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Android

Posted by MUZ140837 Trust Mubaiwa
MUZ140837 Trust Mubaiwa
5,597 Points

Attempt to invoke virtual method '...' on a null object reference error

Hi. When i start the app while my network is off, i get an app crash when i click on the 7 day forecast button. i get the above error on the logs. please advise where i am am getting it wrong.

Seth Kroger
Seth Kroger
56,413 Points
Seth Kroger
Seth Kroger
56,413 Points

We need to see your code and the line that was causing the null reference to help.

MUZ140837 Trust Mubaiwa
MUZ140837 Trust Mubaiwa
5,597 Points

this is where the roor link is pointing me to

@OnClick(R.id.eventsButton) public void startEventsActivity(View view){ Intent intent = new Intent(this, EventsActivity.class); intent.putExtra(EVENT_UNIFIER, mUnifier.getEventUnified()); startActivity(intent); }

1 Answer

Seth Kroger
Seth Kroger
56,413 Points
Seth Kroger
Seth Kroger
56,413 Points

The most likely issue is mUnifier isn't initialized. Since you say this happens when your network is off, I'm guessing you are getting data from the net and initializing it when the response comes in. I'd recommend wrapping the code for starting the new activity in a if(mUnifier != null) statement. You can handle the else part however you like.

MUZ140837 Trust Mubaiwa
MUZ140837 Trust Mubaiwa
5,597 Points

thanks a lot its worked, i also did the following on the new activity:

Intent intent = getIntent(); if(intent.getParcelableArrayExtra(MainActivity.EVENT_UNIFIER) != null){ Parcelable[] parcelables = intent.getParcelableArrayExtra(MainActivity.EVENT_UNIFIER); int count = parcelables.length; if(count != 0){ mEvents = Arrays.copyOf(parcelables, count, Event[].class); EventAdapter adapter = new EventAdapter(this, mEvents); setListAdapter(adapter); }else{ EventAdapter adapter = new EventAdapter(this, mEvents); setListAdapter(adapter); } }

just to make sure that if a null is passed to the new activity it does not cause an error on the adapter