无限滚动图像 ViewPager

2022-01-19 00:00:00 android infinite-scroll android-viewpager java

正如 Google 所记录的，Gallery 类在 API 级别 16 中已被弃用.不再支持此小部件.其他水平滚动小部件包括支持库中的 Horizo​​ntalScrollView 和 ViewPager.所以我使用 ViewPager 作为 Gallery 类的替代品.

As documented by Google, the Gallery class was deprecated in API level 16. This widget is no longer supported. Other horizontally scrolling widgets include HorizontalScrollView and ViewPager from the support library. So I used ViewPager as an alternative to the Gallery class.

我的目标是最终实现一个带有文本描述的无限滚动图像 ViewPager.我使用下面的代码来实现带有描述每个图像的文本的图像 ViewPager，但是如何将无限滚动应用到 ViewPager?

My goal to finally achieve an infinite scrolling image ViewPager with text descriptions. I used the below code to achieve the image ViewPager with text describing each image but how do I apply Infinite Scrolling to a ViewPager?

我之前没有使用过 ViewPager，所以请尽可能提供详细的代码.

I have not worked with ViewPager before so please try to provide detailed code if possible.

activity_main.xml:

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

custom_pager.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
   android:layout_width="match_parent" 
   android:layout_height="match_parent" 
   android:orientation="vertical"  
   android:gravity="center_horizontal">
   <ImageView 
       android:id="@+id/myimage" 
       android:layout_width="match_parent" 
       android:layout_height="0dp" 
       android:layout_margin="5dp" 
       android:layout_weight="2" /> 
    <TextView 
       android:id="@+id/image_text" 
       android:layout_width="fill_parent" 
       android:layout_height="0dp"   
       android:layout_weight="1"/>

</LinearLayout>

ImagePager:

public class ImagePager extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ImagePagerAdapter adapter = new ImagePagerAdapter(this, imageArra, stringArray );
        ViewPager myPager = (ViewPager) findViewById(R.id.myimagepager);
        myPager.setAdapter(adapter);
        myPager.setCurrentItem(0);
    }

    private int imageArra[] = { R.drawable.a, R.drawable.b,R.drawable.c, 
                                 R.drawable.d,R.drawable.e,R.drawable.f,
                                 R.drawable.g, R.drawable.h, R.drawable.i};

    private String[] stringArray = new String[] { "Image a", "Image b","Image c"
                                                   "Image d","Image e","Image f", 
                                                   "Image g","Image h","Image i"};


}

ImagePagerAdapter: 

public class ImagePagerAdapter extends PagerAdapter {

    Activity activity;
    int imageArray[];
    String[] stringArray;

    public ImagePagerAdapter(Activity act, int[] imgArra, String[] stringArra) {
        imageArray = imgArra;
        activity = act;
        stringArray = stringArra;
    }

    public int getCount() {
        return imageArray.length;
    }

    public Object instantiateItem(View collection, int position) {
        LayoutInflater inflater = (LayoutInflater)collection.getContext
                          ().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View layout = inflater.inflate(R.layout.custom_pager, null);   

        ImageView im=(ImageView) layout.findViewById(R.id.myimage);             
        im.setImageResource(imageArray[position]);

        TextView txt=(TextView) layout.findViewById(R.id.image_text);
        txt.setText(stringArray[position]);

        ((ViewPager) collection).addView(layout, 0);
          return layout;   
    }

    @Override
    public void destroyItem(View arg0, int arg1, Object arg2) {
        ((ViewPager) arg0).removeView((View) arg2);
    }

    @Override
    public boolean isViewFromObject(View arg0, Object arg1) {
        return arg0 == ((View) arg1);
    }

    @Override
    public Parcelable saveState() {
        return null; 
    }


}

推荐答案

我有 同样的问题，但我找到了解决方法 - 代码可以在 github.

I had the same problem, but I was able to find a way to solve it - the code can be found on github.

如果你复制类 InfiniteViewPager 和 InfinitePagerAdapter 进入你的项目，你可以通过一些小改动实现无限(包裹)滚动.

If you copy the classes InfiniteViewPager and InfinitePagerAdapter into your project, you can achieve infinite (wrapped) scrolling with some small changes.

在您的 Activity 中，使用 InfinitePagerAdapter 包装 PagerAdapter:

In your Activity, wrap your PagerAdapter with an InfinitePagerAdapter:

PagerAdapter adapter = new InfinitePagerAdapter(new ImagePagerAdapter(this, imageArra, stringArray));

将活动 XML 中的 ViewPager 更改为 InfiniteViewPager:

Change the ViewPager in the activity XML to be an InfiniteViewPager:

<com.antonyt.infiniteviewpager.InfiniteViewPager 
       android:id="@+id/myimagepager" 
       android:layout_width="match_parent" 
       android:layout_height="match_parent" />

您可以将类重命名为您想要的任何名称.此代码仅在您至少有三页时才有效(示例代码中有九页，因此它可以正常工作).

You can rename the classes to whatever you want. This code only works if you have at least three pages (you have nine in your example code, so it will work fine for that).

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