Android使用ViewPager实现启动引导页效果

package cn.edu.zufe.app001;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.viewpager.widget.PagerAdapter;
import androidx.viewpager.widget.ViewPager;

import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

import java.util.ArrayList;

public class ViewPagerTwoActivity extends AppCompatActivity {

    private int[] launchImageArray = new int[]{
            R.drawable.guide_bg1,R.drawable.guide_bg2,R.drawable.guide_bg3,R.drawable.guide_bg4
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_view_pager_two);
        ViewPager vp_launch = (ViewPager)findViewById(R.id.vp_launch);
        LaunchSimpleAdapter adapter = new LaunchSimpleAdapter(this,launchImageArray);
        vp_launch.setAdapter(adapter);
        vp_launch.setCurrentItem(0);
    }

    class LaunchSimpleAdapter extends PagerAdapter{
        private Context mContext;
        private ArrayList<View> mViewList = new ArrayList<View>();
        public LaunchSimpleAdapter(final Context context, int[] imageArray){
            mContext = context;
            for(int i=0; i<imageArray.length; i++){
                View view = LayoutInflater.from(context).inflate(R.layout.item_launch,null);
                ImageView iv_launcher = (ImageView)view.findViewById(R.id.iv_launch);
                RadioGroup rg_indicate = (RadioGroup)view.findViewById(R.id.rg_indicate);
                Button btn_start = (Button)view.findViewById(R.id.btn_start);
                iv_launcher.setImageResource(imageArray[i]);
                for(int j=0; j<imageArray.length; j++){
                    RadioButton radio = new RadioButton(mContext);
                    radio.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
                    radio.setButtonDrawable(R.drawable.launch_guide);
                    radio.setPadding(10,10,10,10);
                    rg_indicate.addView(radio);
                }
                ((RadioButton)rg_indicate.getChildAt(i)).setChecked(true);
                if (i == imageArray.length-1) {
                    btn_start.setVisibility(View.VISIBLE);
                    btn_start.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            Toast.makeText(context,"欢迎您开启美好生活",Toast.LENGTH_SHORT).show();
                        }
                    });
                }
                mViewList.add(view);
            }
        }

        @Override
        public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
            container.removeView(mViewList.get(position));
        }

        @NonNull
        @Override
        public Object instantiateItem(@NonNull ViewGroup container, int position) {
            container.addView(mViewList.get(position));
            return mViewList.get(position);
        }

        @Override
        public int getCount() {
            return mViewList.size();
        }

        @Override
        public boolean isViewFromObject(@NonNull View view, @NonNull Object o) {
            return view == o;
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<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="cn.edu.zufe.app001.ViewPagerTwoActivity">

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