我有一个Calculator类，它将从4个文本域中的3个中获取输入，然后使用我已经制作的Loan类计算另一个。
现在我需要添加“计算器样式”按钮，用户可以使用这些按钮将这些ammounts输入到TextFields中。这是我到目前为止所拥有的。 。 。
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Vector;
public class Calculator extends JFrame implements ActionListener
{
public static final int width = 400;
public static final int height = 300;
private JButton calculate;
private static JTextField amount;
private JTextField interest;
private JTextField term;
private JTextField payment;
private JLabel amountL;
private JLabel interestL;
private JLabel termL;
private JLabel paymentL;
private String i = "0";
public Calculator ()
{
super("Loan Calculator");
setSize(width, height);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
calculate = new JButton("payment");
calculate.setFocusable(false);
amount = new JTextField(10);
interest = new JTextField(10);
term = new JTextField(10);
payment = new JTextField(10);
JPanel numbButt = new JPanel();
numbButt.setLayout(new GridLayout(4,3));
JButton zero = new JButton("0");
zero.setFocusable(false);
JButton one = new JButton("1");
one.setFocusable(false);
JButton two = new JButton("2");
two.setFocusable(false);
JButton three = new JButton("3");
three.setFocusable(false);
JButton four = new JButton("4");
four.setFocusable(false);
JButton five = new JButton("5");
five.setFocusable(false);
JButton six = new JButton("6");
six.setFocusable(false);
JButton seven = new JButton("7");
seven.setFocusable(false);
JButton eight = new JButton("8");
eight.setFocusable(false);
JButton nine = new JButton("9");
nine.setFocusable(false);
JButton period = new JButton(".");
period.setFocusable(false);
numbButt.add(seven);
seven.addActionListener(this);
numbButt.add(eight);
eight.addActionListener(this);
numbButt.add(nine);
nine. addActionListener(this);
numbButt.add(four);
four.addActionListener(this);
numbButt.add(five);
five.addActionListener(this);
numbButt.add(six);
six.addActionListener(this);
numbButt.add(one);
one.addActionListener(this);
numbButt.add(two);
two.addActionListener(this);
numbButt.add(three);
three.addActionListener(this);
numbButt.add(zero);
zero.addActionListener(this);
numbButt.add(period);
period.addActionListener(this);
JButton enter = new JButton("enter");
enter.setFocusable(false);
numbButt.add(enter);
enter.addActionListener(this);
JPanel inputPanel = new JPanel();
inputPanel.setLayout(new GridLayout(4,2));
setLayout(new BorderLayout());
amountL = new JLabel("amount");
interestL = new JLabel("interest");
termL = new JLabel("term");
paymentL = new JLabel("payment");
inputPanel.add(amountL);
inputPanel.add(amount);
inputPanel.add(interestL);
inputPanel.add(interest);
inputPanel.add(termL);
inputPanel.add(term);
inputPanel.add(paymentL);
inputPanel.add(payment);
add(inputPanel, BorderLayout.CENTER);
calculate.addActionListener(this);
JButton amountB = new JButton("amount");
amountB.setFocusable(false);
amountB.addActionListener(this);
JPanel buttonPanel = new JPanel();
buttonPanel.add(calculate);
buttonPanel.add(amountB);
add(buttonPanel, BorderLayout.SOUTH);
add(numbButt, BorderLayout.WEST);
interest.requestFocusInWindow();
ActionListener actionListener = new ActionFocusMover();
enter.addActionListener(actionListener);
}
@Override
public void actionPerformed(ActionEvent e)
{
String iamt, ii, iterm, ipmt;
String buttonString = e.getActionCommand();
Component x;
if(buttonString.equals("1"))
i=i+1;
else if(buttonString.equals("2"))
i=i+2;
else if(buttonString.equals("3"))
i=i+3;
else if(buttonString.equals("4"))
i=i+4;
else if(buttonString.equals("5"))
i=i+5;
else if(buttonString.equals("6"))
i=i+6;
else if(buttonString.equals("7"))
i=i+7;
else if(buttonString.equals("8"))
i=i+8;
else if(buttonString.equals("9"))
i=i+9;
else if(buttonString.equals("0"))
i=i+0;
else if(buttonString.equals("."))
i=i+".";
else if(buttonString.equals("enter"))
else if(buttonString.equals("payment"))
{
iamt = amount.getText();
ii = interest.getText();
iterm = term.getText();
Loan justin = new Loan(Integer.parseInt(iterm),Double.parseDouble(ii), Double.parseDouble(iamt));
payment.setText(Double.toString(justin.getPayment()));
}
else
{
ii = interest.getText();
iterm = term.getText();
ipmt = payment.getText();
Loan justin = new Loan(Double.parseDouble(ipmt), Integer.parseInt(iterm),Double.parseDouble(ii));
amount.setText(Double.toString(justin.getAmount()));
}
amount.setText(i);
}
public static void setFocus()
{
amount.requestFocusInWindow();
}
class ActionFocusMover implements ActionListener {
public void actionPerformed(ActionEvent actionEvent) {
KeyboardFocusManager manager = KeyboardFocusManager.getCurrentKeyboardFocusManager();
manager.focusNextComponent();
}
}
}
我设置的方式允许将按钮输入字符串，然后暂时放入静态字段（金额）。我需要知道的是如何编辑来检查哪个对象当前具有焦点，并将inputbuttonString放入该对象中。 编辑
答案 0 :(得分：1)
您可以使用requestFocusInWindow方法设置对组件的关注。确保组件可显示，可聚焦且可见。
来自How to Use the Focus Subsystem
如果您想确保特定组件获得焦点 第一次激活一个窗口，你可以调用 组件之后的组件上的requestFocusInWindow方法 已经实现，但在显示框架之前。
要在Amount之后设置requestFocusInWindow字段调用pack()的初始焦点。
相同的教程提供了有关focus traversal policy和focus traversal keys的示例。例如，如何将Enter添加为焦点遍历键：
Set forwardKeys = getFocusTraversalKeys(
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS);
Set newForwardKeys = new HashSet(forwardKeys);
newForwardKeys.add(KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0));
setFocusTraversalKeys(KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS,
newForwardKeys);
或者，您可以将焦点转移到JTextArea动作方法中，该方法会对Enter击键作出反应，即：
amount.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
interest.requestFocusInWindow();
}
});