我如何从AccountApplet类中的Account类调用setBalance（）方法，我相信它应该放在AccountApplet类的actionPerformed方法中。
请注意，当我在actionperformed中创建新的帐户对象时，我收到此错误 AccountApplet.java:83：错误：构造函数类Account中的帐户不能应用于给定类型; 帐户帐户=新帐户（）。setBalance; ^ required：int，double 发现：没有争论 原因：实际和正式的参数列表长度不同
这是我的帐户类
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Account
{
int id = 1234;
double balance = 1000.00;
Account (int id, double balance)
{
id = 1234;
this.balance = balance;
}
public int getId()
{
return id;
}
public double getBalance()
{
return balance;
}
public void setBalance(double balance) throws NegativeAmountException
{
if ( balance < 0)
throw new NegativeAmountException();
this.balance = balance;
}
public void deposit(double amount) throws NegativeAmountException
{
if (amount < 0)
throw new NegativeAmountException();
balance += amount;
}
public void withdraw(double amount) throws NegativeAmountException,
InsufficientFundsException
{
if (amount <= balance )
{
throw new NegativeAmountException();
}
if (amount <= balance )
{
throw new InsufficientFundsException();
}
balance -= amount;
}
}
最近将进行调用的AccountApplet类，刷新字段方法中有一个帐户对象
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.border.*;
import java.text.NumberFormat;
public class AccountApplet extends JApplet implements ActionListener
{
// For West
public JLabel ai = new JLabel("Account ID ");
public JTextField aitf = new JTextField();
public JLabel ab = new JLabel("Account Balance ");
public JTextField abtf = new JTextField();
// For East
public JButton dp = new JButton ("Deposit");
public JTextField dptf = new JTextField();
public JButton wt = new JButton ("Withdraw");
public JTextField wttf = new JTextField();
// For South
public JLabel status = new JLabel("");
public void init()
{
this.setSize(400, 90);
//----------------------
// Set up the Structure
//----------------------
Container c = getContentPane();
JPanel b = new JPanel(new BorderLayout());
JPanel west = new JPanel(new GridLayout(2,2));
JPanel east = new JPanel(new BorderLayout());
JPanel depo_with = new JPanel(new GridLayout(2,2));
// Add BorderLayout to the container
c.add(b);
// Add everything to West
b.add(west, BorderLayout.WEST);
west.setBorder(new TitledBorder("Display Account Information"));
west.add(ai);
west.add(aitf);
aitf.setEditable(false);
west.add(ab);
west.add(abtf);
abtf.setEditable(false);
// Add everything to EAST
b.add(east, BorderLayout.EAST);
east.setBorder(new TitledBorder("Deposit or Withdrawl Funds"));
east.add(depo_with, BorderLayout.EAST);
depo_with.add(dptf);
depo_with.add(dp);
depo_with.add(wttf);
depo_with.add(wt);
dp.addActionListener(this);
wt.addActionListener(this);
// Add everything to SOUTH
b.add(status, BorderLayout.SOUTH);
refreshFields();
} // End intit
public void actionPerformed(ActionEvent e)
{
if (e.getSource() == dp) // Executes if deposit was clicked
{
try
{
getAmount(dptf);
status.setText("Deposit processed");
refreshFields();
}
catch (NegativeAmountException nae)
{
status.setText(nae.getMessage() + " not allowed for deposit");
}
catch (EmptyFieldException efe)
{
status.setText(efe.getMessage() + " not allowed for deposit");
}
catch (Exception ex)
{
status.setText(ex.getMessage() + " not allowed for deposit");
}
}
if (e.getSource() == wt) // Executes if withdraw was clicked
{
try
{
getAmount(wttf);
status.setText("Withdraw processed");
refreshFields();
}
// catch (InsufficientFundsException ife)
// {
// status.setText(ife.getMessage() + " Insufficient funds");
// }
catch (NegativeAmountException nae)
{
status.setText(nae.getMessage() + " not allowed for withdraw");
}
catch (EmptyFieldException efe)
{
status.setText(efe.getMessage() + " not allowed for withdraw");
}
catch (Exception ex)
{
// Something went wrong - handle your error here
status.setText(" for withdraw");
}
refreshFields();
}
}
public void refreshFields()
{
NumberFormat fmt = NumberFormat.getCurrencyInstance();
Account Account1 = new Account(1234, 1000.00);
aitf.setText("" + Account1.getId());
abtf.setText("" + fmt.format(Account1.getBalance()));
// diplays accound id and balance in left text fields
//should be called when the applet is first displayed and after each valid transaction
}
public double getAmount(JTextField tf) throws EmptyFieldException,
NumberFormatException,
NegativeAmountException
{
double depo;
try
{
depo = Double.parseDouble(dptf.getText()); // read in one textfield and convert to a number
}
catch (NumberFormatException nfe) // catch NumberFormatException
{
throw nfe; // catch throws NumberFormatException
}
return depo;
} // End
} // End Class
答案 0 :(得分：1)
如果您希望使用AccountApplet类，则需要在AccountApplet类中实例化。这将放在AccountApplet类的顶部，其中包含您已定义的其他属性
*不要忘记添加参数（我随机选择了1和20）
Account newAccount = new Account(1, 20);
您现在可以使用对象方法。例如，如果您希望存入金额，您可以执行以下操作：
public void actionPerformed(ActionEvent e)
{
if (e.getSource() == dp) // Executes if deposit was clicked{
try
{
getAmount(dptf);
newAccount.deposit(dptf)
status.setText("Deposit processed");
refreshFields();
}
代码行
newAccount.deposit(dptf)
调用Account类
的存款方式您可以在此处看到余额也会更新（请查看帐户类中的存款方式）
该行
balance += amount
更新余额（此行代码相当于余额=余额+金额）
答案 1 :(得分：0)
请创建Account类的实例，然后调用setBalance方法，像这样传入参数
public void actionPerformed(ActionEvent e)
{
Account account=new Account(1,0);//where 1 is your account id and 0 is your initail balance
//Yor call here
if (e.getSource() == dp) // Executes if deposit was clicked
{
try
{
account.setBalance(20);
getAmount(dptf);
status.setText("Deposit processed");
refreshFields();
}
catch (NegativeAmountException nae)
{
status.setText(nae.getMessage() + " not allowed for deposit");
}
catch (EmptyFieldException efe)
{
status.setText(efe.getMessage() + " not allowed for deposit");
}
catch (Exception ex)
{
status.setText(ex.getMessage() + " not allowed for deposit");
}
}