如何创建一个片段计时器

Question

我本人是Android Studio的新手 运行该程序会打开一个窗口，然后立即关闭并写入已停止的应用程序 请查看错误在哪里 我在互联网上发现的那只猫，但该片段是“片段活动”，我试图更改片段v4 自己是猫https://codinginflow.com/tutorials/android/countdowntimer/part-4-time-input

public class FragmentTab1 extends Fragment {
    View view;
    private EditText mEditTextInput;
    private TextView mTextViewCountDown;
    private Button mButtonSet;
    private Button mButtonStartPause;
    private Button mButtonReset;

    private CountDownTimer mCountDownTimer;

    private boolean mTimerRunning;

    private long mStartTimeInMillis;
    private long mTimeLeftInMillis;
    private long mEndTime;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.tab1_fragment,container,false);

        mEditTextInput = getView().findViewById(R.id.edit_text_input);
        mTextViewCountDown = getView().findViewById(R.id.text_view_countdown);

        mButtonSet = getView().findViewById(R.id.button_set);
        mButtonStartPause = getView().findViewById(R.id.button_start_pause);
        mButtonReset = getView().findViewById(R.id.button_reset);

        mButtonSet.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String input = mEditTextInput.getText().toString();
                if (input.length() == 0) {
                    Toast.makeText(FragmentTab1.this.getContext(), "Field can't be empty", Toast.LENGTH_SHORT).show();
                    return;
                }

                long millisInput = Long.parseLong(input) * 60000;
                if (millisInput == 0) {
                    Toast.makeText(FragmentTab1.this.getContext(), "Please enter a positive number", Toast.LENGTH_SHORT).show();
                    return;
                }

                setTime(millisInput);
                mEditTextInput.setText("");
            }
        });

        mButtonStartPause.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mTimerRunning) {
                    pauseTimer();
                } else {
                    startTimer();
                }
            }
        });

        mButtonReset.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                resetTimer();
            }
        });
        return view;
    }

    private void setTime(long milliseconds) {
        mStartTimeInMillis = milliseconds;
        resetTimer();
        closeKeyboard();
    }

    private void startTimer() {
        mEndTime = System.currentTimeMillis() + mTimeLeftInMillis;

        mCountDownTimer = new CountDownTimer(mTimeLeftInMillis, 1000) {
            @Override
            public void onTick(long millisUntilFinished) {
                mTimeLeftInMillis = millisUntilFinished;
                updateCountDownText();
            }

            @Override
            public void onFinish() {
                mTimerRunning = false;
                updateWatchInterface();
            }
        }.start();

        mTimerRunning = true;
        updateWatchInterface();
    }

    private void pauseTimer() {
        mCountDownTimer.cancel();
        mTimerRunning = false;
        updateWatchInterface();
    }

    private void resetTimer() {
        mTimeLeftInMillis = mStartTimeInMillis;
        updateCountDownText();
        updateWatchInterface();
    }

    private void updateCountDownText() {
        int hours = (int) (mTimeLeftInMillis / 1000) / 3600;
        int minutes = (int) ((mTimeLeftInMillis / 1000) % 3600) / 60;
        int seconds = (int) (mTimeLeftInMillis / 1000) % 60;

        String timeLeftFormatted;
        if (hours > 0) {
            timeLeftFormatted = String.format(Locale.getDefault(),
                    "%d:%02d:%02d", hours, minutes, seconds);
        } else {
            timeLeftFormatted = String.format(Locale.getDefault(),
                    "%02d:%02d", minutes, seconds);
        }

        mTextViewCountDown.setText(timeLeftFormatted);
    }

    private void updateWatchInterface() {
        if (mTimerRunning) {
            mEditTextInput.setVisibility(View.INVISIBLE);
            mButtonSet.setVisibility(View.INVISIBLE);
            mButtonReset.setVisibility(View.INVISIBLE);
            mButtonStartPause.setText("Pause");
        } else {
            mEditTextInput.setVisibility(View.VISIBLE);
            mButtonSet.setVisibility(View.VISIBLE);
            mButtonStartPause.setText("Start");

            if (mTimeLeftInMillis < 1000) {
                mButtonStartPause.setVisibility(View.INVISIBLE);
            } else {
                mButtonStartPause.setVisibility(View.VISIBLE);
            }

            if (mTimeLeftInMillis < mStartTimeInMillis) {
                mButtonReset.setVisibility(View.VISIBLE);
            } else {
                mButtonReset.setVisibility(View.INVISIBLE);
            }
        }
    }

    private void closeKeyboard() {
        class Utils {
            public void hideKeyboard(@NonNull Activity activity) {
                View view = activity.getCurrentFocus();
                if (view != null) {
                    InputMethodManager imm = (InputMethodManager) activity.getSystemService( INPUT_METHOD_SERVICE );
                    imm.hideSoftInputFromWindow( view.getWindowToken() , 0 );
                }
            }
        }
    }


    @Override
    public void onStop() {
        super.onStop();

        SharedPreferences prefs = this.getActivity().getSharedPreferences("prefs", MODE_PRIVATE);
        SharedPreferences.Editor editor = prefs.edit();

        editor.putLong("startTimeInMillis", mStartTimeInMillis);
        editor.putLong("millisLeft", mTimeLeftInMillis);
        editor.putBoolean("timerRunning", mTimerRunning);
        editor.putLong("endTime", mEndTime);

        editor.apply();

        if (mCountDownTimer != null) {
            mCountDownTimer.cancel();
        }
    }

    @Override    public void onStart() {
        super.onStart();

        SharedPreferences prefs = this.getActivity().getSharedPreferences("prefs", MODE_PRIVATE);

        mStartTimeInMillis = prefs.getLong("startTimeInMillis", 600000);
        mTimeLeftInMillis = prefs.getLong("millisLeft", mStartTimeInMillis);
        mTimerRunning = prefs.getBoolean("timerRunning", false);

        updateCountDownText();
        updateWatchInterface();

        if (mTimerRunning) {
            mEndTime = prefs.getLong("endTime", 0);
            mTimeLeftInMillis = mEndTime - System.currentTimeMillis();

            if (mTimeLeftInMillis < 0) {
                mTimeLeftInMillis = 0;
                mTimerRunning = false;
                updateCountDownText();
                updateWatchInterface();
            } else {
                startTimer();
            }
        }
    }
}