Java 完成时间选择器时调用非静态函数

我对安卓有点陌生，我现在正和时间选择器打交道。我这里有一个计时器：

public class TimePickerFragment extends DialogFragment
    implements TimePickerDialog.OnTimeSetListener {

    public String time;
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // Use the current time as the default values for the picker
        final Calendar c = Calendar.getInstance();
        int hour = c.get(Calendar.HOUR_OF_DAY);
        int minute = c.get(Calendar.MINUTE);

        // Create a new instance of TimePickerDialog and return it
        return new TimePickerDialog(getActivity(), this, hour, minute,
            DateFormat.is24HourFormat(getActivity()));
    }

    public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
        // Do something with the time chosen by the user
        time = hourOfDay + ":" + minute;
        //update global variable
        MockDB.setCheckout(time);
    }
}

这是可行的，但在用户选择了一个时间后，我想调用活动中的一个函数，选择器正在更改按钮颜色和文本。这在一个名为ReserveProduct的函数中，该函数扩展了AppCompatActivity

public void animateButtons() {
    //picker disappears until next button is clicked
    Button picker = (Button) findViewById(R.id.button6);
    picker.setVisibility(View.GONE);
    Button picker1 = (Button) findViewById(R.id.button7);
    picker1.setVisibility(View.GONE);
    if (settingReturn == false) {
        //first button turns gray
        Button bttn1 = (Button) findViewById(R.id.buttonCheckIn);
        bttn1.setBackgroundResource(R.drawable.button_inactive);
        String time = ((MockDB) this.getApplication()).getCheckout();
        bttn1.setText("Check Out: 12:27 PM");
        //new button appears
        Button bttn2 = (Button) findViewById(R.id.buttonCheckOut);
        bttn2.setVisibility(View.VISIBLE);
        settingReturn = true;
    } else {
        //make 2nd button inactive
        Button bttn2 = (Button) findViewById(R.id.buttonCheckOut);
        bttn2.setBackgroundResource(R.drawable.button_inactive);
        String time = ((MockDB) this.getApplication()).getReturn();
        bttn2.setText("Return: 1:27 PM");
        //show new buttons
        Button set = (Button) findViewById(R.id.buttonSet);
        set.setVisibility(View.VISIBLE);
        Button home = (Button) findViewById(R.id.buttonHome);
        home.setVisibility(View.VISIBLE);

    }
}

我的问题是这个函数不是静态的，所以我不能简单地从TimePicker类调用它。我无法将按钮更改功能移动到TimePicker类，因为我需要能够扩展AppCompatActivity，但AppCompatActivity和DialogFragment有一个冲突的类。我也不能使animateButtons类保持静态，因为findViewById功能会抛出一个错误

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请帮忙

首先实例化类，即

(new SomeClass()).someMethod();

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我尝试了这个，虽然它不再抛出错误，但当我在时间选择器中点击ok时，应用程序正在崩溃