How do you use the putExtra() and getExtras() code to get an int value?

Question

What the title says, I've tried below but it didn't work. Also where should I put the getExtras() in MainActivity.class? I tried it both outside and inside OnCreate() but my app keeps crashing upon startup. I can't find an error with it crashing either.

SettingsActivity.class

public void onClick(View v) {
                Intent intent = new Intent(SettingsActivity.this, MainActivity.class);
                intent.putExtra("isMeasurement", 2);
                startActivity(intent);
            }

MainActivity.class

public int isMeasurement = getIntent().getExtras().getInt("isMeasurement");

That doesn't make any sense? There should be some code in MainActivity, and some code in SettingsActivity which is what I have — Flies, Apr 05 '19 at 13:17
You shouldn't call `getIntent()` before `onCreate()` which seems to happen here when you initialize the `public int isMeasurement` field. See: https://stackoverflow.com/a/13984384/6761823 — Andrzej Zabost, Apr 05 '19 at 13:18
@Flies is it your data flow like MainActivity->SettingsActivity->MainActivity ???? — Basi, Apr 05 '19 at 13:28
Yeah, but I have it all fixed now, thanks guys :) Also, is there something wrong with my questions (like being too dumb or something)? They get downvoted all the time. Not anything to worry about, just curious — Flies, Apr 05 '19 at 13:32

p.mathew13 · Accepted Answer · 2019-04-05T13:28:34.113

2

This is how you should pass data

Intent intent = new Intent(SettingsActivity.this, MainActivity.class);
            intent.putExtra("isMeasurement", 2);
            startActivity(intent);

Inside your onCreate

This is how you can retrieve data in MainActivity

int isMeasurement = getIntent().getIntExtra("isMeasurement",0); // Here 0 is a default value.It could be anything acc to your requirement

edited Apr 05 '19 at 13:28

answered Apr 05 '19 at 13:16

p.mathew13

920
8
16

It doesn't change the fact that `getIntent()` should not be called before `onCreate()`. See: https://stackoverflow.com/a/13984384/6761823 – Andrzej Zabost Apr 05 '19 at 13:21
I never mentioned that getIntent() should be called before onCreate. Sorry if my answer was not clear. Have edited it to remove any confusion. – p.mathew13 Apr 05 '19 at 13:25
Yes, but `public int isMeasurement` clearly indicates it's a field that gets evaluated before `onCreate()`. You can't use the `public` modifier like this inside a method. – Andrzej Zabost Apr 05 '19 at 13:27
1

you are correct. My mistake for not noticing it before. Thanks for pointing it out @AndrzejZabost – p.mathew13 Apr 05 '19 at 13:29

score 0 · Answer 2 · answered Apr 05 '19 at 13:24

0

There is problem in your getting data in other activity. The correct way to do is mentioned below :

@Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
    int isMeasurement = getIntent().getIntExtra("isMeasurement",0);
}

answered Apr 05 '19 at 13:24

Hitesh Sarsava

666
4
15

score 0 · Answer 3 · answered Apr 05 '19 at 13:26

SettingsActivity:

Intent intent = new Intent(SettingsActivity.this, MainActivity.class);
            intent.putExtra("isMeasurement", 2);
            startActivity(intent);

and

MainActivity:

@Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
    int isMeasurement = getIntent().getIntExtra("isMeasurement",0);
}

How do you use the putExtra() and getExtras() code to get an int value?

3 Answers3