当我试图获得JFormattedTextField的大小时,我遇到了问题。实际上我需要用户输入一个简单的pinCode,然后在它之后获得他输入的内容的大小。如果他输入4位数就可以了,否则他必须再做一次。但是当我运行我的项目时,我有一个无限循环," Pin必须是4位" ...
我已经找到了这个link,但它并没有解决我的问题。
这是我的代码:
package codePin;
import java.io.*;
import java.text.NumberFormat;
import java.util.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Main extends JFrame {
private static final long serialVersionUID = 1L;
private JPanel container = new JPanel();
private JFormattedTextField jtf = new JFormattedTextField(NumberFormat.getIntegerInstance());
private JLabel label = new JLabel("Enter Pin: ");
private JButton b = new JButton("OK");
public Main() {
this.setTitle("APP");
this.setSize(300, 500);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
container.setBackground(Color.white);
container.setLayout(new BorderLayout());
JPanel top = new JPanel();
Font police = new Font("Arial", Font.BOLD, 14);
jtf.setFont(police);
jtf.setPreferredSize(new Dimension(150, 30));
jtf.setForeground(Color.BLUE);
b.addActionListener(new BoutonListener());
top.add(label);
top.add(jtf);
top.add(b);
this.setContentPane(top);
this.setVisible(true);
}
class BoutonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
int nbTry = 0;
boolean authenticated = false;
do {
do {
if (jtf.getText().length() != 4) {
System.out.println("Pin must be 4 digits");
} else {
System.out.println("Checking...");
}
ArrayList<Integer> pins = new ArrayList<Integer>();
readPinsData(new File("bdd.txt"), pins);
String[] thePins = new String[pins.size()];
for (int i = 0; i < thePins.length; i++) {
thePins[i] = pins.get(i).toString();
}
String passEntered = String.valueOf(jtf);
for (int i = 0; i < thePins.length; i++) {
if (passEntered.equals(thePins[i]) && jtf.getText().length() == 4) {
System.out.println(":)");
authenticated = true;
break;
}
}
} while (jtf.getText().length() != 4);
if (!authenticated && jtf.getText().length() == 4) {
System.out.println(":(");
nbTry++;
}
} while (nbTry < 3 && !authenticated);
//System.out.println("TEXT : jtf " + jtf.getText());
}
}
// Function to read/access my pins database (file bdd.txt)
static public boolean readPinsData(File dataFile, ArrayList<Integer> data) {
boolean err = false;
try {
Scanner scanner = new Scanner(dataFile);
String line;
while (scanner.hasNext()) {
line = scanner.nextLine();
try {
data.add(Integer.parseInt(line));
} catch (NumberFormatException e) {
e.printStackTrace();
err = true;
}
}
scanner.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
err = true;
}
return err;
}
public static void main(String[] args) {
Main fen = new Main();
}
}
bdd.txt:
1111
1234
2222
3333
4444
5555
6666
7777
8888
9999
我该怎么做?有什么想法吗?
谢谢,弗洛伦特。
答案 0 :(得分:1)
您似乎误解了actionListener的概念:Listener会侦听您的答案,而不会执行任何其他操作。您在侦听器中有等待正确数字位数的循环 - 这是错误的,您只需要在侦听器中处理一个输入(并且在另一次单击之后,将再次调用侦听器)。所以,当然,因为你的循环只有一个用户输入的答案,你得到一个非结束循环。只需在动作监听器中处理一个输入,你就可以了。以下是如何编写它的说明:http://docs.oracle.com/javase/tutorial/uiswing/events/actionlistener.html。
答案 1 :(得分:1)
所有答案都没有实际效果。简短的回答,你必须做以下检查:
if (jtf.getText().replaceAll("\u00A0","").length() != 4) {
System.out.println("Pin must be 4 digits");
JOptionPane.showMessageDialog(null,"Pin must be 4 digits");
return;
}
说明:\u0160
中使用的unicode字符NumberFormat
不是不间断的空格。在\u
之后,必须有角色的十六进制表示,即\u00A0
。
完整代码:
package codePin;
import java.io.*;
import java.text.NumberFormat;
import java.util.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.concurrent.atomic.AtomicInteger;
public class Main extends JFrame {
private static final long serialVersionUID = 1L;
private JPanel container = new JPanel();
private JFormattedTextField jtf = new JFormattedTextField(NumberFormat.getIntegerInstance());
private JLabel label = new JLabel("Enter Pin: ");
private JButton b = new JButton("OK");
public Main() {
this.setTitle("APP");
this.setSize(300, 500);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
container.setBackground(Color.white);
container.setLayout(new BorderLayout());
JPanel top = new JPanel();
Font police = new Font("Arial", Font.BOLD, 14);
jtf.setFont(police);
jtf.setPreferredSize(new Dimension(150, 30));
jtf.setForeground(Color.BLUE);
b.addActionListener(new BoutonListener());
top.add(label);
top.add(jtf);
top.add(b);
this.setContentPane(top);
this.setVisible(true);
}
class BoutonListener implements ActionListener {
private final AtomicInteger nbTry = new AtomicInteger(0);
ArrayList<Integer> pins = readPinsData("bdd.txt");
public void actionPerformed(ActionEvent e) {
if (nbTry.get() > 2) {
JOptionPane.showMessageDialog(null, "Number of tries exceeded");
return;
}
final String passEntered=jtf.getText().replaceAll("\u00A0", "");
if (passEntered.length() != 4) {
System.out.println("Pin must be 4 digits");
JOptionPane.showMessageDialog(null, "Ping must be 4 digits");
return;
}
System.out.println("Checking...");
SwingWorker worker = new SwingWorker<Void, Void>() {
@Override
protected Void doInBackground() throws Exception {
boolean authenticated = false;
if (pins.contains(Integer.parseInt(passEntered))) {
System.out.println(":)");
authenticated = true;
}
if (!authenticated) {
System.out.println(":(");
nbTry.incrementAndGet();
}
return null;
}
};
worker.execute();
}
}
// Function to read/access my pins database (file bdd.txt)
static public ArrayList<Integer> readPinsData(String dataFile) {
final ArrayList<Integer> data=new ArrayList<Integer>();
try {
BufferedReader reader = new BufferedReader(new FileReader(new File(dataFile)));
String line;
try {
while ((line = reader.readLine()) != null) {
try {
data.add(Integer.parseInt(line));
} catch (NumberFormatException e) {
e.printStackTrace();
System.err.printf("error parsing line '%s'\n", line);
}
}
} finally {
reader.close();
}
} catch (Exception e) {
e.printStackTrace();
System.err.println("error:"+e.getMessage());
}
return data;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
Main fen = new Main();
}
});
}
}
答案 2 :(得分:0)
您可以通过以下方式获取JFormattedTextField
的文本长度,例如jtf:
jtf.getText().length();
注意:根据您的意愿使用:
String s = jtf.getText();
s = s.replaceAll(",", "");
if (s.length() != 4)
但是你遇到的问题是由于你使用循环的方式。
我认为你想在用户完全输入数字时显示反应,如果是,你根本不需要循环。
根据评论:
int nbTry = 0;
定义为类成员,并在动作监听器中跟踪它。BoutonListener
里面检查一切是否正确无论如何nTry ++,如果nTry&gt; = 3做任何你想做的事。import java.io.*;
import java.text.NumberFormat;
import java.util.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Main extends JFrame {
//-------------------------------here
int nbTry = 0;
//-------------------------------here
private static final long serialVersionUID = 1L;
private JPanel container = new JPanel();
private JFormattedTextField jtf = new JFormattedTextField(NumberFormat.getIntegerInstance());
private JLabel label = new JLabel("Enter Pin: ");
private JButton b = new JButton("OK");
public Main() {
jtf.getText().length();
this.setTitle("APP");
this.setSize(300, 500);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
container.setBackground(Color.white);
container.setLayout(new BorderLayout());
JPanel top = new JPanel();
Font police = new Font("Arial", Font.BOLD, 14);
jtf.setFont(police);
jtf.setPreferredSize(new Dimension(150, 30));
jtf.setForeground(Color.BLUE);
b.addActionListener(new BoutonListener());
top.add(label);
top.add(jtf);
top.add(b);
this.setContentPane(top);
this.setVisible(true);
}
class BoutonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
String s = jtf.getText();
s = s.replaceAll(",", "");
System.out.println(s);
System.out.println(s.length());
boolean authenticated = false;
if (nbTry > 3) {
//Oops, enough!
}
if (s.length() != 4) {
System.out.println("Pin must be 4 digits");
} else {
System.out.println("Checking...");
//and check here!
ArrayList<Integer> pins = new ArrayList<Integer>();
readPinsData(new File("bdd.txt"), pins);
String[] thePins = new String[pins.size()];
for (int i = 0; i < thePins.length; i++) {
thePins[i] = pins.get(i).toString();
}
String passEntered = String.valueOf(jtf);
for (int i = 0; i < thePins.length; i++) {
if (passEntered.equals(thePins[i]) && jtf.getText().length() == 4) {
System.out.println(":)");
authenticated = true;
break;
}
}
if (authenticated) {
//Congratulation!
}
else {
nbTry++;
}
}
}
}
// Function to read/access my pins database (file bdd.txt)
static public boolean readPinsData(File dataFile, ArrayList<Integer> data) {
boolean err = false;
try {
Scanner scanner = new Scanner(dataFile);
String line;
while (scanner.hasNext()) {
line = scanner.nextLine();
try {
data.add(Integer.parseInt(line));
} catch (NumberFormatException e) {
e.printStackTrace();
err = true;
}
}
scanner.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
err = true;
}
return err;
}
public static void main(String[] args) {
Main fen = new Main();
}
}
答案 3 :(得分:0)
你的代码中有一个无限循环,所以当第一次调用BoutonListener.actionPerformed
时它只是旋转而不退出。
您必须对代码进行重大修改。首先将do-while条件中使用的变量提取到字段中,并在每次调用actionPerformed
时更新这些字段。
答案 4 :(得分:0)
您正在进入无限循环,因为用户没有机会重新输入他的PIN,如果它与长度不匹配。
循环和听众不会以这种方式工作得很好。为什么不将相关变量(例如nbTry
)保留为成员并执行检查而不循环?
答案 5 :(得分:0)
您的错误是if()
条件:
for (int i = 0; i < thePins.length; i++) {
if (passEntered.equals(thePins[i]) && jtf.getText().length() == 4) {
System.out.println(":)");
authenticated = true;
break;
}
}
由于你的pinCode的legnth不等于4,你永远不会验证条件,永远不会break
do-while()
循环。
顺便说一句,使用break
不是一个好主意,因为你总能找到一个允许你避免它的循环类型或条件!