Question

如何编写代码以从JTextField获取文本并将其转换为双精度字符？

我用amountField创建了一个银行帐户类和一个银行帐户GUI，以显示我希望提取和存入的金额。如何使用public void actionPerformed(ActionEvent e)方法编写代码以从amountField获取文本并将其转换为double？

我想输入帐户详细信息，并能够在将值存储在字符串中的同时提款和存款

为存款按钮编写事件处理程序
为退出按钮编写事件处理程序

public class BankAccountGUI extends JFrame implements ActionListener
{
    private Label amountLabel = new Label("Amount");
    private JTextField amountField = new JTextField(5);
    private JButton depositButton = new JButton("DEPOSIT");
    private JButton withdrawButton = new JButton("WITHDRAW");
    private Label balanceLabel = new Label("Starting Balance = 0" );

    private JPanel topPanel = new JPanel();
    private JPanel bottomPanel = new JPanel();
    private JPanel middlePanel = new JPanel();


    BankAccount myAccount = new BankAccount("James","12345");

    // declare a new BankAccount object (myAccount) with account number and name of your choice here


    public BankAccountGUI()
    {
        setTitle("BankAccount GUI");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        setSize(340, 145);
        setLocation(300,300);
        depositButton.addActionListener(this);
        withdrawButton.addActionListener(this);

        topPanel.add(amountLabel);
        topPanel.add(amountField);
        bottomPanel.add(balanceLabel);
        middlePanel.add(depositButton);
        middlePanel.add(withdrawButton);


        add (BorderLayout.NORTH, topPanel);
        add(BorderLayout.SOUTH, bottomPanel);
        add(BorderLayout.CENTER, middlePanel);

        setVisible(true);
    }


    public void actionPerformed(ActionEvent e)
    {
         //What goes here?
    }
}

Answer 1

您可能要尝试使用Double.parseDouble（string）。例如：

List<SearchItem> searchResults = new ArrayList<>(serverResults);
keyboardInstance.get().mAdapter.updateResults(searchResults);
keyboardInstance.get().resultListView.setAdapter(keyboardInstance.get().mAdapter);

Answer 2

这里有很多事情您需要做不同的事情。简而言之，您正在寻找“ JTextField.getText（）”和“ Double.parseDouble（）”

depositButton.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        //Get the Text Value out of the UI Component
        String rawAmount=amountField.getText();

        //Convert that value to Double
        try{
            Double convertedValue = Double.parseDouble(rawAmount);
            //Do stuff with the convertedValue
        }catch(Exception e){
            System.out.println("Not A Double Value");
        }
    }
});

对于每个按钮，还应该使用单独的侦听器，以免您尝试以编程方式确定哪个按钮生成了事件。

请参阅JTextField的文档

从JTextField获取文本并将其转换为double

2 个答案: