Android studio highlights an area, without any errors in the code

Question

I'm new to android studio. I just added setOnItemSelectedListener for a Spinner and the background color of the code for listener turns brown (somehow like a selection):

What does this color mean? Is it normal or is it indicating a problem? And how can I make it go away because its really annoying.

i think these color shows null pointer exception in this code. check code for any missing . — Sangram Haladkar, Aug 19 '16 at 11:37
that color tells you that you could improve that code but it would still run. when you keep the mouse over it, what does the box say? — John Sardinha, Aug 19 '16 at 11:37
This seems like autogenerated block of code. Does typing anything in it remove it or it just stays there forever? :D Hover above it to see what the warning's all about..? — Vucko, Aug 19 '16 at 11:38
@JoãoSardinha it says that **Method invocation sp.... may produce java.lang.NullPointerException** but why? — Ashkan Mobayen Khiabani, Aug 19 '16 at 11:40
it is the default code, not written anything yet, what can be possibly be the cause of null pointer exception? — Ashkan Mobayen Khiabani, Aug 19 '16 at 11:42
becasue maybe you havent done the "sp = (Spinner)findViewById...", if you have that you can click "ignore issue" or something long those lines — John Sardinha, Aug 19 '16 at 11:42
this code is followed by `final Spinner sp = ((Spinner) findViewById(getResources().getIdentifier(ids[i], "id", getPackageName())));` — Ashkan Mobayen Khiabani, Aug 19 '16 at 11:44
Wild guess but I think variable `sp` can be null. Use `if(sp != null)` before setting the listener. — Ruben Weerts, Aug 19 '16 at 12:15

score 1 · Accepted Answer · edited May 23 '17 at 12:00

1

This is caused by the Android Studio trying to warn you that some method invocation may produce some exception (usually a NullPointerException). You can fix this by adding an if check for each thing like:

if(myThing != null){
    //do stuff
}

Or simply by adding before using myThing:

assert myThing != null;

Check this and maybe this question for further improving your insight on this.

edited May 23 '17 at 12:00

Community

1
1

answered Aug 19 '16 at 11:47

Vucko

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and myThins is?? is it the spinner? – Ashkan Mobayen Khiabani Aug 19 '16 at 11:48
It's anything. In your case a Spinner. It can be a Button, TextView, literally anything. – Vucko Aug 19 '16 at 11:49
1

Yep, that was it. Thanks a lot. – Ashkan Mobayen Khiabani Aug 19 '16 at 11:50
No problem, this thing annoys me as well sometimes. If you find a way to improve my post, feel free to edit it. – Vucko Aug 19 '16 at 11:50
1

Sure. but the answer seems to be complete although it is short. – Ashkan Mobayen Khiabani Aug 19 '16 at 11:51

score 0 · Answer 2 · answered Aug 19 '16 at 11:41

0

If you want to change the theme you can do it by File->Settings->Editor->Colors & Fonts-> In scheme name select Default and apply to see the white background of the studio.

answered Aug 19 '16 at 11:41

Dipali Shah

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It is not about theme, it is about an area being highlighted by the editor – Ashkan Mobayen Khiabani Aug 19 '16 at 11:43

Android studio highlights an area, without any errors in the code

2 Answers2