viewpage启动页

<androidx.constraintlayout.widget.ConstraintLayout 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"
    tools:context=".MainActivity">

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

    <LinearLayout
        android:id="@+id/viewpager_tag_viewgroup"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="32dp"
        android:gravity="center_horizontal"
        android:orientation="horizontal"
android:layout_marginRight="60px"
        android:padding="20dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"></LinearLayout>

    <Button
        android:id="@+id/view_pager_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@id/viewpager_tag_viewgroup"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="128dp"
        android:background="@drawable/shap3"

        android:text="立即体验"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

public class MainActivity extends Activity implements ViewPager.OnPageChangeListener {

        private ViewPager mViewPager;
        //图片资源的数组
        private int[] mImageIdArray;
        //图片的集合
        private List<View> mViewList;
        //放置圆点
        private ViewGroup mViewGroup;
        //实例化圆点View
        private ImageView mImageView;
        private ImageView[] mImageViewArray;
        //最后一页的按钮
        private Button mButton;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            requestWindowFeature(Window.FEATURE_NO_TITLE);
            getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                    WindowManager.LayoutParams.FLAG_FULLSCREEN);

            setContentView(R.layout.activity_main);

            mButton = (Button) findViewById(R.id.view_pager_button);
            mButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
//                    startActivity(new Intent(ViewPagerActivity.this, LoginActivity.class));
//                    finish();
                }
            });
            //加载ViewPager
            initViewpager();
            //加载底部圆点
            initViewPagerTag();

        }

        /**
         * 加载底部圆点
         */
        private void initViewPagerTag() {
            //这里实例化LinearLayout
            mViewGroup = (ViewGroup) findViewById(R.id.viewpager_tag_viewgroup);
            //根据ViewPager的item数量实例化数组
            mImageViewArray = new ImageView[mViewList.size()];
            //循环新建底部圆点imageview，将生成的imageview保存到数组中
            for (int i = 0; i < mViewList.size(); i++) {
                mImageView = new ImageView(this);
                LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(20, 20);
                layoutParams.leftMargin = 60;
                mImageView.setLayoutParams(layoutParams);

                mImageViewArray[i] = mImageView;
                //第一个页面需要设为选中状态，这里要使用两张不同的图片（选中与未选中）
                if (i == 0) {
                    mImageView.setBackgroundResource(R.drawable.shap1);
                } else {
                    mImageView.setBackgroundResource(R.drawable.shap2);
                }
                //将数组中的imageview加入到viewgroup
                mViewGroup.addView(mImageViewArray[i]);
            }
        }

        /**
         * 加载ViewPager
         */
        private void initViewpager() {
            mViewPager = (ViewPager) findViewById(R.id.first_viewpager);
            //实例化图片资源
            mImageIdArray = new int[]{R.drawable.lunch1, R.drawable.lunch2, R.drawable.lunch3, R.drawable.lunch4};

            mViewList = new ArrayList<View>();
            //获取一个layout参数，设置为match_parent
            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT
                    , LinearLayout.LayoutParams.MATCH_PARENT);

            //循环创建view并进入集合
            for (int i = 0; i < mImageIdArray.length; i++) {
                //new imageview并设置全屏和图片资源
                ImageView imageView = new ImageView(this);
                imageView.setLayoutParams(params);
                imageView.setBackgroundResource(mImageIdArray[i]);

                //将imageview加入到View集合中
                mViewList.add(imageView);
            }
            //View集合数据初始化好，setAdapter就可以了
            mViewPager.setAdapter(new GuidePagerAdapter(mViewList));
            //添加ViewPager的滑动监听，注意是.add...以前是setOnPageChangeListener方法，已过时
            mViewPager.addOnPageChangeListener(this);
        }

        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

        }
        //滑动后的监听
        @Override
        public void onPageSelected(int position) {
            //循环设置当前页的标记图
            for (int i = 0; i < mImageViewArray.length; i++) {
                mImageViewArray[position].setBackgroundResource(R.drawable.shap1);
                if (position != i) {
                    mImageViewArray[i].setBackgroundResource(R.drawable.shap2);
                }
            }
            //判断是否最后一页，是则显示button
            if (position == mImageViewArray.length - 1) {
                mButton.setVisibility(View.VISIBLE);
            } else {
                mButton.setVisibility(View.GONE);
            }
        }

        @Override
        public void onPageScrollStateChanged(int state) {

        }
    }

  public class GuidePagerAdapter extends PagerAdapter {
        private List<View> viewList;

        public GuidePagerAdapter(List<View> viewList) {
            this.viewList = viewList;
        }
        /**
         * 返回页面的个数
         *
         * @return
         */
        @Override
        public int getCount() {
            if (viewList != null) {
                return viewList.size();
            }
            return 0;
        }

        /**
         * 判断是否由对象生成界面
         *
         * @param view
         * @param object
         * @return
         */
        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == object;
        }

        /**
         * 初始化position位置的界面
         *
         * @param container
         * @param position
         * @return
         */
        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            ((ViewPager) container).addView(viewList.get(position), 0);
            return viewList.get(position);
        }

        /**
         * 移除页面
         *
         * @param container
         * @param position
         * @param object
         */
        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            ((ViewPager) container).removeView(viewList.get(position));
        }
    }

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval" >

    <corners android:radius="5dp" />
    <solid android:color="@android:color/white" />

</shape>

<shape xmlns:android="http://schemas.android.com/apk/res/android"  android:shape="oval" >

    <corners android:radius="5dp" />
    <solid android:color="@android:color/darker_gray" />

</shape>

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
    <corners android:radius="10dp" />
    <solid android:color="@android:color/holo_blue_bright" />

</shape>