ImageView控件图片轮播

Activity中，获取数据

public class MainActivity extends AppCompatActivity {

    private ImageView imageView;
    private List list = new ArrayList<>();

    private int index = 0;
    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            if (msg.what == 0){
                //接到消息之后,,,切换图片显示
                index ++;
                ImageLoader.getInstance().displayImage(list.get(index %list.size()),imageView,ImageLoaderUtil.getDefaultOption());

                //再次发送
                handler.sendEmptyMessageDelayed(0,3000);

            }
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        imageView = (ImageView) findViewById(R.id.image_view);

        getDataFromNet();
    }

    private void getDataFromNet() {

        AsyncTask asyncTask = new AsyncTask() {
            @Override
            protected String doInBackground(Void... voids) {
                try {
                    URL url = new URL("http://apis.juhe.cn/cook/query?key=65481ae0fb17703c15a794aebaec93c5&menu=%E8%A5%BF%E7%BA%A2%E6%9F%BF&rn=10&pn=3");

                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();

                    connection.setRequestMethod("GET");
                    connection.setReadTimeout(5000);
                    connection.setConnectTimeout(5000);

                    int responseCode = connection.getResponseCode();
                    if (responseCode == 200){
                        InputStream inputStream = connection.getInputStream();

                        String json = StringUtil.streamToString(inputStream,"utf-8");

                        return json;

                    }
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }


                return null;
            }

            @Override
            protected void onPostExecute(String s) {
                //解析
                Gson gson = new Gson();
                DataDataBean dataDataBean = gson.fromJson(s, DataDataBean.class);

                List steps = dataDataBean.getResult().getData().get(0).getSteps();

                for (DataDataBean.ResultBean.DataBean.StepsBean st: steps) {
                    list.add(st.getImg());
                }

                //现在图片集合有数据,,,,展示图片,,,展示第一张图片
                ImageLoader.getInstance().displayImage(list.get(0),imageView,ImageLoaderUtil.getDefaultOption());

                //发送延时消息
                handler.sendEmptyMessageDelayed(0,3000);
            }
        };

        asyncTask.execute();

    }
}

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