使用getText（）获取Button的文本，即

String text = timePickerBTN.getText().toString();

您的代码如下所示

timePickerBTN.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                TimePickerDialog timePickerDialog =  new TimePickerDialog(NewTaskActivity.this, new TimePickerDialog.OnTimeSetListener() {

                    @Override
                    public void onTimeSet(TimePicker timePicker, int hourOfDay, int Minute) {
                        TimeHour = hourOfDay;
                        TimeMinute = Minute;

                        Calendar calendarTime = Calendar.getInstance();
                        calendarTime.set(0,0,0, TimeHour, TimeMinute);
                        timePickerBTN.setText(android.text.format.DateFormat.format("hh:mm aa", calendarTime));
                        text = timePickerBTN.getText().toString();

                    }

                },12,0,false);

                timePickerDialog.updateTime(TimeHour, TimeMinute);
                timePickerDialog.show();

            }

        });