Android：轮播图ViewPager自动轮播最简单方法

由于博主学疏才浅，并未了解ViewPager底层逻辑，仅仅将可用的方法加以记录。
最新版的使用轮播图，需要在xml文件中添加

<androidx.viewpager.widget.ViewPager
                android:id="@+id/indicator_all"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                >
            </androidx.viewpager.widget.ViewPager>

之后编写方法

public class shouye extends Fragment {
    View view1,view2,view3,view4;
    private List<View> viewList;
    ViewPager viewPager;
    private Spinner spinner;
    private ArrayAdapter adapter;
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_shouye, container, false);


        viewPager = (ViewPager) view.findViewById(R.id.indicator_all);

        inflater = getLayoutInflater();
        view1 = inflater.inflate(R.layout.layout1, null);
        view2 = inflater.inflate(R.layout.layout2, null);
        view3 = inflater.inflate(R.layout.layout3, null);
        view4 = inflater.inflate(R.layout.layout4, null);


        viewList = new ArrayList<View>();// 将要分页显示的View装入数组中
        viewList.add(view1);
        viewList.add(view2);
        viewList.add(view3);
        viewList.add(view4);


        PagerAdapter pagerAdapter = new PagerAdapter() {

            @Override
            public boolean isViewFromObject(@NonNull View arg0, @NonNull Object arg1) {
                // TODO Auto-generated method stub
                return arg0 == arg1;
            }

            @Override
            public int getCount() {
                // TODO Auto-generated method stub
                return viewList.size();
            }

            @Override
            public void destroyItem(ViewGroup container, int position,
                                    @NonNull Object object) {
                // TODO Auto-generated method stub
                container.removeView(viewList.get(position));
            }

            @NonNull
            @Override
            public Object instantiateItem(ViewGroup container, int position) {
                // TODO Auto-generated method stub
                container.addView(viewList.get(position));


                return viewList.get(position);
            }
        };


        viewPager.setAdapter(pagerAdapter);
        mHandler.sendEmptyMessageDelayed(0, 1000*2);


        return view;
    }

    private Handler mHandler = new Handler() {
        public void handleMessage(Message msg) {
            int count = 4;
            int index=viewPager.getCurrentItem();
            index=(index+1)%count;
            viewPager.setCurrentItem(index);
            mHandler.sendEmptyMessageDelayed(0, 1000*2);
        }
    };
}

图片的自动轮播参考了​​Android之ViewPager自动循环播放（轮播）效果实现（超简单）​​​ 填充的资源文件中放置图片
layout_1

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@drawable/pc1">

    </ImageView>


</LinearLayout>

2022-3-22更
如果需要在轮播图上加导航点，可参考这篇博客
​​​带有导航点的ViewPager​​