Java Community | Help. Code. Learn.•5mo ago

Android Studio "temporal must not be null"

I'm very new to Java and coding in general (I started last week) and I'm making a calendar app for android. I got the basic calendar running, but when I tried to add a feature it keeps crashing. I believed it's because of line 119 always being null, but I initialised and declared it (I think). Anyways I'm stuck on this and can't work on my app anymore, so I would be very happy to solve this! Here's the error logcat message :

FATAL EXCEPTION: main Process: com.petris.lunor, PID: 2117 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.petris.lunor/com.petris.lunor.MainActivity}: java.lang.NullPointerException: temporal must not be null at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:4186) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4467) with tag AndroidRuntime

FATAL EXCEPTION: main Process: com.petris.lunor, PID: 2117 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.petris.lunor/com.petris.lunor.MainActivity}: java.lang.NullPointerException: temporal must not be null at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:4186) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:4467) with tag AndroidRuntime

77 Replies

JavaBot•5mo ago

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ayylmao123xdd•5mo ago

show how you assign the current display month value

PétrichorOP•5mo ago

One of these?

ayylmao123xdd•5mo ago

uhhh wait try in the assigning value just for testing do

PétrichorOP•5mo ago

Gemini told me to put a "defensive check" but idk if it's useful...

ayylmao123xdd•5mo ago

private LocalDate currentDisplayMonth = LocalDate.now()

private LocalDate currentDisplayMonth = LocalDate.now()

ai is dumb

PétrichorOP•5mo ago

I know 😭

ayylmao123xdd•5mo ago

try this in the main activity fields just for testing

PétrichorOP•5mo ago

It doesn't work Do you want the error message?

ayylmao123xdd•5mo ago

yea

PétrichorOP•5mo ago

message.txt

PétrichorOP•5mo ago

Oops

ayylmao123xdd•5mo ago

lmao

PétrichorOP•5mo ago

Why I can't paste :boohoo:

ayylmao123xdd•5mo ago

then screenshot

PétrichorOP•5mo ago

This line is so damn long

PétrichorOP•5mo ago

I can't put all of it

ayylmao123xdd•5mo ago

oh right android doesnt let you set the value lmao do you have the oncreate method show whats in there

PétrichorOP•5mo ago

Sorry if my code looks bad, I don't really know how to write yet...

ayylmao123xdd•5mo ago

dont worry i dont know how to either try this

@Override
protected void onCreate(Bundle savedInstanceState) {
  // super on create
  // set content view
  currentDisplayMonth = LocalDate.now()

}

@Override
protected void onCreate(Bundle savedInstanceState) {
  // super on create
  // set content view
  currentDisplayMonth = LocalDate.now()

}

and get rid of the local date now thing

PétrichorOP•5mo ago

Ok Still no :(

ayylmao123xdd•5mo ago

show error and paste the whole code

PétrichorOP•5mo ago

Which code

ayylmao123xdd•5mo ago

the class main activity just ctrl c and ctrl v here

PétrichorOP•5mo ago

message.txt

ayylmao123xdd•5mo ago

oh lmao when i typed this // super on create // set content view i meant you put the local date after these lines

PétrichorOP•5mo ago

ayylmao123xdd•5mo ago

add it between here

PétrichorOP•5mo ago

Ohh Mb Sorry what do I put there?

ayylmao123xdd•5mo ago

currentDisplayMonth = LocalDate.now()

PétrichorOP•5mo ago

Got it Damn, still not working

PétrichorOP•5mo ago

I think I broke it

PétrichorOP•5mo ago

These are my imports btw

PétrichorOP•5mo ago

So it should be able to detect the month and day, right?

ayylmao123xdd•5mo ago

one second let me check it on my version

PétrichorOP•5mo ago

Ofc

ayylmao123xdd•5mo ago

show the current code btw

PétrichorOP•5mo ago

I'll send a video If that's ok

ayylmao123xdd•5mo ago

i mean its gonna be faster if u just paste it i just need to check the on create method also what version of sdk do you have

PétrichorOP•5mo ago

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        currentDisplayMonth = LocalDate.now();
        setContentView(R.layout.activity_main);
        monthText = findViewById(R.id.monthText);
        yearText = findViewById(R.id.yearText);
        calendarGrid = findViewById(R.id.calendarGrid);
        Button prevMonthButton = findViewById(R.id.prevMonthButton);
        Button nextMonthButton = findViewById(R.id.nextMonthButton);
        if (monthText == null || yearText == null || calendarGrid == null || prevMonthButton == null || nextMonthButton == null) {
            Log.e("MainActivityLifecycle", "onCreate: One or more views are null!");
            return;
        }

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        currentDisplayMonth = LocalDate.now();
        setContentView(R.layout.activity_main);
        monthText = findViewById(R.id.monthText);
        yearText = findViewById(R.id.yearText);
        calendarGrid = findViewById(R.id.calendarGrid);
        Button prevMonthButton = findViewById(R.id.prevMonthButton);
        Button nextMonthButton = findViewById(R.id.nextMonthButton);
        if (monthText == null || yearText == null || calendarGrid == null || prevMonthButton == null || nextMonthButton == null) {
            Log.e("MainActivityLifecycle", "onCreate: One or more views are null!");
            return;
        }

Where can I check?

PétrichorOP•5mo ago

15 and 16?

ayylmao123xdd•5mo ago

in build.gradle file there should be minsdk

PétrichorOP•5mo ago

id 'com.android.application' version '8.11.0' apply false

ayylmao123xdd•5mo ago

wrong file there are 2 build.gradle

PétrichorOP•5mo ago

ayylmao123xdd•5mo ago

ok for testing purposes in default config add

defaultConfig {
  minSdk = 26

defaultConfig {
  minSdk = 26

PétrichorOP•5mo ago

Under targetSdk?

ayylmao123xdd•5mo ago

yes and then click sync now when gradle says files changed

PétrichorOP•5mo ago

Yes It's building

ayylmao123xdd•5mo ago

now try running the app again

PétrichorOP•5mo ago

It crashed

ayylmao123xdd•5mo ago

paste the code

PétrichorOP•5mo ago

message.txt

PétrichorOP•5mo ago

Wait

ayylmao123xdd•5mo ago

the code not the logs lmao

PétrichorOP•5mo ago

Which part

ayylmao123xdd•5mo ago

the whole class

PétrichorOP•5mo ago

message.txt

ayylmao123xdd•5mo ago

paste lines 90 - 110 cuz it throws error on those lines but i cant see which one it is cuz theres no imports

PétrichorOP•5mo ago

Oh right

    }
    }

    private void drawCalendar() {
        if (currentDisplayMonth == null) {
            Log.e("CalendarError", "drawCalendar() called but currentDisplayMonth is null! Initializing to now.");
            currentDisplayMonth = LocalDate.now(); // Fallback, but points to a deeper issue
        }
            Log.d("CalendarLifecycle", "drawCalendar() called for month: " + currentDisplayMonth.toString()); // New Log
            calendarGrid.removeAllViews();
            cellDateMap.clear();
        }

        YearMonth yearMonth = YearMonth.from(currentDisplayMonth);
        int daysInMonth = yearMonth.lengthOfMonth();
        LocalDate firstOfMonth = currentDisplayMonth.withDayOfMonth(1);
        DayOfWeek firstDayOfWeekEnum = firstOfMonth.getDayOfWeek();
        int dayOfWeekOfFirst = (firstDayOfWeekEnum == DayOfWeek.SUNDAY) ? 0 : firstDayOfWeekEnum.getValue();

         {

    }
    }

    private void drawCalendar() {
        if (currentDisplayMonth == null) {
            Log.e("CalendarError", "drawCalendar() called but currentDisplayMonth is null! Initializing to now.");
            currentDisplayMonth = LocalDate.now(); // Fallback, but points to a deeper issue
        }
            Log.d("CalendarLifecycle", "drawCalendar() called for month: " + currentDisplayMonth.toString()); // New Log
            calendarGrid.removeAllViews();
            cellDateMap.clear();
        }

        YearMonth yearMonth = YearMonth.from(currentDisplayMonth);
        int daysInMonth = yearMonth.lengthOfMonth();
        LocalDate firstOfMonth = currentDisplayMonth.withDayOfMonth(1);
        DayOfWeek firstDayOfWeekEnum = firstOfMonth.getDayOfWeek();
        int dayOfWeekOfFirst = (firstDayOfWeekEnum == DayOfWeek.SUNDAY) ? 0 : firstDayOfWeekEnum.getValue();

         {

ayylmao123xdd•5mo ago

and which one is the 103 line YearMonth yearMonth = YearMonth.from(currentDisplayMonth); this yes

PétrichorOP•5mo ago

Yes It's the line with the error in the problems

PétrichorOP•5mo ago

ayylmao123xdd•5mo ago

uno momento let me run it myself

PétrichorOP•5mo ago

Ofc

ayylmao123xdd•5mo ago

ok now i know everything basically you have this

    YearMonth yearMonth = YearMonth.from(currentDisplayMonth);
    int daysInMonth = yearMonth.lengthOfMonth();
    LocalDate firstOfMonth = currentDisplayMonth.withDayOfMonth(1);
    DayOfWeek firstDayOfWeekEnum = firstOfMonth.getDayOfWeek();
    int dayOfWeekOfFirst = (firstDayOfWeekEnum == DayOfWeek.SUNDAY) ? 0 : firstDayOfWeekEnum.getValue();

    YearMonth yearMonth = YearMonth.from(currentDisplayMonth);
    int daysInMonth = yearMonth.lengthOfMonth();
    LocalDate firstOfMonth = currentDisplayMonth.withDayOfMonth(1);
    DayOfWeek firstDayOfWeekEnum = firstOfMonth.getDayOfWeek();
    int dayOfWeekOfFirst = (firstDayOfWeekEnum == DayOfWeek.SUNDAY) ? 0 : firstDayOfWeekEnum.getValue();

outside of a method i assume it should be in the draw calendar method

    {
        // Add empty cells for days before the first of the month
        for (int i = 0; i < dayOfWeekOfFirst; i++) {
            addCellToGrid(null, false, null);
        }

        // Add cells for each day of the month
        for (int day = 1; day <= daysInMonth; day++) {
            LocalDate cellDate = currentDisplayMonth.withDayOfMonth(day);
            Log.d("CalendarLifecycle", "drawCalendar() - about to call addCellToGrid for: " + cellDate);
            addCellToGrid(String.valueOf(day), true, cellDate);
        }

        // Optional: Fill remaining cells
        int cellsInTypicalGrid = 42; // 7 columns * 6 rows
        if (calendarGrid.getColumnCount() > 0 && calendarGrid.getRowCount() > 0) {
            cellsInTypicalGrid = calendarGrid.getColumnCount() * calendarGrid.getRowCount();
        }
        int currentCellCount = calendarGrid.getChildCount();
        for (int i = currentCellCount; i < cellsInTypicalGrid; i++) {
            addCellToGrid(null, false, null);
        }
    }

    {
        // Add empty cells for days before the first of the month
        for (int i = 0; i < dayOfWeekOfFirst; i++) {
            addCellToGrid(null, false, null);
        }

        // Add cells for each day of the month
        for (int day = 1; day <= daysInMonth; day++) {
            LocalDate cellDate = currentDisplayMonth.withDayOfMonth(day);
            Log.d("CalendarLifecycle", "drawCalendar() - about to call addCellToGrid for: " + cellDate);
            addCellToGrid(String.valueOf(day), true, cellDate);
        }

        // Optional: Fill remaining cells
        int cellsInTypicalGrid = 42; // 7 columns * 6 rows
        if (calendarGrid.getColumnCount() > 0 && calendarGrid.getRowCount() > 0) {
            cellsInTypicalGrid = calendarGrid.getColumnCount() * calendarGrid.getRowCount();
        }
        int currentCellCount = calendarGrid.getChildCount();
        for (int i = currentCellCount; i < cellsInTypicalGrid; i++) {
            addCellToGrid(null, false, null);
        }
    }

also what is this supposed to do should it be in the draw calendar method it currently isnt thats why you get the errors because its not in any method if i assume right that it should be in the draw calendar then it should look like this

 private void drawCalendar() {
        if (currentDisplayMonth == null) {
            Log.e("CalendarError", "drawCalendar() called but currentDisplayMonth is null! Initializing to now.");
            currentDisplayMonth = LocalDate.now(); // Fallback, but points to a deeper issue
        }
        Log.d("CalendarLifecycle", "drawCalendar() called for month: " + currentDisplayMonth.toString()); // New Log
        calendarGrid.removeAllViews();
        cellDateMap.clear();

        YearMonth yearMonth = YearMonth.from(currentDisplayMonth);
        int daysInMonth = yearMonth.lengthOfMonth();
        LocalDate firstOfMonth = currentDisplayMonth.withDayOfMonth(1);
        DayOfWeek firstDayOfWeekEnum = firstOfMonth.getDayOfWeek();
        int dayOfWeekOfFirst = (firstDayOfWeekEnum == DayOfWeek.SUNDAY) ? 0 : firstDayOfWeekEnum.getValue();

        // Add empty cells for days before the first of the month
        for (int i = 0; i < dayOfWeekOfFirst; i++) {
            addCellToGrid(null, false, null);
        }

        // Add cells for each day of the month
        for (int day = 1; day <= daysInMonth; day++) {
            LocalDate cellDate = currentDisplayMonth.withDayOfMonth(day);
            Log.d("CalendarLifecycle", "drawCalendar() - about to call addCellToGrid for: " + cellDate);
            addCellToGrid(String.valueOf(day), true, cellDate);
        }

        // Optional: Fill remaining cells
        int cellsInTypicalGrid = 42; // 7 columns * 6 rows
        if (calendarGrid.getColumnCount() > 0 && calendarGrid.getRowCount() > 0) {
            cellsInTypicalGrid = calendarGrid.getColumnCount() * calendarGrid.getRowCount();
        }
        int currentCellCount = calendarGrid.getChildCount();
        for (int i = currentCellCount; i < cellsInTypicalGrid; i++) {
            addCellToGrid(null, false, null);
        }
    }

 private void drawCalendar() {
        if (currentDisplayMonth == null) {
            Log.e("CalendarError", "drawCalendar() called but currentDisplayMonth is null! Initializing to now.");
            currentDisplayMonth = LocalDate.now(); // Fallback, but points to a deeper issue
        }
        Log.d("CalendarLifecycle", "drawCalendar() called for month: " + currentDisplayMonth.toString()); // New Log
        calendarGrid.removeAllViews();
        cellDateMap.clear();

        YearMonth yearMonth = YearMonth.from(currentDisplayMonth);
        int daysInMonth = yearMonth.lengthOfMonth();
        LocalDate firstOfMonth = currentDisplayMonth.withDayOfMonth(1);
        DayOfWeek firstDayOfWeekEnum = firstOfMonth.getDayOfWeek();
        int dayOfWeekOfFirst = (firstDayOfWeekEnum == DayOfWeek.SUNDAY) ? 0 : firstDayOfWeekEnum.getValue();

        // Add empty cells for days before the first of the month
        for (int i = 0; i < dayOfWeekOfFirst; i++) {
            addCellToGrid(null, false, null);
        }

        // Add cells for each day of the month
        for (int day = 1; day <= daysInMonth; day++) {
            LocalDate cellDate = currentDisplayMonth.withDayOfMonth(day);
            Log.d("CalendarLifecycle", "drawCalendar() - about to call addCellToGrid for: " + cellDate);
            addCellToGrid(String.valueOf(day), true, cellDate);
        }

        // Optional: Fill remaining cells
        int cellsInTypicalGrid = 42; // 7 columns * 6 rows
        if (calendarGrid.getColumnCount() > 0 && calendarGrid.getRowCount() > 0) {
            cellsInTypicalGrid = calendarGrid.getColumnCount() * calendarGrid.getRowCount();
        }
        int currentCellCount = calendarGrid.getChildCount();
        for (int i = currentCellCount; i < cellsInTypicalGrid; i++) {
            addCellToGrid(null, false, null);
        }
    }

and then it wont crash anymore the problem was basically that the method calling get current month was not in any function and so the on create method was actually called later before this

  YearMonth yearMonth = YearMonth.from(currentDisplayMonth);
    int daysInMonth = yearMonth.lengthOfMonth();
    LocalDate firstOfMonth = currentDisplayMonth.withDayOfMonth(1);
    DayOfWeek firstDayOfWeekEnum = firstOfMonth.getDayOfWeek();
    int dayOfWeekOfFirst = (firstDayOfWeekEnum == DayOfWeek.SUNDAY) ? 0 : firstDayOfWeekEnum.getValue();

  YearMonth yearMonth = YearMonth.from(currentDisplayMonth);
    int daysInMonth = yearMonth.lengthOfMonth();
    LocalDate firstOfMonth = currentDisplayMonth.withDayOfMonth(1);
    DayOfWeek firstDayOfWeekEnum = firstOfMonth.getDayOfWeek();
    int dayOfWeekOfFirst = (firstDayOfWeekEnum == DayOfWeek.SUNDAY) ? 0 : firstDayOfWeekEnum.getValue();

thats why it was null even though you were checking if it isnt in many places

PétrichorOP•5mo ago

Sorry I was interrupted

PétrichorOP•5mo ago

Yayyy

PétrichorOP•5mo ago

Tysm!! Okok I understand now I need to check if it's in the correct void?

ayylmao123xdd•5mo ago

i would say you should assign the value in the on create method because inside it you have 2 methods using current display month so if you assign it there you wont need to check for that in the methods if its null

PétrichorOP•5mo ago

Alright I'll edit it tonight, I'm a bit busy this afternoon But thanks for solving it :)

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