ViewPagerExtensionsで簡単に左右スライドのタブを作る

ViewPagerExtensionsというライブラリーを使ってAndroid 4.xの連絡先アプリのように左右スライドできるタブを簡単に作る方法を紹介します。



ライブラリーはこちらからダウンロードできます。
ViewPagerExtensions
https://github.com/astuetz/ViewPagerExtensions

Adapterを用意する
MyTabAdapter.java

public class MyTabAdapter extends PagerAdapter implements TabsAdapter {

    private Activity mActivity;
    private List mView;
    private String[] mTitles;

    public MyTabAdapter (Activity activity, List<View> view) {
        this.mActivity = activity;
        this.mView = view;
    }

    public void setTitleArr(String[] title) {
        this.mTitles = title;
    }

    @Override
    public int getCount() {
        return mView.size();
    }

    @Override
    public View getView(int position) {
        Button tab;
        LayoutInflater inflater = mActivity.getLayoutInflater();
        tab = (Button) inflater.inflate(R.layout.tab_scrolling, null);
        
        if (position < mTitles.length) tab.setText(mTitles[position]);
        
        return tab;
    }

    @Override
    public Object instantiateItem( View pager, int position ) {
        ViewGroup parent = (ViewGroup)mView.get(position).getParent();
        if (parent != null) {
            parent.removeView(mView.get(position));
        }
        View view = mView.get(position);
        ((ViewPager)pager).addView(view, 0);
        return view;
    }

    @Override
    public void destroyItem( View pager, int position, Object view ) {
        ( (ViewPager) pager ).removeView( (View) view );
    }

    @Override
    public boolean isViewFromObject( View view, Object object ) {
        return view.equals( object );
    }
 
    @Override
    public void finishUpdate( View view ) {}
 
    @Override
    public void restoreState( Parcelable p, ClassLoader c ) {}
 
    @Override
    public Parcelable saveState() {
        return null;
    }
 
    @Override
    public void startUpdate( View view ) {}
}

Viewのレイアウトを用意する
/res/layout/pager_view.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#000"
    android:gravity="center_vertical"
    android:orientation="vertical"
    >
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingTop="5dp"
        android:layout_gravity="center"
        android:textColor="#666666"
        android:textSize="15sp"
        android:id="@+id/textview"
        />
</LinearLayout>

res/layout/activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    tools:context=".MainActivity" >
    <com.astuetz.viewpager.extensions.ScrollingTabsView
        android:id="@+id/scrolling_tabs"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        />
    <android.support.v4.view.ViewPager
        android:id="@+id/pager"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_below="@+id/scrolling_tabs"
        />
</RelativeLayout>

PagerとTabアダブターの設定
MainActivity.java

public class MainActivity extends Activity {

    private LayoutInflater layoutInflater;
    private List<View> arrView;
    private MyTabAdapter adapter;

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

        arrView = new ArrayList<View>();
        layoutInflater = this.getLayoutInflater();
        int tabNum = 5;
        String[] titles = new String[tabNum];

        View viewPage;
        for (int i = 0; i<tabNum; i++) {
            String tabText = "Tab" + String.valueOf(i + 1);
            titles[i] = tabText;
            viewPage = layoutInflater.inflate(R.layout.pager_view, null);
            ((TextView)viewPage.findViewById(R.id.textview))
                .setText("This is " + tabText);
            arrView.add(viewPage);
        }

        adapter = new MyTabAdapter(this, arrView);
        adapter.setTitleArr(titles);

        ViewPager pager = (ViewPager)findViewById(R.id.pager);
        ScrollingTabsView scrollingTabs = (ScrollingTabsView)findViewById(R.id.scrolling_tabs);
        pager.setAdapter(adapter);
        pager.setCurrentItem(0);
        pager.setPageMargin(1);

        scrollingTabs.setAdapter(adapter);
        scrollingTabs.setViewPager(pager);
    }
}

実行イメージ


R.layout.tab_scrollingのレイアウトでタブのデザインを変更できます。以上のようなタブUIは以下のサンプルから参考しました。
https://github.com/astuetz/ViewPagerExtensions/downloads