異常IllegalStateException終於解決了

還是由於一個類中使用xutils進行聯網請求，開啟了兩個線程，導致在得到請求數據之前viewPagerAdapter就已經setAdapter了，setAdapter時getCount是0，但是數據加載完成后，adapter並沒有notify，導致異常。確實是由於數據改變了卻沒有更新adapter。

在構造器中，request（）聯網請求數據開啟了分線程，setAdapter在主線程中直接執行。在viewsDetail加載完成后adapter.notify重寫加載就可以了

 private final PagerAdapter adapter = new PagerAdapter() {
        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            View view = viewsDetail.get(position);
            container.addView(view);
            return view;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            vp_news_pager.removeView((View) object);
        }

        @Override
        public int getCount() {
            LogUtils.e("TAG" + viewsDetail.size());
            return viewsDetail.size();
        }

        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == object;
        }
    };
    private ArrayList<String> newsDetailTitles;
    private List<NewsBean.DataEntity.ChildrenEntity> children;


    public NewsPager(Context context) {
        activity = (Activity) context;

        view = View.inflate(activity, R.layout.news_pager, null);
        x.view().inject(this, view);
        title_pager = (TextView) view.findViewById(R.id.title_pager);

        ib_base_pager = (ImageButton) view.findViewById(R.id.ib_base_pager);
        ib_base_pager.setVisibility(View.VISIBLE);
        ib_base_pager.setOnClickListener(onClickListener);
        title_pager.setText("新聞");


        request();


        vp_news_pager.setAdapter(adapter);

    }

    private void initViewsDetail() {
        LogUtils.e("傳輸");

        NewsDetailPager newsDetailPager = new NewsDetailPager(activity, children);
        View view = newsDetailPager.initView();
        viewsDetail.add(view);

        TopicDetailPager topicDetailPager = new TopicDetailPager(activity);
        viewsDetail.add(topicDetailPager.initView());
        PhotosDetailPager photosDetailPager = new PhotosDetailPager(activity);
        viewsDetail.add(photosDetailPager.initView());
        InteractDetailPager interactDetailPager = new InteractDetailPager(activity);
        viewsDetail.add(interactDetailPager.initView());
        LogUtils.e("傳輸完成");
    }

    private NewsBean newsBean;

    private void request() {
        RequestParams entity = new RequestParams(ContentUtils.REQUEST);
        Callback.CommonCallback<? extends Object> callback = new Callback.CommonCallback<String>() {
            @Override
            public void onSuccess(String result) {
                LogUtils.e("request" + result);

                Gson gson = new Gson();
                newsBean = gson.fromJson(result, NewsBean.class);
                String title = newsBean.getData().get(0).getChildren().get(0).getTitle();
                LogUtils.e("title=========" + title);

                setLeftData(newsBean);
                getNewsDetailData(newsBean);

            }

            @Override
            public void onError(Throwable ex, boolean isOnCallback) {
                LogUtils.e("request" + ex);
            }

            @Override
            public void onCancelled(CancelledException cex) {

            }

            @Override
            public void onFinished() {
                LogUtils.e("request");
            }
        };
        x.http().get(entity, callback);
    }

    private void getNewsDetailData(NewsBean newsBean) {
        children = newsBean.getData().get(0).getChildren();
        int size = children.size();
        newsDetailTitles = new ArrayList<>();
        for (int i = 0; i < size; i++) {
            newsDetailTitles.add(children.get(i).getTitle());
            LogUtils.e("title===" + children.get(i).getTitle() + size);
        }
        initViewsDetail();
        adapter.notifyDataSetChanged();
    }