，您的for循环会不断超出所需的Account. 然后else套found回null。

找到帐户后，只需将其从if块中的那里归还即可。你甚至不需要一个else块。

事实上，你根本不需要这个变量found。a直接在block中return即可，方法中的最后一条语句如果没找到if可以改成。return null;

于 2013-07-19T18:28:16.520 回答