Pass a string variable from an activity into a fragment

Question

Hi I'm trying to pass a string variable from an activity into a fragment but it's always null.

Firstly I set the variable value, then create the bundle in the Activity:

String results = setResultCaption(bothEarsBad, leftEarBad, rightEarBad).toString();

Then

Bundle bundle = new Bundle();
bundle.putString("resultsString", results);
RightEarResults rightEarResults = new RightEarResults();
rightEarResults.setArguments(bundle);

I then call the bundle from the fragment onCreateView method as follows:

String bundle = getArguments().getString("resultsString");

And then set the variable in the TextView

txt = (TextView) rootView.findViewById(R.id.results_text);
txt.setText(bundle);

Can anyone help me understand why it's always null.

Your code looks alright. can refer this http://stackoverflow.com/questions/12739909/send-data-from-activity-to-fragment-in-android — Raghunandan, Mar 14 '14 at 15:53

Philipp Jahoda · Accepted Answer · 2014-03-14T16:01:25.563

1

Provide a newInstance() method for your Fragment and hand over the parameter there:

public static YourFragment newInstance(String valueToPass) {

   YourFragment f = new YourFragment();

   Bundle b = new Bundle();
   b.putString("key", valueToPass);
   f.setArguments(b);

   return f;
}

In your Actitity:

getSupportFragmentManager().beginTransaction().replace(R.id.container, YourFragment.newInstance(stringtoPass), "yourFragTag").commit();

Inside your Fragment, you can then retrieve the value by using the getArguments() method:

String yourvalue = getArguments().getString("key");

EDIT : Also, please check if your setResultCaption(...) method actually returns something, and not NULL.

edited Mar 14 '14 at 16:01

answered Mar 14 '14 at 15:55

Philipp Jahoda

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thanks for the help! so will I still have to call FragmentTransaction.add in the activity? – Paddy1990 Mar 15 '14 at 01:00
Yes you can use add instead of replace as well. – Philipp Jahoda Mar 15 '14 at 01:50
the part I don't really get is what I pass into 'replace(R.id.container, YourFragment.newInstance(stringtoPass), "yourFragTag")' what is the R.id.container, is it the textview i want to pass the string into? and "yourFragtag" is that just a string in my fragment? I created a string called 'public static final String IS_RIGHT_EAR = "is_right_ear";' is this what i pass in and do I bass the value or the reference? – Paddy1990 Mar 15 '14 at 09:19
R.id.container is the layout in your .xml file that will contain the Fragment. Usually, a FrameLayout is used for that. – Philipp Jahoda Mar 15 '14 at 09:27
"yourFragTag" is a tag for your Fragment, an identifier that will enable you to find your Fragment and access it. It is not really needed in your case. – Philipp Jahoda Mar 15 '14 at 11:29
The string is now passed into the interface on the fragment, but returns null at 'resultTxt = getArguments().getString("key");' how can that be? – Paddy1990 Mar 15 '14 at 17:41

score 0 · Answer 2 · answered Mar 14 '14 at 16:13

If you want to pass variables on fragment initialisation, you can :

Use a bundle as parameter of Fragment.setArgument() method
Use a static method with your variables as parameters. Check @Philipp Jahoda's answer.

If you want to pass variables to fragment after initialisation, you can refer to this post from the official doc

score 0 · Answer 3 · answered Mar 15 '14 at 14:12

You can just do:

From your activity;

Intent passIntent = new Intent(MainActivity.this, Yourclass.class);
passIntent.addExtra("resultsString",results);
startActivity(passIntent);

In your fragment;

Intent intentBundle = getActivity().getIntent();
        String someresult= intentBundle.getStringExtra("resultsString");
        Log.i("Result : ", someresult);

And then,

txt = (TextView) rootView.findViewById(R.id.results_text);
txt.setText(someresult);

Pass a string variable from an activity into a fragment

3 Answers3