引导页

1.布局

<?xml version="1.0" encoding="utf-8"?>

<android.support.v4.view.ViewPager
    android:id="@+id/vp"
    android:layout_width="match_parent"
    android:layout_height="match_parent"></android.support.v4.view.ViewPager>

<RadioGroup
    android:id="@+id/radio_view"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:orientation="horizontal">

    <RadioButton
        android:id="@+id/btn1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <RadioButton
        android:id="@+id/btn2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <RadioButton
        android:id="@+id/btn3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <RadioButton
        android:id="@+id/btn4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</RadioGroup>

<Button
    android:id="@+id/tiyan"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@id/radio"
    android:layout_centerHorizontal="true"
    android:text="立即体验"
    android:visibility="gone" />

2.MainActivity

public class MainActivity extends AppCompatActivity {

private ViewPager vp;
private RadioGroup radio;
private Button tiyan;
ArrayList<Integer> alist = new ArrayList<>();
private MyAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    vp = findViewById(R.id.vp);
    radio = findViewById(R.id.radio_view);
    tiyan = findViewById(R.id.tiyan);
    //添加图片
    alist.add(R.drawable.p1);
    alist.add(R.drawable.p2);
    alist.add(R.drawable.p3);
    alist.add(R.drawable.p4);
    //适配器
    adapter = new MyAdapter();
    vp.setAdapter(adapter);
    radio.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            switch (checkedId){
                case R.id.btn1:
                    vp.setCurrentItem(0,false);
                    break;
                case R.id.btn2:
                    vp.setCurrentItem(1,false);
                    break;
                case R.id.btn3:
                    vp.setCurrentItem(2,false);
                    break;
                case R.id.btn4:
                    vp.setCurrentItem(3,false);
                    break;
            }
        }
    });

    //新的滑动监听
    vp.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int i, float v, int i1) {

        }

        @Override
        public void onPageSelected(int i) {
        //radio.getChildAt(i).getId()里写i 不写alist.get(i)
            radio.check(radio.getChildAt(i).getId());
            //当滑动到最后一页 显示立即体验按钮
            if (i == alist.size() - 1) {
                //显示
                tiyan.setVisibility(View.VISIBLE);
            } else {
                //隐藏
                tiyan.setVisibility(View.GONE);
            }
        }

        @Override
        public void onPageScrollStateChanged(int i) {

        }
    });

}

private class MyAdapter extends PagerAdapter {
    @Override
    public int getCount() {
        return alist.size();
    }

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

    /*
    优化图片
     */
    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        ImageView imageView = new ImageView(MainActivity.this);
        imageView.setImageResource(alist.get(position));
        imageView.setScaleType(ImageView.ScaleType.FIT_XY);
        //将图片添加到容器中
        container.addView(imageView);
        //返回图片
        return imageView;
    }

    /*
    消灭条目
     */
    @Override
    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
        container.removeView((View) object);
    }
}

}