Receive onclick value from Android Library via Page Fragment

Question

Currently I have Project A (as Android Library) and Project B.

In Project B I am using page fragment for the design. At page fragment 1, the fragment is actually called from Project A (the library).

How do i receive the onclick value on Project A to Project B.

// Declare the fragment page on Project B

CustFragment fragment1 = new CustFragment ();

// onclick listener on Project A

mContactList.setOnItemClickListener(new OnItemClickListener() {

        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {

            Cursor cursor = (Cursor) parent.getAdapter().getItem(position);

            long rawId = cursor.getLong(cursor
                    .getColumnIndex(ContactsContract.Data.RAW_CONTACT_ID));

// how do i pass the value to B?

EDITED: I edited this post with more code from my side

// Declare the fragment on Project B

public class MainPagerFragmentAdapter extends FragmentPagerAdapter {

ListFragment list;
SearchFragment search;  
public MainPagerFragmentAdapter(FragmentManager fragmentManager) {
    super(fragmentManager);
}

@Override
public int getCount() {
    return 2;
}

public String getPageTitle(int position) {
    switch (position) {
        case 0: return AppSingleton.getCurrentActivity().getString(R.string.pager_appointments_tab);
        case 1: return  AppSingleton.getCurrentActivity().getString(R.string.explist_filter_text);
    }
}

@Override
public Fragment getItem(int position) {

    switch (position) {             
        case 0:
            if (customerList == null)
                list = new ListFragment();
            return customerList;
        case 1:
            if (contactSearch == null)
                search = new SearchFragment();
            return contactSearch;
    }

    return null;
}

}

// onclick listener on Project A (library project)

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

    super.onCreateView(inflater, container, savedInstanceState);
    log.info("ContactsFragment onCreateView");
    mContactFragmentView = inflater.inflate(R.layout.fragment_contacts,
            container, false);

    mContactList = (ListView) mContactFragmentView
            .findViewById(R.id.contacts_list);

    mContactList.setOnItemClickListener(new OnItemClickListener() {

        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {

            Cursor cursor = (Cursor) parent.getAdapter().getItem(position);

            long rawId = cursor.getLong(cursor
                    .getColumnIndex(ContactsContract.Data.RAW_CONTACT_ID));

            // what have to done here to pass back to B dynamically

        }

    });
    getLoaderManager().initLoader(0, null, this);
    return mContactFragmentView;
}

java.lang.NullPointerException at com.contact.library.ContactsFragment$2.onItemClick(ContactsFragment.java:143) at android.widget.AdapterView.performItemClick(AdapterView.java:308) at android.widget.AbsListView.performItemClick(AbsListView.java:1509) at android.widget.AbsListView$PerformClick.run(AbsListView.java:3467) at android.widget.AbsListView$3.run(AbsListView.java:4830) at android.os.Handler.handleCallback(Handler.java:733) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:146) at android.app.ActivityThread.main(ActivityThread.java:5602) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099) at dalvik.system.NativeStart.main(Native Method)

josephus josephus · Accepted Answer · 2014-08-15T02:47:15

You want to set up a callback triggered on Fragment A. Similar to this:

create an interface in your library:

public interface MyInterface {
  public void onRawIdAcquired(long rawId);
}

Create an instance of it somewhere in your FragmentA (and make a setter that can set its value):

public class FragmentA extends Fragment {
...
MyInterface i;
...
public void setListener(MyInterface i) {
  this.i = i;
}

then call it when rowId gets the value:

long rawId = cursor.getLong(cursor.getColumnIndex(ContactsContract.Data.RAW_CONTACT_ID));
i.onRawIdAcquired(rawId);

Now in your PageFragment in your non-library activty, implement MyInterface and override onRawIdAcquired:

public PageFragment extends Fragment implements MyInterface {
@Override
public void onRawIdAcquired(long rawId) {
  **// you can now use the value of rawId here.**
}

Finally, somewhere when instantiating your FragmentA, pass PageFragment in setListener:

FragmentA f = ...;
PageFragment myPageFragment = ...;
f.setListener(myPageFragment);

Receive onclick value from Android Library via Page Fragment

2 Answers