ViewPager引導頁

ViewPager引導頁

viewPager引導頁能夠方便的實現頁面的左右滑動的切換，能夠做爲應用程序的引導頁，也能夠做爲整個應用程序的框架。

首先建立引導頁的首頁：

public class MainActivity extends AppCompatActivity {
  private ViewPager viewPager ;  //
  private ViewPageAdapter viewPageAdapter ;
  private List<View> views ;   //View集合，左右滑動的實際上是一個View的集合
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      initViews();

  }
  private void initViews(){
      LayoutInflater inflater = LayoutInflater.from(this);

      views = new ArrayList<>();
      //加添View的view。
      views.add(inflater.inflate(R.layout.one,null));
      views.add(inflater.inflate(R.layout.two,null));
      views.add(inflater.inflate(R.layout.three,null));

      //爲ViewPager添加適配器
      ViewPageAdapter adapter = new ViewPageAdapter(views,this);
      viewPager = (ViewPager) findViewById(R.id.viewpager);
      viewPager.setAdapter(adapter);
  }
}

ViewPager 的適配器類

public class ViewPageAdapter extends PagerAdapter {
    private List<View> views ;
    private Context context ;

    public ViewPageAdapter(List<View> views, Context context) {
        this.views = views;
        this.context = context;
    }
    //返回Views的條目總數
    @Override
    public int getCount() {
        if (views!=null){
            return views.size();
        }
        return  0 ;
    }

    //刪除頁面
    @Override
    public void destroyItem(View container, int position, Object object) {
        ((ViewPager) container).removeView(views.get(position));

    }

    //初始化界面
    @Override
    public Object instantiateItem(View arg0, int position) {

        ((ViewPager) arg0).addView(views.get(position), 0);

        return views.get(position);
    }
   //判斷是不是須要的View對象
    @Override
    public boolean isViewFromObject(View view, Object object) {
        return (view==object);
    }
}

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.it123.pageadapter.MainActivity">
    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#fff">

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

</RelativeLayout>

one.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imageView"
        android:src="@mipmap/ic_launcher"
        android:layout_gravity="center_horizontal" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="第一頁"
        android:id="@+id/textView"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true" />
</RelativeLayout>

two.xml 和 three.xml 的代碼和one.xml 的代碼一致。不在重複。 運行便可實現左右滑動切換的效果