viewPager使用时加载数据时显示IllegalStateException异常，解决不了。。。。

从newsPager中得到newsDetailTitles标题的详细内容，这是通过构造器传过来的。打印日志78行能打印，45行打印出来共size是12.但是程序出现了异常java.lang.IllegalStateException: The application‘s PagerAdapter changed the adapter‘s contents without calling PagerAdapter#notifyDataSetChanged。

从网上查询的结果是adapter中的数据改变了，却没有重新加载数据，需要在数据改变之后adapter.notifyDataSetChanged。但是找不到数据改变的地方。今天太累了，这个bug找到答案时再写。

 1 package com.atguigu.beijingnews2.pager.newsdetailpager;
 2
 3 import android.app.Activity;
 4 import android.content.Context;
 5 import android.support.v4.view.PagerAdapter;
 6 import android.support.v4.view.ViewPager;
 7 import android.view.View;
 8 import android.view.ViewGroup;
 9 import android.widget.TextView;
10
11 import com.atguigu.beijingnews2.R;
12 import com.atguigu.beijingnews2.utils.LogUtils;
13
14 import org.xutils.view.annotation.ViewInject;
15 import org.xutils.x;
16
17 import java.util.ArrayList;
18
19 /**
20  * Created by Administrator on 2016/2/18.
21  */
22 public class NewsDetailPager {
23     private Activity activity;
24     @ViewInject(R.id.vp_news_detail_paper)
25     private ViewPager vp_news_detail_paper;
26     private ArrayList<String> newsDetailTitles=new ArrayList<>() ;
27     private PagerAdapter adapter = new PagerAdapter() {
28         @Override
29         public Object instantiateItem(ViewGroup container, int position) {
30             LogUtils.e("TAG");
31 //            String title = newsDetailTitles.get(position);
32 //            textView.setText(title);
33             container.addView(views.get(position));
34             return views.get(position);
35         }
36
37         @Override
38         public void destroyItem(ViewGroup container, int position, Object object) {
39             LogUtils.e("TAG");
40             container.removeView((View) object);
41         }
42
43         @Override
44         public int getCount() {
45             LogUtils.e("TAG" + newsDetailTitles.size());
46
47             return newsDetailTitles.size();
48         }
49
50         @Override
51         public boolean isViewFromObject(View view, Object object) {
52             LogUtils.e("TAG");
53             return view == object;
54         }
55     };
56     private TextView textView;
57     ArrayList<View> views = new ArrayList<>();
58     public NewsDetailPager(Context context, ArrayList<String> newsDetailTitles ) {
59         activity = (Activity) context;
60         this.newsDetailTitles=newsDetailTitles;
61 //        initView();
62
63
64     }
65
66
67
68     public View initView() {
69         View view = View.inflate(activity, R.layout.news_detail_paper, null);
70         x.view().inject(this, view);
71         for (int i = 0; i < newsDetailTitles.size(); i++) {
72             TextView textView = new TextView(activity);
73             textView.setText(newsDetailTitles.get(i));
74             views.add(textView);
75             LogUtils.e("TAG");
76         }
77 //        textView = new TextView(activity);
78         LogUtils.e("TAG");
79         vp_news_detail_paper.setAdapter(adapter);
80         return view;
81     }
82 }

E/AndroidRuntime: FATAL EXCEPTION: main
                                                                        Process: com.atguigu.beijingnews2, PID: 1622
                                                                        java.lang.IllegalStateException: The application‘s PagerAdapter changed the adapter‘s contents without calling PagerAdapter#notifyDataSetChanged! Expected adapter item count: 0, found: 4 Pager id: com.atguigu.beijingnews2:id/vp_news_pager Pager class: class com.atguigu.beijingnews2.view.NoScrollViewPager Problematic adapter: class com.atguigu.beijingnews2.pager.NewsPager$2
                                                                            at android.support.v4.view.ViewPager.populate(ViewPager.java:999)
                                                                            at android.support.v4.view.ViewPager.populate(ViewPager.java:951)
                                                                            at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1473)
                                                                            at android.view.View.measure(View.java:16497)
                                                                            at android.widget.LinearLayout.measureVertical(LinearLayout.java:847)
                                                                            at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
                                                                            at android.view.View.measure(View.java:16497)
                                                                            at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1488)
                                                                            at android.view.View.measure(View.java:16497)
                                                                            at android.widget.LinearLayout.measureVertical(LinearLayout.java:847)
                                                                            at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
                                                                            at android.view.View.measure(View.java:16497)
                                                                            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
                                                                            at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
                                                                            at android.view.View.measure(View.java:16497)
                                                                            at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
                                                                            at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
                                                                            at android.view.View.measure(View.java:16497)