Banner介绍

添加依赖

implementation 'com.youth.banner:banner:1.4.10'

MainActivity主界面

public class MainActivity extends AppCompatActivity {

    private Banner banner;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        banner = findViewById(R.id.banner);
        //设置banner样式
        banner.setBannerStyle(BannerConfig.NUM_INDICATOR);
        //BannerConfig.CIRCLE_INDICATOR 小圆点 但是没有标题
        //BannerConfig.CIRCLE_INDICATOR_TITLE  显示圆形指示器和标题
        //BannerConfig.NUM_INDICATOR   显示数字指示器
        // BannerConfig.NUM_INDICATOR_TITLE 显示数字指示器和标题
        //banner.setIndicatorGravity(BannerConfig.LEFT);//指示器中间位置
        //BannerConfig.CENTER
        //BannerConfig.RIGHT
        //BannerConfig.LEFT
        //图片加载器
        banner.setImageLoader(new ImageLoaderInterface<ImageView>() {

            @Override
            public void displayImage(Context context, Object path, ImageView imageView) {
                BannerResponse.Banner banner= (BannerResponse.Banner) path;
                ImageLoader.getInstance().displayImage(banner.getPicUrl(),imageView);
            }

            @Override
            public ImageView createImageView(Context context) {
                ImageView imageView=new ImageView(context);
                imageView.setScaleType(ImageView.ScaleType.FIT_XY);
                return imageView;
            }
        });
        initData();
    }

    private void initData() {
        NetUtil.requestData("https://api.tianapi.com/wxnew/?key=c4aa776e0a51d57d6750511e2baa46b6&num=6&page=1", BannerResponse.class, new NetUtil.CallBack<BannerResponse>() {
            @Override
            public void getdata(BannerResponse o) {
                //设置图片集合
                banner.setImages(o.getNewslist());
                //设置标题源
                banner.setBannerTitles(getTitles(o));
                //banner设置方法全部调用完毕时最后调用
                banner.start();
            }
        });
    }
    private List<String> getTitles(BannerResponse bannerResponse) {
        List<String> result = new ArrayList<>();
        for (BannerResponse.Banner banner: bannerResponse.getNewslist()) {
            result.add(banner.getTitle());
        }
        return result;
    }
}

工具类NetUtil

public class NetUtil {

    //接口
    public interface CallBack<T>{
        void getdata(T t);
    }
    //异步任务
    public static void requestData(String strUrl, final Class clazz, final CallBack callBack){
        new AsyncTask<String, Void, Object>() {
            @Override
            protected Object doInBackground(String... strings) {
                return NetUtil.requestData(strings[0],clazz);
            }

            @Override
            protected void onPostExecute(Object o) {
                callBack.getdata(o);
            }
        }.execute(strUrl);
    }
    //网络解析
    public static <T> T requestData(String url,Class clazz){
        T t= (T) new Gson().fromJson(NetUtil.requestData(url),clazz);
        return t;
    }
    //网络请求
    public static String requestData(String str){
        String result="";
        try {
            //定义地址
            URL url=new URL(str);
            //打开连接
            HttpURLConnection urlConnection= (HttpURLConnection) url.openConnection();
            //请求方法
            urlConnection.setRequestMethod("GET");
            //读取超时
            urlConnection.setReadTimeout(5000);
            //连接超时
            urlConnection.setConnectTimeout(5000);
            if (urlConnection.getResponseCode()==200){
                result = NetUtil.StreamToString(urlConnection.getInputStream());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
    //字节流转换为字符流
    private static String StreamToString(InputStream inputStream) throws IOException {
        InputStreamReader inputStreamReader=new InputStreamReader(inputStream);
        BufferedReader buff=new BufferedReader(inputStreamReader);
        StringBuilder builder=new StringBuilder();
        for (String imp=buff.readLine();imp!=null;imp=buff.readLine()){
            builder.append(imp);
        }
        return builder.toString();
    }
}

RannerResponse

public class BannerResponse {
    private int code;
    private String msg;
    private List<Banner> newslist;
    private final int SUCCESS_CODE = 200;

    public boolean isSuccess() {
        return code == SUCCESS_CODE;
    }

    public int getCode() {
        return code;
    }

    public String getMsg() {
        return msg;
    }

    public List<Banner> getNewslist() {
        return newslist;
    }

    public class Banner {
        private String title;
        private String picUrl;

        public String getTitle() {
            return title;
        }

        public String getPicUrl() {
            return picUrl;
        }
    }
}

App图片处理

public class App extends Application {

    @Override
    public void onCreate() {
        super.onCreate();

        ImageLoader.getInstance().init(
                new ImageLoaderConfiguration.Builder(this)
                        .memoryCacheSizePercentage(10)
                        .discCacheSize(50 * 1024 * 1024)
                        .defaultDisplayImageOptions(
                                new DisplayImageOptions.Builder()
                                        .showImageOnFail(R.mipmap.ic_launcher)
                                        .showImageOnLoading(R.mipmap.ic_launcher)
                                        .cacheInMemory(true)
                                        .cacheOnDisk(true)
                                        .build()
                        )
                        .build()
        );
    }
}