CODEWITHSUNDEEP
androidandroid-fragments
Sigma Equties
Sigma Equties

Reputation: 67

Load listview items in fragment from main activity

I am a newbie in android programming.I added three fragments in my main activity as follows.Each fragment contains a list view.The items in list view is added from json output.Now i need to call same json request from each fragments.Can i set listview items from my main activity ? and avoid 2 json requests ?

@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public class MainActivity extends ActionBarActivity implements
        android.support.v7.app.ActionBar.TabListener {
    ViewPager viewPager;

    // Using appcompat action bar
    private android.support.v7.app.ActionBar actionBar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        viewPager = (ViewPager) findViewById(R.id.pager);
        FragmentManager fragmnetManager = getSupportFragmentManager();
        viewPager.setAdapter(new MyAdapter(fragmnetManager));

        viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener()
        {
            @Override
            public void onPageSelected(int pos)
            {
                actionBar.setSelectedNavigationItem(pos);
            }

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

            }

            @Override
            public void onPageScrollStateChanged(int arg0) {

            }
        });

        // Getting actionbar
        actionBar = getSupportActionBar();

        // Setting navigation mode to actionbar
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        // Now adding a new tab to action bar and setting title, icon and
        // implementing listener
        android.support.v7.app.ActionBar.Tab tab1 = actionBar.newTab();
        tab1.setText("TAB1");
        // tab1.setIcon(R.drawable.ic_launcher);
        tab1.setTabListener(this);

        android.support.v7.app.ActionBar.Tab tab2 = actionBar.newTab();
        tab2.setText("TAB2");
        tab2.setTabListener(this);

        android.support.v7.app.ActionBar.Tab tab3 = actionBar.newTab();
        tab3.setText("TAB3");
        tab3.setTabListener(this);

        // Now finally adding all tabs to actionbar
        actionBar.addTab(tab1);
        actionBar.addTab(tab2);
        actionBar.addTab(tab3);

    }

    @Override
    public void onTabReselected(android.support.v7.app.ActionBar.Tab arg0,
                                FragmentTransaction arg1)
    {

    }

    @Override
    public void onTabSelected(android.support.v7.app.ActionBar.Tab tab,
                              FragmentTransaction arg1)
    {

        // Setting current position of tab to view pager
        viewPager.setCurrentItem(tab.getPosition());
    }

    @Override
    public void onTabUnselected(android.support.v7.app.ActionBar.Tab arg0,
                                FragmentTransaction arg1) {

    }

}

// My adapter i.e. custom adapter for displaying fragments over view pager
class MyAdapter extends FragmentPagerAdapter {
    public MyAdapter(FragmentManager fm) {
        super(fm);

    }

    @Override
    public Fragment getItem(int i) {

        // Getting fragments according to selected position
        Fragment fragment = null;
        if (i == 0) {
            fragment = new FragmentA();
        }
        if (i == 1) {
            fragment = new FragmentB();
        }
        if (i == 2) {
            fragment = new FragmentC();
        }

        // and finally returning fragments
        return fragment;
    }

    @Override
    public int getCount() {

        // Returning no. of counts of fragments
        return 3;
    }
}

Upvotes: 0

Views: 1096

Answers (2)

Vikram
Vikram

Reputation: 778

You can also try this if you don't want to implement interface (because you are having only three fragment) - To avoid two json request on different fragment, just send one json request and after getting data in two different list, you can call a method in second fragment to set listview's data in second fragment from first fragment.

Let's say you got two list(firstList, secondList) of data from jsonResponse then set first arraylist in currentFragment and to set data in second fragment try like below method-

Define fragment's instances in Activity like -

FirstFragment firstFragment;
SecondFragment secondFragment;

initialize them where you add fragment like - 

secondFragment = new SecondFragment();

in SecondFragment -

public void updateListView(ArrayList list){
secondArrayList.addAll(list);
secondAdapter = new Adapter(superContext, R.layout.single_item, secondArrayList);
listView.setAdapter(secondAdapter);
}

call this method from activity - 

secondFragment.updateListView(secondList);

This solution is better if you have number of fragments small.

Upvotes: 1

Ragesh Ramesh
Ragesh Ramesh

Reputation: 3520

Yes you can. Create a interface in your mainActivity as follows

     public interface Communicator{
        void onDataLoaded(<Whatever data you want to send to fragment>)
       }

now create an instance of this interface in your main activity

     Communicator mCommunicator;

In your getItem method, for which fragment you want to send data to initialize the communicator as follows

      mCommunicator=(Communicator)fragment;

Then in your main activity once your JSON is loaded just call mCommunicator.onDataLoaded();

Make sure your fragment implements this interface. Once you implement it you will get data there and you can update your listview.

Upvotes: 1

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