My previous article explains about Android Tab Layoutand it got very good ranking in search engines. But unfortunately TabHost is deprecated by android in favor of fragments. So it is suggested that use fragment to achieve tab layout.
This article shows you how to create tab layout using fragments and viewpager. Also you can swipe between tab view as it is the functionality of viewpager which is not possible when using TabHost.
ViewPager and Fragments
Before getting into this tutorial it is suggested to have knowledge on Fragments and ViewPager as these two are main concepts used here. Unfortunately I haven’t covered about fragements and viewpager on androidhive 
Layout Overview
Checkout the following pic which explains the complete overview of layout architecture. Basically we are using ViewPager as main layout and for individual pager views we use Fragments. The tabs are part of Action Bar.
Creating new Project
Even though you are not familiar with ViewPager or Fragments, don’t worry. You will get an idea about what those are and how to use them once you are done through this article. So let’s start by creating a new project.
1. Create a new project in Eclipse from File ⇒ New ⇒ Android ⇒ Application Project. While creating the project select the app theme which has Action Bar as shown in the below image.
2. As we are going to use Fragments, extend your main activity from FragmentActivity. Alsoimplement this class from ActionBar.TabListener as we are adding Tabs too.
public class MainActivity extends FragmentActivity implements ActionBar.TabListener { |
3. Open main activity layout file and add ViewPager element. (My layout file for main activity isactivity_main.xml)
android:id="@+id/pager" android:layout_width="match_parent" android:layout_height="match_parent"></android.support.v4.view.ViewPager> |
4. I normally prefer to create a separate package for adapter classes just to separate them from activity classes. So create a new package named your_package_name.adapter. I named my new package asinfo.androidhive.tabsswipe.adapter
5. I am creating a FragmentPagerAdapter class to provide views to tab fragments. Create a class called TabsPagerAdapter.java under adapter package. This adapter provides fragment views to tabs which we are going to create them later in this tutorial.
package info.androidhive.tabsswipe.adapter;import info.androidhive.tabsswipe.GamesFragment;import info.androidhive.tabsswipe.MoviesFragment;import info.androidhive.tabsswipe.TopRatedFragment;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentPagerAdapter;public class TabsPagerAdapter extends FragmentPagerAdapter { public TabsPagerAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int index) { switch (index) { case 0: // Top Rated fragment activity return new TopRatedFragment(); case 1: // Games fragment activity return new GamesFragment(); case 2: // Movies fragment activity return new MoviesFragment(); } return null; } @Override public int getCount() { // get item count - equal to number of tabs return 3; }} |
Adding Tabs to Action Bar
6. In order to display tabs we don’t have to use any other UI element like TabHost. Action bar has the inbuilt capability of adding tabs. All we have to do is enable it usingsetNavigationMode(ActionBar.NAVIGATION_MODE_TABS) method. Open your MainActivity.javado the following.
Here I am adding three tabs Top Rated, Games, Movies to action bar. So I just stored all the tab names in a String array and added them to action bar using a for loop.
public class MainActivity extends FragmentActivity implements ActionBar.TabListener { private ViewPager viewPager; private TabsPagerAdapter mAdapter; private ActionBar actionBar; // Tab titles private String[] tabs = { "Top Rated", "Games", "Movies" }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // Initilization viewPager = (ViewPager) findViewById(R.id.pager); actionBar = getActionBar(); mAdapter = new TabsPagerAdapter(getSupportFragmentManager()); 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)); } |
If you run the project, you can see the tabs displaying under action bar.
Adding Views for Tabs
We already returned respected fragments for tabs in the adapter class. To make it simple I am creating very simple layout for each tab and leaving it to you to build your own UI depending on your requirement. For now I just displayed a label in the view with some background color.
» First Tab View
7. The first tab I added is Top Rated. Create a new layout file under src ⇒ res folder namedfragment_top_rated.xml and paste the following code.
<?xml version="1.0" encoding="utf-8"?> android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:background="#fa6a6a" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center" android:text="Design Top Rated Screen" android:textSize="20dp" android:layout_centerInParent="true"/> </RelativeLayout> |
8. Also create respected Fragment activity class for this view. Create a new class namedTopRatedFragment.java under your main package.
package info.androidhive.tabsswipe;import info.androidhive.tabsswipe.R;import android.os.Bundle;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;public class TopRatedFragment extends Fragment { @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_top_rated, container, false); return rootView; }} |
» Second Tab View
The second tab in the list is Games. Just like above create a layout file and activity file for this tab.
9. Create a new layout file under src ⇒ res folder named fragment_games.xml
<?xml version="1.0" encoding="utf-8"?> android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:background="#ff8400" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center" android:text="Design Games Screen" android:textSize="20dp" android:layout_centerInParent="true"/> </RelativeLayout> |
10. Create a new class named GamesFragment.java with following code.
package info.androidhive.tabsswipe;import info.androidhive.tabsswipe.R;import android.os.Bundle;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;public class GamesFragment extends Fragment { @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_games, container, false); return rootView; }} |
» Third Tab View
This third tab is Movies. This one need a layout file and activity class.
11. Create a layout file called fragment_movies.xml
<?xml version="1.0" encoding="utf-8"?> android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:background="#17df0d"> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center" android:text="Design Movies Screen" android:textSize="20dp" android:layout_centerInParent="true"/> </RelativeLayout> |
12. Also create activity class for this view named MoviesFragment.java
package info.androidhive.tabsswipe;import info.androidhive.tabsswipe.R;import android.os.Bundle;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;public class MoviesFragment extends Fragment { @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_movies, container, false); return rootView; }} |
Run the project and check whether the views for tabs are added or not.
And this is how it looks in landscape mode
Tab Change Listener
If you run the project you can see the swiping views working, but if you select a tab, view won’t change automatically. This is because ViewPager didn’t know about the tab change event. We have to manually change the view using Tab change listener.
13. In your MainActivity.java class add following code.
@Override public void onTabReselected(Tab tab, FragmentTransaction ft) { } @Override public void onTabSelected(Tab tab, FragmentTransaction ft) { // on tab selected // show respected fragment view viewPager.setCurrentItem(tab.getPosition()); } @Override public void onTabUnselected(Tab tab, FragmentTransaction ft) { } |
View Change Listener
14. As well if you swipe the view, you can’t see respected tab selected. Here also using ViewPagersetOnPageChangeListener() we have to select the respected tab manually.
/** * 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) { }}); |
After adding these two listeners, if you run the project you can see everything working good.
Complete Code
Below is the complete code for MainActivity.java class
package info.androidhive.tabsswipe;import info.androidhive.tabsswipe.adapter.TabsPagerAdapter;import info.androidhive.tabsswipe.R;import android.app.ActionBar;import android.app.ActionBar.Tab;import android.app.FragmentTransaction;import android.os.Bundle;import android.support.v4.app.FragmentActivity;import android.support.v4.view.ViewPager;import android.view.Menu;public class MainActivity extends FragmentActivity implements ActionBar.TabListener { private ViewPager viewPager; private TabsPagerAdapter mAdapter; private ActionBar actionBar; // Tab titles private String[] tabs = { "Top Rated", "Games", "Movies" }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // Initilization viewPager = (ViewPager) findViewById(R.id.pager); actionBar = getActionBar(); mAdapter = new TabsPagerAdapter(getSupportFragmentManager()); 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) { } }); } @Override public void onTabReselected(Tab tab, FragmentTransaction ft) { } @Override public void onTabSelected(Tab tab, FragmentTransaction ft) { // on tab selected // show respected fragment view viewPager.setCurrentItem(tab.getPosition()); } @Override public void onTabUnselected(Tab tab, FragmentTransaction ft) { }} |
谢嘉琪 