android-Implementing Effective Navigation,Creating Swipe Views with Tabs

 After reading the lessons in this class, you should have a strong understanding of how to implement navigation patterns with tabs, swipe views, and a navigation drawer. You should also understand how to provide proper Up and Back navigation.

 Swipe views provide lateral navigation between sibling screens such as tabs with a horizontal finger gesture (a pattern sometimes known as horizontal paging). 

 > You can create swipe views in your app using the ViewPagerwidget, available in the Support Library. The ViewPager is a layout widget in which each child view is a separate page (a separate tab) in the layout.

 To insert child views that represent each page, you need to hook this layout to a PagerAdapter. There are two kinds of adapter you can use:

FragmentPagerAdapter

This is best when navigating between sibling screens representing a fixed, small number of pages.

FragmentStatePagerAdapter

This is best for paging across a collection of objects for which the number of pages is undetermined. It destroys fragments as the user navigates to other pages, minimizing memory usage.

public class CollectionDemoActivity extends FragmentActivity {
    // When requested, this adapter returns a DemoObjectFragment,
    // representing an object in the collection.
    DemoCollectionPagerAdapter mDemoCollectionPagerAdapter;
    ViewPager mViewPager;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_collection_demo);

        // ViewPager and its adapters use support library
        // fragments, so use getSupportFragmentManager.
        mDemoCollectionPagerAdapter =
                new DemoCollectionPagerAdapter(
                        getSupportFragmentManager());
        mViewPager = (ViewPager) findViewById(R.id.pager);
        mViewPager.setAdapter(mDemoCollectionPagerAdapter);
    }
}

// Since this is an object collection, use a FragmentStatePagerAdapter,
// and NOT a FragmentPagerAdapter.
public class DemoCollectionPagerAdapter extends FragmentStatePagerAdapter {
    public DemoCollectionPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int i) {
        Fragment fragment = new DemoObjectFragment();
        Bundle args = new Bundle();
        // Our object is just an integer :-P
        args.putInt(DemoObjectFragment.ARG_OBJECT, i + 1);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public int getCount() {
        return 100;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return "OBJECT " + (position + 1);
    }
}

// Instances of this class are fragments representing a single
// object in our collection.
public static class DemoObjectFragment extends Fragment {
    public static final String ARG_OBJECT = "object";

    @Override
    public View onCreateView(LayoutInflater inflater,
            ViewGroup container, Bundle savedInstanceState) {
        // The last two arguments ensure LayoutParams are inflated
        // properly.
        View rootView = inflater.inflate(
                R.layout.fragment_collection_object, container, false);
        Bundle args = getArguments();
        ((TextView) rootView.findViewById(android.R.id.text1)).setText(
                Integer.toString(args.getInt(ARG_OBJECT)));
        return rootView;
    }
}

 Action bar tabs offer users a familiar interface for navigating between and identifying sibling screens in your app.

 To create tabs using ActionBar, you need to enable NAVIGATION_MODE_TABS, then create several instances ofActionBar.Tab and supply an implementation of the ActionBar.TabListener interface for each one. For example, in your activity's onCreate() method, you can use code similar to this:

@Override
public void onCreate(Bundle savedInstanceState) {
    final ActionBar actionBar = getActionBar();
    ...

    // Specify that tabs should be displayed in the action bar.
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Create a tab listener that is called when the user changes tabs.
    ActionBar.TabListener tabListener = new ActionBar.TabListener() {
        public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
            // show the given tab
        }

        public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
            // hide the given tab
        }

        public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
            // probably ignore this event
        }
    };

    // Add 3 tabs, specifying the tab's text and TabListener
    for (int i = 0; i < 3; i++) {
        actionBar.addTab(
                actionBar.newTab()
                        .setText("Tab " + (i + 1))
                        .setTabListener(tabListener));
    }
}

// Create a tab listener that is called when the user changes tabs.
    ActionBar.TabListener tabListener = new ActionBar.TabListener() {
        public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
            // When the tab is selected, switch to the
            // corresponding page in the ViewPager.
            mViewPager.setCurrentItem(tab.getPosition());
        }

mViewPager = (ViewPager) findViewById(R.id.pager);
    mViewPager.setOnPageChangeListener(
            new ViewPager.SimpleOnPageChangeListener() {
                @Override
                public void onPageSelected(int position) {
                    // When swiping between pages, select the
                    // corresponding tab.
                    getActionBar().setSelectedNavigationItem(position);
                }
            });

Below is an example layout XML file for an activity whose entire contents are a ViewPager and a top-alignedPagerTitleStrip inside it. Individual pages (provided by the adapter) occupy the remaining space inside theViewPager.

<android.support.v4.view.ViewPager
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v4.view.PagerTitleStrip
        android:id="@+id/pager_title_strip"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="top"
        android:background="#33b5e5"
        android:textColor="#fff"
        android:paddingTop="4dp"
        android:paddingBottom="4dp" />

</android.support.v4.view.ViewPager>