我正在嘗試制作一個可切換的按鈕來啟動和停止倒數計時器。它會啟動計時器但不會停止。我有點像 java 和 swing 之類的初學者，有人能幫忙嗎？這是一些代碼：private static Timer timer;timer = new Timer(1000, new ActionListener() { @Override public void actionPerformed(ActionEvent e) { l1.setText(Integer.toString(timeLeft / 60) + ":" + Integer.toString(timeLeft % 60)); timeLeft--; if (timeLeft == 0) { boolean rest = false; if (rest) { timeLeft = workTime; JOptionPane.showMessageDialog(null, "Times Up!"); rest = false; } else { timeLeft = restTime; JOptionPane.showMessageDialog(null, "Times Up!"); rest = true; } } }});b1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { boolean start = true; if (start == true){ timer.start(); b1.setText("stop"); start = false; } else if (start == false){ timer.stop(); //the part that doesn't work b1.setText("start"); start = true; } }});這不是確切的代碼，而是重要的部分
1 回答
弒天下
TA貢獻1818條經驗 獲得超8個贊
因為在 b1.addActionListener 上你設置了 boolean start = true; 這意味著每當你回到你的 actionPerformed 監聽器時，start = true你總是需要在 actionPerformed 之外聲明和初始化。
b1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
boolean start = true;
if (start == true){
timer.start();
b1.setText("stop");
start = false;
} else if (start == false){
timer.stop(); //the part that doesn't work
b1.setText("start");
start = true;
}
}
});
建議：您還可以聲明您的boolean start;類后并在默認構造函數中初始化start=true;，您可以在代碼中使用 start 變量。
或者簡單的 例子
private static Timer timer;
boolean start = true;
boolean rest = false;
timer = new Timer(1000, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
l1.setText(Integer.toString(timeLeft / 60) + ":" + Integer.toString(timeLeft % 60));
timeLeft--;
if (timeLeft == 0) {
if (rest) {
timeLeft = workTime;
JOptionPane.showMessageDialog(null, "Times Up!");
rest = false;
} else {
timeLeft = restTime;
JOptionPane.showMessageDialog(null, "Times Up!");
rest = true;
}
}
}
});
b1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (start == true){
timer.start();
b1.setText("stop");
start = false;
} else if (start == false){
timer.stop(); //the part that doesn't work
b1.setText("start");
start = true;
}
}
});
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