CODEWITHSUNDEEP
javaandroid
user971741
user971741

Reputation:

findViewById throws null when called through an object

I have a function in main.java that uses some UI elements like spinner to textview.

public void updateNearByPeople() {
        reportEventPeopleAroundSpinner = (Spinner) findViewById(R.id.peopleAround);
        …
}

When I call this function from within class, it works fine.

But when I call this function from another class2.java through an object findViewById throws java.lang.NullPointerException

If I make the function and all variables in it static than it also works fine while calling from class2.java but it doesn’t work with object calls.

How can I solve this and made of object aware of the context?

In main.java:

protected void onCreate(final Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.main_view);

    mainAppContext = this;
    Main mainObj=new Main();
    gMapObj.initiateMap(mainAppContext,mainObj, mapFrag);
}

In class2.java:

public boolean initiateMap(Context appContext, Main mainObj, MapFragment mapFrag) {
        mainAppContext = appContext;
        mainAppObject = mainObj;
        …
        mainAppObject.updateNearByPeople();
    }

Upvotes: 0

Views: 67

Answers (1)

Blackbelt
Blackbelt

Reputation: 157437

Main mainObj=new Main();

you can't do that. The activity needs to go through its lifecycle, to build up its view hierarchy. If you just instantiate it through the new operator, neither its onAttach or onCreate method will be called. It means that you can not access resources and views as well

Upvotes: 1

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