自动轮播activity

//首先handle

Handler handler=new Handler(){    @Override    public void handleMessage(Message msg) {        if (msg.what==0){            vp.setCurrentItem(vp.getCurrentItem()+1);            handler.sendEmptyMessageDelayed(0,2000);        }    }};

//-------------------------获取数据

  private void getDataFromNet() {        AsyncTask<Void, Void, String> asyncTask = new AsyncTask<Void, Void, String>() {            @Override            protected String doInBackground(Void... voids) {
                String path = "http://www.yulin520.com/a2a/impressApi/news/mergeList?pageSize=5&page=1";
                try {                    URL url = new URL(path);
                    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 = streamToString(inputStream,"utf-8");
                        return json;
                    }
                } catch (Exception e) {                    e.printStackTrace();                }
                return null;            }
            @Override            protected void onPostExecute(String s) {                //打印以下数据看看是否获取到                Log.i("----",s);
                if (s != null){                    Gson gson = new Gson();
                    DataDataBean dataDataBean = gson.fromJson(s, DataDataBean.class);
                    List<DataDataBean.DataBean> list = dataDataBean.getData();
                    //给viewPager设置适配器                    MyAdapter myAdapter = new MyAdapter(MainActivity.this, list,handler);
                    //设置适配器                    viewPager.setAdapter(myAdapter);
                    //3.根据集合的长度动态添加小圆点...linearLayout                    initDoc(list);
                    //2.手动的可以无限滑动                    viewPager.setCurrentItem(list.size()*100000);//设置当前展示中间某个足够大的位置
                    handler.sendEmptyMessageDelayed(0,2000);//发送一个延时的空消息
                    //viewPage设置监听事件                    viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {                        @Override                        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
                        }
                        /**                         * 当选中某个页面的时候,把当前的小圆点背景变成绿色                         * @param position                         */                        @Override                        public void onPageSelected(int position) {
                            for (int i=0;i<images.size();i++){                                if (i == position%images.size()){
                                    images.get(i).setImageResource(R.drawable.shape_01);                                }else {                                    images.get(i).setImageResource(R.drawable.shape_02);                                }
                            }
                        }
                        @Override                        public void onPageScrollStateChanged(int state) {
                        }                    });                }
            }        };
        asyncTask.execute();
    }
//-************************************************************动态添加小点
  * 动态添加小圆点     * @param list     */    private void initDoc(List<DataDataBean.DataBean> list) {        //1.需要一个集合记录一下小圆点的imageView控件        images = new ArrayList<ImageView>();        //2...linearLayout上面的视图清空一下再去添加        linearLayout.removeAllViews();
        for (int i=0;i<list.size();i++){            ImageView imageView = new ImageView(MainActivity.this);
            if (i==0){                imageView.setImageResource(R.drawable.shape_01);            }else {                imageView.setImageResource(R.drawable.shape_02);            }
            //添加到集合去            images.add(imageView);            //添加到线性布局上
            //这是布局参数,,刚开始小圆点之间没有距离,所以使用java代码指定宽度高度,并且指定小圆点之间的距离            LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT);
            params.setMargins(5,0,5,0);
            linearLayout.addView(imageView,params);        }
    }
//字符串转化
 private String streamToString(InputStream inputStream,String charset) {        try {            InputStreamReader inputStreamReader = new InputStreamReader(inputStream,charset);
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);            String s = null;            StringBuilder builder = new StringBuilder();            while ((s = bufferedReader.readLine()) != null){                builder.append(s);            }
            bufferedReader.close();            return builder.toString();
        } catch (Exception e) {            e.printStackTrace();        }
        return  null;    }