android 引导页滑动

public class GuideActivity extends BaseActivity implements ViewPager.OnPageChangeListener{
        private ViewPager vpSlide;//滑动界面
        private int [] imageArray;//图片数组
        private List<View> viewList;//图片集合
        private Button btnInto;//进入按钮

        @Override
        protected int getView() {
            return R.layout.activity_guide;
        }

        @Override
        protected void initView() {
            //隐藏状态栏和导航栏
            Common.hideBar(this);
            btnInto = findViewById(R.id.btn_into);
            vpSlide = findViewById(R.id.vp_slide);
            //实例化图片资源
            imageArray = new int[]{R.drawable.icon_1,R.drawable.icon_2,R.drawable.icon_3};
            viewList= new ArrayList<View>();
        }

        @Override
        protected void method() {
            initViewPager();
            setClick();
        }

        /**
         * 加载图片ViewPager
         */
        private void initViewPager() {
            //循环创建View并加入到集合中
            int len = imageArray.length;
            for (int i = 0;i<len;i++){
                //将ImageView加入到集合中
                ImageView imageView = new ImageView(this);
                imageView.setBackgroundResource(imageArray[i]);
                viewList.add(imageView);
            }
            //View集合初始化好后，设置Adapter
            vpSlide.setAdapter(new GuideAdapter(viewList));
            //设置滑动监听
            vpSlide.setOnPageChangeListener(this);
        }


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

        }

        /**
         * 滑动后的监听
         * 判断是否是最后一页，若是则显示按钮
         */
        @Override
        public void onPageSelected(int position) {
            if (position == imageArray.length - 1){
                btnInto.setVisibility(View.VISIBLE);
            }else {
                btnInto.setVisibility(View.GONE);
            }
        }

        @Override
        public void onPageScrollStateChanged(int state) {

        }

        private void setClick() {
            btnInto.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    startActivity(new Intent(GuideActivity.this,MainActivity.class));
                    GuideActivity.this.finish();
                }
            });
        }

}

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

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

    <Button
        android:id="@+id/btn_into"
        android:layout_width="80dp"
        android:layout_height="45dp"
        android:text="进入"
        android:visibility="gone"
        android:textColor="#FFF"
        android:textSize="18sp"
        android:background="@drawable/splash_btn_shape"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"/>
</RelativeLayout>