使用 cancel() 后通知关闭并重新打开；答案

【问题标题】：Notification closed and reopened after using cancel();使用 cancel() 后通知关闭并重新打开；
【发布时间】：2018-09-05 13:06:19
【问题描述】：

我的应用有问题。我有 2 个按钮开始和停止，当我单击开始时，会在倒数计时器的每个刻度中创建和更新通知，但是我想在按下停止按钮时关闭通知。我使用了 notificationmanager.cancel(id) 但通知已关闭并再次打开。我做错了什么？这是我的代码：

private void startButtonClick() {
    try {
        time = Integer.parseInt(timeInMinutes.getText().toString());
        if (time == 0) {
            throw new NumberFormatException("Time can't be lower than 1");
        }
        startButton.setVisibility(View.INVISIBLE);
        pauseButton.setVisibility(View.VISIBLE);
        timeInMinutes.setVisibility(View.INVISIBLE);
        countDownTextView.setVisibility(View.VISIBLE);
        final NotificationCompat.Builder mBuilder =
                new NotificationCompat.Builder(this)
                        .setSmallIcon(R.mipmap.ic_launcher)
                        .setLargeIcon(BitmapFactory.decodeResource(getApplicationContext().getResources(), R.mipmap.ic_launcher))
                        .setContentTitle("Timer")
                        .setContentText("12312312");
        notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        new CountDownTimer(time * 60000, 500) {
            public void onTick(long millisUntilFinished) {
                if (isCanceled) {
                    cancel();
                    buttonsVisibility();
                    isCanceled = false;
                }
                int minutes = (int) (millisUntilFinished / 1000) / 60;
                int seconds = (int) (millisUntilFinished / 1000) % 60;
                countDownTextView.setText("Time left: " + String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds));
                mBuilder.setContentText("Time left: " + String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds));
                notificationManager.notify(3, mBuilder.build());
            }

            public void onFinish() {
                turnOffBluetooth();
                turnOffWiFi();
                turnOffAudio();
                turnOnSilentMode();
                buttonsVisibility();
                notificationManager.cancel(3);
            }
        }.start();
    }
    catch (NumberFormatException e){
        Toast.makeText(getApplicationContext(), "Enter time. Only numbers!", Toast.LENGTH_SHORT).show();
    }
}
private void pauseButtonClick() {
    Toast.makeText(getApplicationContext(), "Timer off", Toast.LENGTH_LONG).show();
    startButton.setVisibility(View.VISIBLE);
    pauseButton.setVisibility(View.INVISIBLE);
    isCanceled = true;
    NotificationManager notificationManager = (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
    notificationManager.cancel(3);
}

【问题讨论】：

标签： java android countdown

【解决方案1】：

即使您取消了计时器，您还没有完成该方法，因此它将继续执行以避免您可以尝试此操作

if (isCanceled) {
                    cancel();
                    isCanceled = false;
                } else {
                    int minutes = (int) (millisUntilFinished / 1000) / 60;
                    int seconds = (int) (millisUntilFinished / 1000) % 60;
                    mBuilder.setContentText(
                        "Time left: " + String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds));
                    notificationManager.notify(3, mBuilder.build());
                }

【讨论】：

【解决方案2】：

像这样修改 onTick() 方法：

public void onTick(long millisUntilFinished) {
      if (isCanceled) {
          cancel();
          buttonsVisibility();
          //isCanceled = false;   //comment or delete this line               
      }else{
          int minutes = (int) (millisUntilFinished / 1000) / 60;
          int seconds = (int) (millisUntilFinished / 1000) % 60;
          countDownTextView.setText("Time left: " + String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds));
          mBuilder.setContentText("Time left: " + String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds));
          notificationManager.notify(3, mBuilder.build()); //only notify when isCanceled is false
      }                    
}

【讨论】：