Nullpointexception when try run app only after app was closed by system(Android)

Question

I noticed that my app only when is closed by system during open there is nullpointexception. Look I have Activity here I get data form db and create an object. Then I create new Fragment and set before created object to frament by setter. And use fragment manager to display fragment. Any here is a problem because in onCreate method field with my object is null. I am sure I seted object and it wasnt null.

Activity where I get data from db and create Fragment

public class ActivityForSingle extends AppCompatActivity {
  Employee emloyee;

  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_for_single);
    ...

    getEmployee(); // here I get emplyee from db and create employee object

    SitePersonFragment f = new SitePersonFragment();
            f.setEmpoyee(employee); // here emplyee is not null
            getSupportFragmentManager().beginTransaction().add(R.id.frameForFragment, f, "USER_SITE").commit();


}


public class SitePersonFragment extends Fragment implements Update, DatePickerDialog.OnDateSetListener {

 Employee employee;

  setEmployee(Employee e){
      this.emplyee = e;
  //here e and employee is not null
   }

  @Override
     public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);

  //here employee is null
  // why??
 }

What happend? I cannot debug because app is destroyed.

What do you mean "by system"? You shouldn't use System.exit methods — OneCricketeer, Jan 15 '17 at 17:48
And using setters on Fragments is often not recommended pattern for initializing objects. Please show your code as a [mcve] — OneCricketeer, Jan 15 '17 at 17:49
by Android. Android when need more ram close another witch are not used I meant. — JavaMan, Jan 15 '17 at 17:50

score 0 · Answer 1 · answered Jan 15 '17 at 21:02

0

  @Override
     public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);

    //here employee is null
    // why??
 }

Because the view might be created before you set the Employee.

Additionally, getEmployee()... does that return something? emloyee is never assigned in the code you posted. Why wouldn't it be null?

Related: Best practice for instantiating a new Android Fragment (requires a Serializable or Parcelable class)

answered Jan 15 '17 at 21:02

OneCricketeer

179,855
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I'll check it tomorow. I put log and check what is first but I think first is setting Employee and after is `onViewCreated() ` – JavaMan Jan 15 '17 at 21:05
Well, your question is not complete code, and it shouldn't compile, so I would recommend you fix that – OneCricketeer Jan 15 '17 at 21:06
It isnt complete but shows everything step by step. Of course there is `onCreateView` in Fragment. – JavaMan Jan 15 '17 at 21:09
You should make it complete, but minimal, as I commented above. For example, there is no `pracownikFragment` and you misspelled `employee` in one of the variables – OneCricketeer Jan 15 '17 at 21:16
I changed 'pracownikFragment ` to `f` – JavaMan Jan 15 '17 at 21:19

score 0 · Answer 2 · answered Jan 15 '17 at 21:18

0

I changed 'pracownikFragment tof`

answered Jan 15 '17 at 21:18

JavaMan

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Nullpointexception when try run app only after app was closed by system(Android)

2 Answers2