Realization of Automatic Cyclic Carousel Map by viewpager

In this paper, we share the specific code of viewpager automatic cyclic carousel diagram for your reference. The specific contents are as follows

Layout file

android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<RelativeLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content">
 <androidx.viewpager.widget.ViewPager
  android:id="@+id/vp_adv"
  android:layout_width="match_parent"
  android:layout_height="160dp"/>
<LinearLayout
  android:id="@+id/View_indicator"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_below="@id/vp_adv"
  android:layout_marginTop="-25dp"
  android:orientation="horizontal"
  android:gravity="right">
 </LinearLayout>
 </RelativeLayout>
</LinearLayout>

Core code

public class MainActivity extends AppCompatActivity {
 private ImageView indicator;// Represents a dot indicator 
 private ImageView [] indicators;// Array for holding dot indicators 
 private boolean iscontinue = true;
 private ViewPager viewPager;
 private ViewGroup viewGroup;
 private ArrayList<Fragment> fragments;
 List<Integer> imgs = null;
 private AtomicInteger index = new AtomicInteger();
 private Handler viewHandler= new Handler(){
 @Override
 public void handleMessage(@NonNull Message msg) {
  super.handleMessage(msg);
  viewPager.setCurrentItem(msg.what);
 }
 };

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 initView();
 }
 public void initView(){
 viewPager=findViewById(R.id.vp_adv);
 viewGroup=findViewById(R.id.View_indicator);
 //4 Ad pictures are loaded into the collection and saved 
 List<View> listPics = new ArrayList<>();
 ImageView img1 = new ImageView(this);
 img1.setBackgroundResource(R.mipmap.food1);
 listPics.add(img1);
 ImageView img2 = new ImageView(this);
 img1.setBackgroundResource(R.mipmap.shop2);
 listPics.add(img2);
 ImageView img3 = new ImageView(this);
 img1.setBackgroundResource(R.mipmap.shop3);
 listPics.add(img3);
 ImageView img4 = new ImageView(this);
 img1.setBackgroundResource(R.mipmap.shop4);
 listPics.add(img4);
 initFragments();
 // Dynamic setting 4 Dot attribute 
 indicators = new ImageView[listPics.size()];
 for(int i=0;i<indicators.length;i++){
  indicator = new ImageView(this);
  indicator.setLayoutParams(new LinearLayout.LayoutParams(40,40));
  indicator.setPadding(5,5,5,5);
  indicators[i] = indicator;
  if(i == 0){
  indicators[i].setBackgroundResource(R.drawable.ic_launcher_background);
  }else{
  indicators[i].setBackgroundResource(R.drawable.ic_launcher_foreground);
  }
  viewGroup.addView(indicators[i]);
 }
 // Settings ViewPager Adapter 
 viewPager.setAdapter(new pagerAdapter(getSupportFragmentManager()));

 // Settings viewPager Listener 
 viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
  @Override
  public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

  }

  @Override
  public void onPageSelected(int position) {
  index.getAndSet(position);
  for(int i = 0;i <indicators.length; i ++){
   if(i ==position){
   indicators[i].setBackgroundResource(R.drawable.a1);
   }else{
   indicators[i].setBackgroundResource(R.drawable.a2);
   }
  }

  }

  @Override
  public void onPageScrollStateChanged(int state) {

  }
 });
 viewPager.setOnTouchListener(new View.OnTouchListener() {
  @Override
  public boolean onTouch(View view, MotionEvent motionEvent) {
  switch (motionEvent.getAction()){
   case MotionEvent.ACTION_DOWN:
   iscontinue = false;
   break;
   case MotionEvent.ACTION_UP:
   iscontinue = true;
   break;
  }
  return false;
  }
 });
 // Use multithreaded switching UI
 new Thread(new Runnable() {
  @Override
  public void run() {
  while (true){
   if(iscontinue){
   viewHandler.sendEmptyMessage(index.get());
   whatOption();
   }
  }

  }
 }).start();
 }
 private void whatOption(){
 index.incrementAndGet();// Will the current position +1 ; 
 if(index.get()>indicators.length-1){
  index.getAndAdd(-4);
 }
 try {
  Thread.sleep(2000);
 } catch (InterruptedException e) {
  e.printStackTrace();
 }
 }
 private void initFragments() {
 imgs = new ArrayList<Integer>();
 imgs.add(R.mipmap.timg1);
 imgs.add(R.mipmap.timg2);
 imgs.add(R.mipmap.timg3);
 imgs.add(R.mipmap.timg4);

 }
 class pagerAdapter extends FragmentPagerAdapter{

 public pagerAdapter(FragmentManager fm) {
  super(fm);
 }

 @Override
 public Fragment getItem(int arg0) {
  // Get the object to display and initialize the picture 
  MyFragment fm = new MyFragment();
  fm.setUrl(imgs.get(arg0));

  return fm;
 }

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

 }
}

class MyPagerAdapter extends PagerAdapter{
 private List<View> viewList;
 public MyPagerAdapter(List<View>viewList){
 this.viewList = viewList;
 }

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

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

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

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