android - [Android]如何在Fragment中为AlertDialog设置final

Question

当我触摸 fragment 中的编辑文本时，我想使用 AlertDialog 来显示日历。过去，当我使用 Activity 类时，它工作得很好。但是当我使用 Fragment 时，它不起作用。

这是在 Fragment 中触摸编辑文本时显示日历对话框的方法:

 private void setDateTimeField() {
    try {
        et_date.setOnClickListener(this);

        final Calendar newCalendar = Calendar.getInstance();
        fromDatePickerDialog = new DatePickerDialog(this, new DatePickerDialog.OnDateSetListener() {
            public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
                Calendar newDate = Calendar.getInstance();
                newDate.set(year, monthOfYear, dayOfMonth - 1);
                if (newDate.getTime().getTime() > (newCalendar.getTime().getTime())) {

                    final  AlertDialog builder = new AlertDialog.Builder(getActivity()).setTitle("Notification").setMessage("This is a date of future! We will get current date for this review!").show();

                    //this code below is coppied in https://xjaphx.wordpress.com/2011/07/13/auto-close-dialog-after-a-specific-time/
                    final Timer t = new Timer();
                    t.schedule(new TimerTask() {
                        public void run() {
                            builder.dismiss(); // when the task active then close the dialog
                            t.cancel(); // also just top the timer thread, otherwise, you may receive a crash report
                        }
                    }, 2000); // after 2 second (or 2000 miliseconds), the task will be active.
                    et_date.setText(dateFormatter.format(newCalendar.getTime()));

                } else {
                    newDate.set(year, monthOfYear, dayOfMonth);
                    et_date.setText(dateFormatter.format(newDate.getTime()));
                }
            }
        }, newCalendar.get(Calendar.YEAR), newCalendar.get(Calendar.MONTH), newCalendar.get(Calendar.DAY_OF_MONTH));
    } catch (Exception ex) {
        messages("Something Wrong!");
    }
}

错在:

 final  AlertDialog builder = new AlertDialog.Builder(getActivity()).setTitle("Notification").setMessage("This is a date of future! We will get current date for this review!").show();

当我删除 final for builder 时，上面的代码没问题，但其他问题出现在:

builder.dismiss();

上面的代码要求构建器必须是最终的。我知道我的问题的最佳解决方案是使用 DialogFragment。但我不想使用它。此外，我想知道这个错误的原因。请帮我。p/s: 我的英语不好，如果我的语法有任何错误，我很抱歉，谢谢你阅读我的问题。

Answer 1

改变

fromDatePickerDialog = new DatePickerDialog(this, new DatePickerDialog.OnDateSetListener() {

到

fromDatePickerDialog = new DatePickerDialog(getActivity(), new DatePickerDialog.OnDateSetListener() {