Android Studio Master/Detail Flow Template

ItemDetailActivity.java

package com.natebass.thefrag2;

import android.content.Intent;
import android.os.Bundle;
import android.app.Activity;

import android.view.MenuItem;


/**
 * An activity representing a single Item detail screen. This
 * activity is only used on handset devices. On tablet-size devices,
 * item details are presented side-by-side with a list of items
 * in a {@link ItemListActivity}.
 * <p/>
 * This activity is mostly just a 'shell' activity containing nothing
 * more than a {@link ItemDetailFragment}.
 */
public class ItemDetailActivity extends Activity {

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

        // Show the Up button in the action bar.
        getActionBar().setDisplayHomeAsUpEnabled(true);

        // savedInstanceState is non-null when there is fragment state
        // saved from previous configurations of this activity
        // (e.g. when rotating the screen from portrait to landscape).
        // In this case, the fragment will automatically be re-added
        // to its container so we don't need to manually add it.
        // For more information, see the Fragments API guide at:
        //
        // http://developer.android.com/guide/components/fragments.html
        //
        if (savedInstanceState == null) {
            // Create the detail fragment and add it to the activity
            // using a fragment transaction.
            Bundle arguments = new Bundle();
            arguments.putString(ItemDetailFragment.ARG_ITEM_ID,
                    getIntent().getStringExtra(ItemDetailFragment.ARG_ITEM_ID));
            ItemDetailFragment fragment = new ItemDetailFragment();
            fragment.setArguments(arguments);
            getFragmentManager().beginTransaction()
                    .add(R.id.item_detail_container, fragment)
                    .commit();
        }
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == android.R.id.home) {
            // This ID represents the Home or Up button. In the case of this
            // activity, the Up button is shown. For
            // more details, see the Navigation pattern on Android Design:
            //
            // http://developer.android.com/design/patterns/navigation.html#up-vs-back
            //
            navigateUpTo(new Intent(this, ItemListActivity.class));
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

ItemDetailFragment.java

package com.natebass.thefrag2;

import android.os.Bundle;
import android.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;


import com.natebass.thefrag2.dummy.DummyContent;

/**
 * A fragment representing a single Item detail screen.
 * This fragment is either contained in a {@link ItemListActivity}
 * in two-pane mode (on tablets) or a {@link ItemDetailActivity}
 * on handsets.
 */
public class ItemDetailFragment extends Fragment {
    /**
     * The fragment argument representing the item ID that this fragment
     * represents.
     */
    public static final String ARG_ITEM_ID = "item_id";

    /**
     * The dummy content this fragment is presenting.
     */
    private DummyContent.DummyItem mItem;

    /**
     * Mandatory empty constructor for the fragment manager to instantiate the
     * fragment (e.g. upon screen orientation changes).
     */
    public ItemDetailFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (getArguments().containsKey(ARG_ITEM_ID)) {
            // Load the dummy content specified by the fragment
            // arguments. In a real-world scenario, use a Loader
            // to load content from a content provider.
            mItem = DummyContent.ITEM_MAP.get(getArguments().getString(ARG_ITEM_ID));
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_item_detail, container, false);

        // Show the dummy content as text in a TextView.
        if (mItem != null) {
            ((TextView) rootView.findViewById(R.id.item_detail)).setText(mItem.content);
        }

        return rootView;
    }
}

ItemListActivity.java

package com.natebass.thefrag2;

import android.content.Intent;
import android.os.Bundle;
import android.app.Activity;


/**
 * An activity representing a list of Items. This activity
 * has different presentations for handset and tablet-size devices. On
 * handsets, the activity presents a list of items, which when touched,
 * lead to a {@link ItemDetailActivity} representing
 * item details. On tablets, the activity presents the list of items and
 * item details side-by-side using two vertical panes.
 * <p/>
 * The activity makes heavy use of fragments. The list of items is a
 * {@link ItemListFragment} and the item details
 * (if present) is a {@link ItemDetailFragment}.
 * <p/>
 * This activity also implements the required
 * {@link ItemListFragment.Callbacks} interface
 * to listen for item selections.
 */
public class ItemListActivity extends Activity
        implements ItemListFragment.Callbacks {

    /**
     * Whether or not the activity is in two-pane mode, i.e. running on a tablet
     * device.
     */
    private boolean mTwoPane;

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

        if (findViewById(R.id.item_detail_container) != null) {
            // The detail container view will be present only in the
            // large-screen layouts (res/values-large and
            // res/values-sw600dp). If this view is present, then the
            // activity should be in two-pane mode.
            mTwoPane = true;

            // In two-pane mode, list items should be given the
            // 'activated' state when touched.
            ((ItemListFragment) getFragmentManager()
                    .findFragmentById(R.id.item_list))
                    .setActivateOnItemClick(true);
        }

        // TODO: If exposing deep links into your app, handle intents here.
    }

    /**
     * Callback method from {@link ItemListFragment.Callbacks}
     * indicating that the item with the given ID was selected.
     */
    @Override
    public void onItemSelected(String id) {
        if (mTwoPane) {
            // In two-pane mode, show the detail view in this activity by
            // adding or replacing the detail fragment using a
            // fragment transaction.
            Bundle arguments = new Bundle();
            arguments.putString(ItemDetailFragment.ARG_ITEM_ID, id);
            ItemDetailFragment fragment = new ItemDetailFragment();
            fragment.setArguments(arguments);
            getFragmentManager().beginTransaction()
                    .replace(R.id.item_detail_container, fragment)
                    .commit();

        } else {
            // In single-pane mode, simply start the detail activity
            // for the selected item ID.
            Intent detailIntent = new Intent(this, ItemDetailActivity.class);
            detailIntent.putExtra(ItemDetailFragment.ARG_ITEM_ID, id);
            startActivity(detailIntent);
        }
    }
}

ItemListFragment.java

package com.natebass.thefrag2;

import android.app.Activity;
import android.os.Bundle;
import android.app.ListFragment;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;


import com.natebass.thefrag2.dummy.DummyContent;

/**
 * A list fragment representing a list of Items. This fragment
 * also supports tablet devices by allowing list items to be given an
 * 'activated' state upon selection. This helps indicate which item is
 * currently being viewed in a {@link ItemDetailFragment}.
 * <p/>
 * Activities containing this fragment MUST implement the {@link Callbacks}
 * interface.
 */
public class ItemListFragment extends ListFragment {

    /**
     * The serialization (saved instance state) Bundle key representing the
     * activated item position. Only used on tablets.
     */
    private static final String STATE_ACTIVATED_POSITION = "activated_position";

    /**
     * The fragment's current callback object, which is notified of list item
     * clicks.
     */
    private Callbacks mCallbacks = sDummyCallbacks;

    /**
     * The current activated item position. Only used on tablets.
     */
    private int mActivatedPosition = ListView.INVALID_POSITION;

    /**
     * A callback interface that all activities containing this fragment must
     * implement. This mechanism allows activities to be notified of item
     * selections.
     */
    public interface Callbacks {
        /**
         * Callback for when an item has been selected.
         */
        public void onItemSelected(String id);
    }

    /**
     * A dummy implementation of the {@link Callbacks} interface that does
     * nothing. Used only when this fragment is not attached to an activity.
     */
    private static Callbacks sDummyCallbacks = new Callbacks() {
        @Override
        public void onItemSelected(String id) {
        }
    };

    /**
     * Mandatory empty constructor for the fragment manager to instantiate the
     * fragment (e.g. upon screen orientation changes).
     */
    public ItemListFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // TODO: replace with a real list adapter.
        setListAdapter(new ArrayAdapter<DummyContent.DummyItem>(
                getActivity(),
                android.R.layout.simple_list_item_activated_1,
                android.R.id.text1,
                DummyContent.ITEMS));
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        // Restore the previously serialized activated item position.
        if (savedInstanceState != null
                && savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) {
            setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION));
        }
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        // Activities containing this fragment must implement its callbacks.
        if (!(activity instanceof Callbacks)) {
            throw new IllegalStateException("Activity must implement fragment's callbacks.");
        }

        mCallbacks = (Callbacks) activity;
    }

    @Override
    public void onDetach() {
        super.onDetach();

        // Reset the active callbacks interface to the dummy implementation.
        mCallbacks = sDummyCallbacks;
    }

    @Override
    public void onListItemClick(ListView listView, View view, int position, long id) {
        super.onListItemClick(listView, view, position, id);

        // Notify the active callbacks interface (the activity, if the
        // fragment is attached to one) that an item has been selected.
        mCallbacks.onItemSelected(DummyContent.ITEMS.get(position).id);
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        if (mActivatedPosition != ListView.INVALID_POSITION) {
            // Serialize and persist the activated item position.
            outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition);
        }
    }

    /**
     * Turns on activate-on-click mode. When this mode is on, list items will be
     * given the 'activated' state when touched.
     */
    public void setActivateOnItemClick(boolean activateOnItemClick) {
        // When setting CHOICE_MODE_SINGLE, ListView will automatically
        // give items the 'activated' state when touched.
        getListView().setChoiceMode(activateOnItemClick
                ? ListView.CHOICE_MODE_SINGLE
                : ListView.CHOICE_MODE_NONE);
    }

    private void setActivatedPosition(int position) {
        if (position == ListView.INVALID_POSITION) {
            getListView().setItemChecked(mActivatedPosition, false);
        } else {
            getListView().setItemChecked(position, true);
        }

        mActivatedPosition = position;
    }
}

Hols Luis