Question

我有以下行动方法

public void actionPerformed(ActionEvent e) {

    Timer timer = new Timer();
    Object source = e.getSource();

    String stringfromDate = tffromDate.getText();
    String stringtoDate = tftoDate.getText();

    if (source == button) {
        // auto refresh begins
        int delay = 0; // 0 seconds startup delay
        int period = 7000; // x seconds between refreshes
        timer.scheduleAtFixedRate(new TimerTask()
        {
            @Override
            // i still have to truly understand what overide does however
            // netbeans prompted me to put this
            public void run() {

                try {
                    getdata(stringfromDate, stringtoDate);// run get data
                                                            // method
                } catch (IOException | BadLocationException ex) {
                    Logger.getLogger(JavaApplication63.class.getName())
                            .log(Level.SEVERE, null, ex);
                }
            }
        }, delay, period);
    }

    if (source == button1) {
        timer.cancel();

        textarea.setText("");
    }
}

我的GUI上有2个按钮，一个叫做获取信息（按钮），另一个叫做清除信息（按钮1）。我似乎无法得到我的清除信息（button1）来停止计时器并清除文本区域，以便可以执行新的搜索。我似乎无法让这个停止帮助赞赏。

Answer 1

考虑对代码的这些更改。主要是代码以不同的方式执行这些操作：

将计时器的声明提升到班级，以便之前启动的相同计时器可以在以后取消。

仅在按下开始按钮时才创建新计时器。

//Pulled up for access to make canceable .
protected Timer timer;

public void actionPerformed(ActionEvent e) {

  Object source = e.getSource();

  String stringfromDate = tffromDate.getText();
  String stringtoDate = tftoDate.getText();

  if (source == button) {
    //Stop existing one before creating new.
    if(timer != null) {
        timer.cancel();
    }
    //Now make new
    timer = new Timer();

    // auto refresh begins
    int delay = 0; // 0 seconds startup delay
    int period = 7000; // x seconds between refreshes
    timer.scheduleAtFixedRate(new TimerTask() {
        @Override 
        public void run() {

            try {
                getdata(stringfromDate, stringtoDate);// run get data
                                                        // method
            } catch (IOException | BadLocationException ex) {
                Logger.getLogger(JavaApplication63.class.getName()).log(Level.SEVERE, null, ex);

            }

        }
    }, delay, period);
  }
  if (source == button1) {          
    //NULLCHECK
    if(timer != null) {
        timer.cancel();
    }
    textarea.setText("");
  }
}

如何停止计时器

1 个答案: