引导页

1.不用导依赖

2.写布局

<?  version=\"1.0\" encoding=\"utf-8\"?>
<RelativeLayout  ns:android=\"http://schemas.android.com/apk/res/android\"
 ns:app=\"http://schemas.android.com/apk/res-auto\"
 ns:tools=\"http://schemas.android.com/tools\"
android:layout_width=\"match_parent\"
android:layout_height=\"match_parent\"
tools:context=\".MainActivity\"
 >
<android.support.v4.view.ViewPager
    android:id=\"@+id/pag\"
    android:layout_width=\"match_parent\"
    android:layout_height=\"match_parent\"
    />
<Button
    android:id=\"@+id/button\"
    android:layout_width=\"wrap_content\"
    android:layout_height=\"wrap_content\"
    android:layout_alignParentBottom=\"true\"
    android:layout_centerHorizontal=\"true\"
    android:layout_marginBottom=\"73dp\"
    android:layout_weight=\"1\"
    android:text=\"进入\" />
<RadioGroup
    android:id=\"@+id/rg\"
    android:layout_width=\"match_parent\"
    android:layout_height=\"50dp\"
    android:orientation=\"horizontal\"
    android:layout_alignParentBottom=\"true\"
    android:gravity=\"center\"
    android:layout_alignParentLeft=\"true\"
    android:layout_weight=\"2\"/>

3.MainActivity代码

public class MainActivity extends AppCompatActivity {

private ViewPager pag;

private Button button;
private RadioGroup rg;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    pag = findViewById(R.id.pag);
    button = findViewById(R.id.button);
    //跳转
    button.set Listener(new View. Listener() {
        @Override
        public void  (View v) {
            Intent in=new Intent(MainActivity.this,Main2Activity.class);
            startActivity(in);
        }
    });
    rg = findViewById(R.id.rg);
    //数组放图片
    int arr[]={R.drawable.a1,R.drawable.a11,R.drawable.a2};
    //定义list集合  for循环
    final List<ImageView> list=new ArrayList<ImageView>();
    for (int i=0;i<arr.length;i++){
  		//定义图片
        ImageView imag=new ImageView(MainActivity.this);
        imag.setImageResource(arr[i]);
        list.add(imag);
        //写小圆点
        RadioButton rb=new RadioButton(MainActivity.this);
        rg.addView(rb);
    }
    rg.check(rg.getChildAt(0).getId());
    //适配器
    pag.setAdapter(new PagerAdapter() {
        @Override
        public int getCount() {
            return list.size();
        }

        @Override
        public boolean isViewFrom (@NonNull View view, @NonNull   o) {
            return view==o;
        }
        @NonNull
        @Override
        public   instantiateItem(@NonNull ViewGroup container, int position) {
        //设置图片
            ImageView ima=list.get(position);
            //添加图片布局
            container.addView(ima);
            return ima;
        }
        @Override
        public void destroyItem(@NonNull ViewGroup container, int position, @NonNull    ) {
        //删除布局
            container.removeView((View)  );
        }
    });

    pag.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int i, float v, int i1) {
        //判断隐藏按钮
            if (i==list.size()-1) {
                button.setVisibility(View.VISIBLE);
            }
            else {
                button.setVisibility(View.GONE);
            }
        }

        @Override
        public void onPageSelected(int i) {
        //选中页面
            rg.check(rg.getChildAt(i).getId());
        }

        @Override
        public void onPageScrollStateChanged(int i) {

        }
    });

}

}