Null Pointer Exception on Split()

Question

Hey guys I am working on a simple To-do list app for an assignment. In my app there is an error which occurs when I click the listView item. It is supposed to open a dialog in which I can edit the item. However, instead the app crashes and this error message is shown:

10-18 09:01:24.463 12767-12767/com.example.ayush.todolistapp E/AndroidRuntime: FATAL EXCEPTION: main
                                                                           Process: com.example.ayush.todolistapp, PID: 12767
                                                                           java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String[] java.lang.String.split(java.lang.String)' on a null object reference
                                                                               at com.example.ayush.todolistapp.MainActivity.fillReplaceDialog(MainActivity.java:140)
                                                                               at com.example.ayush.todolistapp.MainActivity$2.onItemClick(MainActivity.java:56)
                                                                               at android.widget.AdapterView.performItemClick(AdapterView.java:310)
                                                                               at android.widget.AbsListView.performItemClick(AbsListView.java:1147)
                                                                               at android.widget.AbsListView$PerformClick.run(AbsListView.java:3068)
                                                                               at android.widget.AbsListView$3.run(AbsListView.java:3916)
                                                                               at android.os.Handler.handleCallback(Handler.java:739)
                                                                               at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                               at android.os.Looper.loop(Looper.java:152)
                                                                               at android.app.ActivityThread.main(ActivityThread.java:5497)
                                                                               at java.lang.reflect.Method.invoke(Native Method)
                                                                               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

I am not able to find the root of the problem and so it would be really helpful if someone could help me out. Here is the mainActivity file :

    public class MainActivity extends AppCompatActivity {

    Dialog dialog;
    myDatabase database = new myDatabase(this);
    ArrayList<Data> list = new ArrayList<>();
    int numberOfItems = 0;
    ListView listView;
    EditText et1;
    EditText et2;
    DatePicker dp1;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        listView = (ListView) findViewById(R.id.mylist);
        list = database.returnProduct();
        CustomAdapter adapter = new CustomAdapter(MainActivity.this,list);
        listView.setAdapter(adapter);

        listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
                database.setAsComplete(position);
                Toast.makeText(MainActivity.this, "Item saved as completed", Toast.LENGTH_SHORT).show();
                return false;
            }
        });
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                fillReplaceDialog(position);
                String title = list.get(position).getTitle();
                String desc = list.get(position).getDescription();
                String final_date = list.get(position).getDueDate();
                String[] date = final_date.split("/");//here is where the error is occurring
                int day = Integer.parseInt(date[0]);
                int month = Integer.parseInt(date[1]);
                int year = Integer.parseInt(date[2]);
                et1.setText(title);
                et2.setText(desc);
                dp1.updateDate(year,month,day);

            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        if (id == R.id.completed_tasks){
            Intent intent = new Intent(MainActivity.this, Main2Activity.class);
            startActivity(intent);
        }
        else if (id == R.id.add_items){
            fillDialog();
        }

        return super.onOptionsItemSelected(item);
    }

    public void fillDialog(){

        dialog = new Dialog(this);
        dialog.setCanceledOnTouchOutside(false);
        dialog.setContentView(R.layout.dialog_layout);
        dialog.show();
        Button bt_save= (Button) dialog.findViewById(R.id.button);
        listView = (ListView) findViewById(R.id.mylist);
        et1 = (EditText) dialog.findViewById(R.id.et_title);
        et2 = (EditText) dialog.findViewById(R.id.et_description);
        dp1= (DatePicker) dialog.findViewById(R.id.datePicker);
        bt_save.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String title = et1.getText().toString();
                String description = et2.getText().toString();
                int day = dp1.getDayOfMonth();
                int month = dp1.getMonth();
                int year = dp1.getYear();
                String final_date = day+"/"+month+"/"+year;
                database.insert_Data(title,description,final_date);
                numberOfItems+=1;
                dialog.dismiss();
                list = database.returnProduct();
                CustomAdapter adapter = new CustomAdapter(MainActivity.this,list);
                listView.setAdapter(adapter);
            }
        });
        Button bt_cancel = (Button) dialog.findViewById(R.id.button2);
        bt_cancel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //automatically dismisses the dialog on pressing the cancel button
                dialog.dismiss();
            }
        });
    }

    public void fillReplaceDialog(final int position){
        dialog = new Dialog(this);
        dialog.setCanceledOnTouchOutside(false);
        dialog.setContentView(R.layout.dialog_layout);
        dialog.show();
        Button bt_save= (Button) dialog.findViewById(R.id.button);
        listView = (ListView) findViewById(R.id.mylist);
        et1 = (EditText) dialog.findViewById(R.id.et_title);
        et2 = (EditText) dialog.findViewById(R.id.et_description);
        dp1= (DatePicker) dialog.findViewById(R.id.datePicker);
        bt_save.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String title = et1.getText().toString();
                String description = et2.getText().toString();
                int day = dp1.getDayOfMonth();
                int month = dp1.getMonth();
                int year = dp1.getYear();
                String final_date = day+"/"+month+"/"+year;
                database.replaceObject(title,description,final_date, position);
                dialog.dismiss();
                list = database.returnProduct();
                CustomAdapter adapter = new CustomAdapter(MainActivity.this,list);
                listView.setAdapter(adapter);
            }
        });
        Button bt_cancel = (Button) dialog.findViewById(R.id.button2);
        bt_cancel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //automatically dismisses the dialog on pressing the cancel button
                dialog.dismiss();
            }
        });
    }
}

Data Class:

 public class Data {

    String title;
    String description;
    String dueDate;
    int status;

    public String getTitle() {
        return title;
    }

    public String getDescription() {
        return description;
    }

    public String getDueDate() {
        return dueDate;
    }

    public int getStatus() {
        return status;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public void setDueDate(String dueDate) {
        this.dueDate = dueDate;
    }

    public void setStatus(int status) {
        this.status = status;
    }
}

CustomAdapter class:

 public class CustomAdapter extends BaseAdapter {
    private Context mContext;
    private ArrayList<Data> mData;
    LayoutInflater mInflator;

    public CustomAdapter(Context context, ArrayList<Data> list){
        mContext = context;
        mData = list;
        mInflator = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }


    @Override
    public int getCount() {
        return mData.size();
    }

    @Override
    public Object getItem(int position) {

        return mData.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        convertView = mInflator.inflate(R.layout.row_layout, parent, false);
        //inflates the layout
        TextView tv1 = (TextView) convertView.findViewById(R.id.textView);
        TextView tv2 = (TextView) convertView.findViewById(R.id.textView2);
        TextView tv3 = (TextView) convertView.findViewById(R.id.textView3);
        TextView header = (TextView) convertView.findViewById(R.id.header_title);
        ImageView iv1 = (ImageView) convertView.findViewById(R.id.imageView);
        tv1.setText(mData.get(position).getTitle());
        tv2.setText(mData.get(position).getDescription());
        tv3.setText(mData.get(position).getDueDate());
        iv1.setImageResource(R.drawable.incomplete);
        header.setText(mData.get(position).getDueDate());
        return convertView;
        //returns the view
    }
}

I'm only a beginner and have only recently started learning android programming so please excuse any silly mistakes. Thanks in advance

You need to check `final_date` value first through logcat, I think it might be null. — kimkevin, Oct 18 '17 at 03:47
without seeing your CustomAdapter it is really hard to know where your problem actually is. I believe that in your custom adapter, if your item didn't have a due date already it is going to be null, so you either need a null check when displaying it and show something like "not set" or do that in your custom adapter. it is your custom adapter class anyways where you probably should fix it. — Lassi Kinnunen, Oct 18 '17 at 04:07
and also, maybe you can show us what is `Data` class looks like? — Komang Sidhi Artha, Oct 18 '17 at 04:15
hm.. what about `database.returnProduct()`? can you show us the code? I believe that you haven't set all field of the data instance when you instantiate them on `database.returnProduct()` — Komang Sidhi Artha, Oct 18 '17 at 07:01
ah yes as @MikeM. said, the problem seem to be in `fillReplaceDialog()` method on stack trace — Komang Sidhi Artha, Oct 18 '17 at 07:03
`final_date` was null. You failed to check for it. Duplicate. — user207421, Oct 18 '17 at 09:24

IntelliJ Amiya · Accepted Answer · 2017-10-18T09:17:24.143

 java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String[] java.lang.String.split(java.lang.String)' on a null object reference

NullPointerException is thrown when an application attempts to use an object reference that has the null value.

Problem Coming from

String final_date = list.get(position).getDueDate(); // At first value getting null
String[] date = final_date.split("/"); // Didn't find "/" in STRING that's why CRASHING .

FYI, Run your APP in DEBUG mode. You can find answer.

final_date is null. You should check checking STRING null or not .

if (final_date != null && !final_date.isEmpty())
{
 String[] date = final_date.split("/");
  ........// Your code //............
}
else
{
  // Your String null ;
}

score 0 · Answer 2 · answered Oct 18 '17 at 06:05

0

Try printing the value final_date in console. I think getDueDate() returning the null i.e Item may not having the due date.

answered Oct 18 '17 at 06:05

user3438583

155
1
2
8

score -2 · Answer 3 · answered Oct 18 '17 at 04:10

-2

Check DateFormat is ("dd/mm/yyyy") proper or not. if / is not found in DateFormat then final_date.split("/") is not work.

You can also get the day, month, year like this.

  DateFormat formatter = new SimpleDateFormat("MM/dd/yyyy");
  Date date = formatter.parse("10/18/2017");  
  int month = date.getMonth();
  int day= date.getDay();
  int year = date.getYear();

answered Oct 18 '17 at 04:10

Jigar Patel

1,550
2
13
29

How is date format related? Check my comment on the question. – NewUser Oct 18 '17 at 04:13
@NewUser have you read the question? – Jigar Patel Oct 18 '17 at 04:15
If `/` is not found in the source then split returns an array with one element in it which would be the whole source string. However, `null.split("")` will always throw a `NPE`. Hope this clarifies. – NewUser Oct 18 '17 at 04:19

Null Pointer Exception on Split()

3 Answers3