First of all, add the following dependencies to build.gradle in app, banner is the frame of carousel chart, glide is the frame of picture loading.

implementation 'com.youth.banner:banner:1.4.9'
implementation 'com.github.bumptech.glide:glide:4.7.1'
annotationProcessor 'com.github.bumptech.glide:compiler:4.7.1'

//The following dependency okhttp and okhttputil are used for network requests
implementation 'com.squareup.okhttp3:okhttp:4.3.0'
implementation 'com.squareup.okio:okio:2.4.3'
implementation 'com.zhy:okhttputils:2.6.2'

Then write the layout that needs to use the rotation chart. Please modify it according to your own project requirements. A simple example is as follows:

<com.youth.banner.Banner
android:id="@+id/banner"
android:layout_width="match_parent"
android:layout_height="180dp"
/>

Due to the different scale requirements of different project rotation chart, it is recommended not to write in the layout file. In my example later, I will use code to dynamically change the aspect ratio of banner control.

After that, I will deal with the business logic flow of the carousel chart: ① when opening the APP, I will get the carousel chart data json obtained by the last request server from SharedPreferences and load it. If SharedPreferences has no data, I will manually write the default data. ② Request the server to obtain the latest data of the carousel chart, and save the obtained json to SharedPreferences after successful request. ③ Analyze the new data requested and update the carousel chart

Next, I will post all the codes related to banner directly, and the important parts will be explained in the notes:

First add the following required global variables:

private Banner banner;
private ArrayList<String> list_path;
private ArrayList<String> list_title;
private ArrayList<String> list_href;

And the class needs to inherit OnBannerListener to set the click event:

public class BannerDemo extends AppCompatActivity implements OnBannerListener

Then set the width height ratio of banner control and call the initialization and update methods in oncreate method:

banner = (Banner)findViewById(R.id.banner);
WindowManager wm1 = getActivity().getWindowManager();
int width = wm1.getDefaultDisplay().getWidth();
LinearLayout.LayoutParams linearParams =(LinearLayout.LayoutParams) banner.getLayoutParams();
linearParams.width = width;
linearParams.height = width*9/16;
banner.setLayoutParams(linearParams);	//Set the carousel control to a 16 / 9 scale
initView();
updateBanner();

Finally, complete the initialization and update methods and set the click event:

 private void updateBanner(){
    String host = new Defines().SERVER_HOST+"getBanner";
    OkHttpUtils
            .post()
            .url(host)
            .build()
            .execute(new StringCallback() {

                @Override
                public void onError(Call call, Exception e, int id) {
                    Toasty.error(getActivity(), "Server request failed", Toast.LENGTH_SHORT, true).show();
                }

                @Override
                public void onResponse(String response, int id) {
                    try {
                        JSONObject jsonObject = new JSONObject(response);
                        int code = jsonObject.getInt("code");
                        if (code==200) {
                        	//If the request is successful, clear the current data, write it back and save it to SharedPreferences 
                            list_path.clear();
                            list_href.clear();
                            list_title.clear();
                            JSONArray dataArray = jsonObject.getJSONArray("data");
                            final SharedPreferences sp = getActivity().getSharedPreferences("banner", Context.MODE_PRIVATE);
                            sp.edit().putString("jsonList",dataArray.toString()).commit();
                            ArrayList<String> update_list_path = new ArrayList<>();
                            ArrayList<String> update_list_title = new ArrayList<>();
                            ArrayList<String> update_list_href = new ArrayList<>();
                            if(dataArray.length()!=0){
                                for(int i=0;i<dataArray.length();i++){
                                    JSONObject thisBanner = dataArray.getJSONObject(i);
                                    update_list_title.add(thisBanner.getString("title"));
                                    update_list_path.add(thisBanner.getString("img_url"));
                                    update_list_href.add(thisBanner.getString("href"));
                                }
                            }else{
                                update_list_title.add("No_Banner_Title");
                                update_list_path.add("No_Banner_Url");
                                update_list_href.add("No_Banner_Href");
                            }
                            list_path = update_list_path;
                            list_title = update_list_title;
                            list_href = update_list_href;
                            //Note that the global variable parameter cannot be used in the update method of banner. Update list path and update list title are all redefined variables
                            banner.update(update_list_path,update_list_title);
                        } else {
                            Toasty.error(getActivity(),jsonObject.getString("msg"), Toast.LENGTH_SHORT, true).show();
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                        Toasty.error(getActivity(),"Failed to get the rotation chart",Toast.LENGTH_LONG).show();
                    }
                }
            });
}

private void initView(){
    //Set of place picture addresses
    list_path = new ArrayList<>();
    //Set of titles
    list_title = new ArrayList<>();
    //Put linked collection
    list_href = new ArrayList<>();
    final SharedPreferences sp = getActivity().getSharedPreferences("banner", Context.MODE_PRIVATE);
    try {
        String bannerArrayJson = sp.getString("jsonList",null);
        if(bannerArrayJson!=null){
            JSONArray dataArray = new JSONArray(bannerArrayJson);
            if(dataArray.length()!=0){
                for(int i=0;i<dataArray.length();i++){
                    JSONObject thisBanner = dataArray.getJSONObject(i);
                    list_title.add(thisBanner.getString("title"));
                    list_path.add(thisBanner.getString("img_url"));
                    list_href.add(thisBanner.getString("href"));
                }
            }else{
                list_path.add("No_Banner_Url");
                list_title.add("No_Banner_Title");
                list_href.add("No_Banner_Href");
            }
        }else{
            list_path.add("No_Banner_Url");
            list_title.add("No_Banner_Title");
            list_href.add("No_Banner_Href");
        }
    } catch (JSONException e) {

    }
    //Set the built-in style. There are six ways to click in one by one.
    banner.setBannerStyle(2);
    //Set picture loader, picture loader is below
    banner.setImageLoader(new MyLoader());
    //Set picture web address or collection of addresses
    banner.setImages(list_path);
    //Set the animation effect of the carousel, including a variety of special effects, which can be found in the method and experienced one by one
    banner.setBannerAnimation(Transformer.DepthPage);
    //Set the title set of the carousel
    banner.setBannerTitles(list_title);
    //Set rotation interval
    banner.setDelayTime(3000);
    //Set whether it is auto rotation. The default is yes.
    banner.isAutoPlay(true);
    //Set the position of the indicator, small dot, left middle right.
    banner.setIndicatorGravity(BannerConfig.CENTER)
            //The above content can be written as a chain layout, which is the monitoring of the carousel chart. More important. The method is below.
            .setOnBannerListener(this)
            //The last call method must be invoked to start the chart.
            .start();
}
//Set click event
@Override
public void OnBannerClick(int position) {
    if(!list_href.get(position).equals("No_Banner_Href")){
        Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setData(Uri.parse(list_href.get(position)));
        startActivity(intent);
    }else{
        Toasty.info(getActivity(),"Failed to load the carousel chart",Toast.LENGTH_SHORT).show();
    }
}
//The user-defined image loader uses glide to load images. The placeholder and error are the bitmap of loading and loading failure respectively
private class MyLoader extends ImageLoader {
    @Override
    public void displayImage(Context context, Object path, ImageView imageView) {
        RequestOptions options = RequestOptions.centerInsideTransform().placeholder(R.drawable.loadingbanner).error(R.drawable.loadingbanner);
        Glide.with(context).load((String) path).apply(options).into(imageView);
    }
}