我正在使用按钮来启动和停止计时器。
我需要帮助解决这个问题......当我按下＆＃34;开始＆＃34;按钮有效（使用System.out.print进行测试）但setText没有为我更新。
但是，如果将t.start();放在frame.setVisible(true);之后而不是start = 1;之后，setText确实更新了...但是没有我按下＆＃34 ;开始＆＃34;按钮。如何在＆＃34;开始＆＃34;之后使setText更新？按下按钮？
public class Cook implements ActionListener{
private enum Actions {
Start, Stop, Setting, Exit
}
JLabel minsleft;
int start = 0, counter, stop = 0, close = 0, whileloop = 0;
JFrame frame = new JFrame("SMART STOVE");
public void Cook() {
Cook instance = new Cook();
// TODO Auto-generated method stub
JLabel minsleft = new JLabel();
minsleft.setFont(new Font("Serif", Font.BOLD, 17));
minsleft.setBounds(100,300,250,40);
try {
frame.setContentPane(new JLabel(new ImageIcon(ImageIO.read(new File("src\\cook.png")))));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
JButton Start = new JButton("Start");
Start.setFont(new Font("monospaced", Font.BOLD, 30));
Start.setActionCommand(Actions.Start.name());
Start.addActionListener(instance);
Start.setBounds(150, 180, 200, 100);
frame.add(Start);
JButton Stop = new JButton("Stop");
Stop.setFont(new Font("monospaced", Font.BOLD, 30));
Stop.setActionCommand(Actions.Stop.name());
Stop.addActionListener(instance);
Stop.setBounds(360, 180, 200, 100);
frame.add(Stop);
countdownLabel.setBounds(360, 250, 200, 100);
frame.add(countdownLabel);
frame.setLayout(null);
frame.setSize(700, 500);
frame.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent evt) {
// TODO Auto-generated method stub
if (evt.getActionCommand() == Actions.Start.name()) {
start = 1;
t.start();
}
if (evt.getActionCommand() == Actions.Stop.name()) {
close = 1;
}
System.out.println("Done");
}
final JLabel countdownLabel = new JLabel("Waiting. . . ");
public Timer t = new Timer(1000, new ActionListener() {
int time = 0;
@Override
public void actionPerformed(ActionEvent e) {
time++;
countdownLabel.setText(format(time / 60) + ":" + format(time % 60));
System.out.println(format(time / 60) + ":" + format(time % 60));
if (close == 1) {
final Timer timer = (Timer) e.getSource();
timer.stop();
System.out.println("Stopped");
}
}
});
private static String format(int i) {
String result = String.valueOf(i);
if (result.length() == 1) {
result = "0" + result;
}
return result;
}
}
答案 0 :(得分：0)
我想知道你是如何运行代码的，而没有main。所以我添加了一个
public static void main(String[] args) {
new Cook().Cook();
}
然后我想知道你为什么要在Cook方法中创建新的Cook实例（非常糟糕的Java命名）。
Cook instance = new Cook();
所以我删除了它并将Start.addActionListener(instance);更改为Start.addActionListener(this);，现在它正在运行......
我还会添加默认关闭操作，否则它不会真正关闭...
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
完整代码：
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.Timer;
public class Cook implements ActionListener{
private enum Actions {
Start, Stop, Setting, Exit
}
JLabel minsleft;
int start = 0, counter, stop = 0, close = 0, whileloop = 0;
JFrame frame = new JFrame("SMART STOVE");
public void Cook() {
// Cook instance = new Cook();
// TODO Auto-generated method stub
JLabel minsleft = new JLabel();
minsleft.setFont(new Font("Serif", Font.BOLD, 17));
minsleft.setBounds(100,300,250,40);
try {
frame.setContentPane(new JLabel(new ImageIcon(ImageIO.read(new File("src\\cook.png")))));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
JButton Start = new JButton("Start");
Start.setFont(new Font("monospaced", Font.BOLD, 30));
Start.setActionCommand(Actions.Start.name());
Start.addActionListener(this);
Start.setBounds(150, 180, 200, 100);
frame.add(Start);
JButton Stop = new JButton("Stop");
Stop.setFont(new Font("monospaced", Font.BOLD, 30));
Stop.setActionCommand(Actions.Stop.name());
Stop.addActionListener(this);
Stop.setBounds(360, 180, 200, 100);
frame.add(Stop);
countdownLabel.setBounds(360, 250, 200, 100);
frame.add(countdownLabel);
frame.setLayout(null);
frame.setSize(700, 500);
frame.setVisible(true);
}
@Override
public void actionPerformed(ActionEvent evt) {
// TODO Auto-generated method stub
if (evt.getActionCommand() == Actions.Start.name()) {
start = 1;
t.start();
}
if (evt.getActionCommand() == Actions.Stop.name()) {
close = 1;
}
System.out.println("Done");
}
final JLabel countdownLabel = new JLabel("Waiting. . . ");
public Timer t = new Timer(1000, new ActionListener() {
int time = 0;
@Override
public void actionPerformed(ActionEvent e) {
time++;
countdownLabel.setText(format(time / 60) + ":" + format(time % 60));
System.out.println(format(time / 60) + ":" + format(time % 60));
if (close == 1) {
final Timer timer = (Timer) e.getSource();
timer.stop();
System.out.println("Stopped");
}
}
});
private static String format(int i) {
String result = String.valueOf(i);
if (result.length() == 1) {
result = "0" + result;
}
return result;
}
public static void main(String[] args) {
new Cook().Cook();
}
}