Refresh Fragment Views based on Button Click

Question

I have 2 fragments (tabs) that share some data. When one changes the data, I'd like to have that reflected on the other tab. I researched this on stackOverflow and I think the relevant answer has to do with a .notifyDataSetChanged() call, but I can't make it work. Here's the relevant code...

public class EnterCourseData extends FragmentActivity implements ActionBar.TabListener {

private ViewPager viewPager;
private TabsPagerAdapter mAdapter;
private ActionBar actionBar;
// Tab titles
private String[] tabs = { "Pars", "Handicaps" };
private int courseNumber, teeNumber;
private Tee tee;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_enter_tees);
    // Initilization
    Intent mIntent = getIntent();
    courseNumber = mIntent.getIntExtra("courseNumber",0);
    Course course = Global.getCourse(courseNumber);
    teeNumber = mIntent.getIntExtra("teeNumber",0);
    tee = course.getTee(teeNumber);

    viewPager = (ViewPager) findViewById(R.id.pager);
    actionBar = getActionBar();
    mAdapter = new TabsPagerAdapter(getSupportFragmentManager(), courseNumber, teeNumber);

    viewPager.setAdapter(mAdapter);
    actionBar.setHomeButtonEnabled(false);
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);        

    // Adding Tabs
    for (String tab_name : tabs) {
        actionBar.addTab(actionBar.newTab().setText(tab_name)
                .setTabListener(this));
    }
    /**
     * on swiping the viewpager make respective tab selected
     * */
    viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

        @Override
        public void onPageSelected(int position) {
            // on changing the page
            // make respected tab selected
            actionBar.setSelectedNavigationItem(position);
        }

        @Override
        public void onPageScrolled(int arg0, float arg1, int arg2) {
        }

        @Override
        public void onPageScrollStateChanged(int arg0) {
        }
    });
}

and further down, here is the onClick method that necessitates the refresh...

public void savePars(View view){
    tee.setSlope(Integer.parseInt(((EditText) findViewById(R.id.enter_tee_slope)).getText().toString()));
    tee.setRating(Double.parseDouble(((EditText) findViewById(R.id.enter_tee_rating)).getText().toString()));
    mAdapter.notifyDataSetChanged();
}

Here is the TabsPagerAdapter...

public class TabsPagerAdapter extends FragmentPagerAdapter {
int courseNumber, teeNumber;

public TabsPagerAdapter(FragmentManager fm, int courseNumber, int teeNumber) {
    super(fm);
    this.courseNumber = courseNumber;
    this.teeNumber = teeNumber;
}

@Override
public Fragment getItem(int index) {

    switch (index) {
    case 0:
        // Par Entry activity
        Fragment parFragment = new ParFragment();
        Bundle args = new Bundle();
        args.putInt(ParFragment.ARG_COURSE_NUMBER, courseNumber);
        args.putInt(ParFragment.ARG_TEE_NUMBER, teeNumber);
        parFragment.setArguments(args);
        return parFragment;
    case 1:
        // Handicap Entry fragment activity
        Fragment hcpFragment = new HandicapFragment();
        args = new Bundle();
        args.putInt(HandicapFragment.ARG_COURSE_NUMBER, courseNumber);
        args.putInt(HandicapFragment.ARG_TEE_NUMBER, teeNumber);
        hcpFragment.setArguments(args);
        return hcpFragment;
    }

    return null;
}

@Override
public int getCount() {
    // get item count - equal to number of tabs
    return 2;
}

}

Here is one Fragment...

public class ParFragment extends Fragment {
    public static final String ARG_COURSE_NUMBER = "courseNumber", ARG_TEE_NUMBER = "teeNumber";

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View rootView = inflater.inflate(R.layout.fragment_par, container, false);
        Bundle args = getArguments();
        Course course = Global.getCourse(args.getInt(ARG_COURSE_NUMBER));
        ((TextView) rootView.findViewById(R.id.display_course_name)).setText(course.getName());
        Tee tee = course.getTee(args.getInt(ARG_TEE_NUMBER));
        ((TextView) rootView.findViewById(R.id.display_tee_name)).setText(tee.getTeeName());
        ((TextView) rootView.findViewById(R.id.enter_tee_slope)).setText(Integer.toString(tee.getSlope()));
        ((TextView) rootView.findViewById(R.id.enter_tee_rating)).setText(Double.toString(tee.getRating()));

        return rootView;
    }
}

And here is the other...

public class HandicapFragment extends Fragment {
    public static final String ARG_COURSE_NUMBER = "courseNumber", ARG_TEE_NUMBER = "teeNumber";


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        View rootView = inflater.inflate(R.layout.fragment_handicap, container, false);
        Bundle args = getArguments();
        Course course = Global.getCourse(args.getInt(ARG_COURSE_NUMBER));
        ((TextView) rootView.findViewById(R.id.display_course_name)).setText(course.getName());
        Tee tee = course.getTee(args.getInt(ARG_TEE_NUMBER));
        ((TextView) rootView.findViewById(R.id.display_tee_name)).setText(tee.getTeeName());
        ((TextView) rootView.findViewById(R.id.enter_tee_slope)).setText(Integer.toString(tee.getSlope()));
        ((TextView) rootView.findViewById(R.id.enter_tee_rating)).setText(Double.toString(tee.getRating()));

        return rootView;
    }

}

When the button is clicked, I want to save the values and I want these values to show up on the other fragment.

Help a noob out.

Thanks

Where is your button in fact? In the first fragment or in the second fragment or in the activity? — Son Huy TRAN, Dec 12 '13 at 20:52
Both fragments. In fact both fragments show the data in identical `EditText` views and both fragments have identical button handlers. (there is some fragment-specific data also displayed and entered, but I have left that out of this already too long question.) — ddk, Dec 12 '13 at 21:13

score 2 · Accepted Answer · edited May 23 '17 at 12:30

2

You need to communicate between fragments, but a fragment cannot directly communicate with other fragment, all the communication should be done through the activity which holds these fragments.

The steps to follow are :

Define an Interface in the fragment where you have implemented the onClickListener (let it be Fragment A)
Implement the Interface in the activity which holds these fragments
In the method overridden, retrieve the fragment instance from the viewpager adapter and deliver a message to Fragment B by calling it's public methods.

refer this answer to retrieve fragment instance from adapter

For more details about Communicating with Other Fragments, refer here

edited May 23 '17 at 12:30

Community

1
1

answered Dec 13 '13 at 05:39

Raneez Ahmed

3,808
3
35
58

This gets me so close... but. I pick up the button click in the fragment `ParFragment` and I notify the holding activity. I get to the method in the holding activity that gets notified by the fragment. Now I want to access methods in the 2 tab fragments from the holding activity. `ParFragment parFrag = (ParFragment) getSupportFragmentManager().findFragmentById(R.id.fragment_par);` returns a null value. I define `@+id/fragment_par` in the header of the `fragment_par` xml. How do I get the correct fragment value in order to access the mtehod in the fragment? – ddk Dec 14 '13 at 17:43
I got the final answer from another post. Per @Rafa, `FragmentStatePagerAdapter` does not use tags when adding fragments to the Activity. I used `ParFragment parFrag = (ParFragment) mAdapter.instantiateItem(viewPager, 0)` and it all worked. - Thanks. – ddk Dec 15 '13 at 20:32

score 0 · Answer 2 · answered Dec 12 '13 at 23:34

0

So there is a trick: just let the fragments have the object reference of one another and call the other's function to load data when you handle the onClickListener of the button. E.g:

protected void onClickListener(View view) {
    if (view == myButton) {
        // Do other stuffs here
        fragment1.reloadData();
    }
}

P/S : I re-post this as answer to have the code formatter.

answered Dec 12 '13 at 23:34

Son Huy TRAN

486
2
5
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What do you mean by the "object reference"? How do I get the object reference of the fragment? Do you mean to call the onCreateView, or put the guts of the onCreateView into a method and call that from the fragment OnCreateView and from the onClickListener of the button? – ddk Dec 13 '13 at 01:34
Nope, I meant that: public class Fragment1 extends Fragment { private Fragment2 fragment2; public Fragment2 getFragment2() { return fragment2; } public void setFragment2(Fragment2 fragment2) { this.fragment2 = fragment2; } } So the fragment1 have the reference of fragment2, so that you can call the fragment2's public functions from inside fragment1... And identically for fragment2 which keeps a reference from fragment1... – Son Huy TRAN Dec 13 '13 at 07:46
But where does _fragment2_ ever get a value? If I use your example and try to reference `fragment2.refreshFragment1();`, I get a run-time error because _fragment2_ is never initialized with a pointer to the actual _fragment2_ object and is therefore Null. – ddk Dec 15 '13 at 17:50
But you can check if (fragment1 != null) refreshFragment1();, can't you ? – Son Huy TRAN Dec 16 '13 at 01:18

Refresh Fragment Views based on Button Click

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