我正在从webservice动态创建tablayout标签。 tablayout附加到viewpager。当我在viewpager中滑动页面时，应用程序崩溃并出现IllegalStateException。我搜索了这个例外，发现它可能是由于片段造成的，所以我在一些SO帖子中建议使用getChildFragmentManager。我也使用v而不是FragmentPagerAdapter，但我仍然得到相同的错误。有什么我做错了，因为我在活动中使用了相同的代码并且工作正常。
FATAL EXCEPTION: main
Process: com.nits_35.wrd, PID: 5175
java.lang.IllegalStateException: The application's PagerAdapter changed the adapter's contents without calling PagerAdapter#notifyDataSetChanged! Expected adapter item count: 4, found: 15 Pager id: com.nits_35.wrd:id/category_viewpager Pager class: class cn.trinea.android.view.autoscrollviewpager.AutoScrollViewPager Problematic adapter: class com.nits_35.wrd.views.fragments.Frag_Seller_Market$SampleFragmentPagerAdapter
at android.support.v4.view.ViewPager.populate(ViewPager.java:1167)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1116)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1642)
at android.view.View.layout(View.java:16924)
at android.view.ViewGroup.layout(ViewGroup.java:5602)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:2001)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1844)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1753)
at android.view.View.layout(View.java:16953)
at android.view.ViewGroup.layout(ViewGroup.java:5602)
at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:1193)
at android.view.View.layout(View.java:16953)
at android.view.ViewGroup.layout(ViewGroup.java:5602)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1189)
at android.view.View.layout(View.java:16953)
at android.view.ViewGroup.layout(ViewGroup.java:5602)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:396)
at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
at android.view.View.layout(View.java:16953)
at android.view.ViewGroup.layout(ViewGroup.java:5602)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1189)
at android.view.View.layout(View.java:16953)
at android.view.ViewGroup.layout(ViewGroup.java:5602)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:396)
at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
at android.view.View.layout(View.java:16953)
at android.view.ViewGroup.layout(ViewGroup.java:5602)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:2001)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1844)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1753)
at android.view.View.layout(View.java:16953)
at android.view.ViewGroup.layout(ViewGroup.java:5602)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:396)
at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
at android.view.View.layout(View.java:16953)
at android.view.ViewGroup.layout(ViewGroup.java:5602)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:2001)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1844)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1753)
at android.view.View.layout(View.java:16953)
at android.view.ViewGroup.layout(ViewGroup.java:5602)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:396)
at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
at com.android.internal.policy.PhoneWindow$DecorView.onLayout(PhoneWindow.java:2722)
at android.view.View.layout(View.java:16953)
at android.view.ViewGroup.layout(ViewGroup.java:5602)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2549)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2252)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1323)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6706)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:894)
at android.view.Choreographer.doCallbacks(Choreographer.java:696)
at android.view.Choreographer.doFrame(Choreographer.java:631)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:880)
at android.os.Handler.handleCallback(Handler.java:815)
at android.os.Handler.dispatchMessage(Handler.java:104)
at android.os.Looper.loop(Looper.java:207)
at android.app.ActivityThread.main(ActivityThread.java:5728)
at java.lang.reflect.Method.invokpublic class Frag_Seller_Market extends Fragment {
private AutoScrollViewPager category_viewpager;
private SampleFragmentPagerAdapter adapter;
public Frag_Seller_Market() {
// Required empty public constructor
}
private TabLayout seller_tabs_store;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v=inflater.inflate(R.layout.seller_fragment_market, container, false);
seller_tabs_store=(TabLayout)v.findViewById(R.id.seller_tabs_store);
category_viewpager=(AutoScrollViewPager) v.findViewById(R.id.category_viewpager);
return v;
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
if (cd.isConnectingToInternet()){
fetchCategoryList();
}else {
Toast.makeText(getActivity(),"No Internet",Toast.LENGTH_SHORT).show();
}
}
private void fetchCategoryList(){
if(arrayList!=null)arrayList.clear();
pd.setMessage("loading...");
pd.show();
StringRequest stringRequest = new StringRequest(Request.Method.GET, Utility.CATEGORYLIST,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
pd.dismiss();
System.out.println("Category_List_Response"+response);
try {
JSONObject jObj = new JSONObject(response);
if(jObj.getInt("Ack")==1){
JSONArray jsonArray = jObj.getJSONArray("CategoryList");
for(int i=0;i<jsonArray.length();i++){
JSONObject main = jsonArray.getJSONObject(i);
Model market = new Model();
market.setProduct_category_id(main.getString("id"));
market.setProduct_category_name(main.getString("name"));
arrayList.add(market);
}
if(getActivity()!=null)
category_viewpager.setAdapter(new SampleFragmentPagerAdapter(getChildFragmentManager(), getActivity(), arrayList));
seller_tabs_store.setupWithViewPager(category_viewpager);
}
} catch (JSONException e) {
// JSON error
System.out.println("jay_JSONError "+e);
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
if (error instanceof TimeoutError) {
Toast.makeText(getActivity(),getString(R.string.tooslow),Toast.LENGTH_LONG).show();
}else if (error instanceof NoConnectionError){
Toast.makeText(getActivity(),getString(R.string.nointernet),Toast.LENGTH_LONG).show();
}else if (error instanceof AuthFailureError) {
System.out.println("jay_AuthFailureError "+error);
} else if (error instanceof ServerError) {
System.out.println("sammy_ServerError "+error);
} else if (error instanceof NetworkError) {
System.out.println("sammy_NetworkError "+error);
} else if (error instanceof ParseError) {
System.out.println("sammy_ParseError "+error);
}
}
}) ;
RequestQueue requestQueue = Volley.newRequestQueue(getActivity());
requestQueue.add(stringRequest);
stringRequest.setRetryPolicy(new DefaultRetryPolicy(
10000,
DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
}
public class SampleFragmentPagerAdapter extends FragmentStatePagerAdapter {
private Context context;
private ArrayList<Model> arrayList;
public SampleFragmentPagerAdapter(FragmentManager fm, Context context, ArrayList<Model> arrayList) {
super(fm);
this.context = context;
this.arrayList=arrayList;
}
@Override
public int getCount() {
return arrayList.size();
}
@Override
public Fragment getItem(int position) {
return Frag_store_productwiselist.newInstance(arrayList.get(position).getProduct_category_id());
}
@Override
public CharSequence getPageTitle(int position) {
return arrayList.get(position).getProduct_category_name();
}
}
}
答案 0 :(得分：0)
不是每次都创建一个新的适配器，您可以根据数据是否有任何变化通知它更新视图。
所以你可以做的是：
if(sampleFragmentPagerAdapter == null){
sampleFragmentPagerAdapter = new SampleFragmentPagerAdapter(getChildFragmentManager(), getActivity(), arrayList);
}else{
sampleFragmentPagerAdapter.notifyDataSetChanged();
}
category_viewpager.setAdapter(sampleFragmentPagerAdapter);
seller_tabs_store.setupWithViewPager(category_viewpager);
制作sampleFragmentPagerAdapter，它是活动或片段中的全局对象。
答案 1 :(得分：0)
查看错误消息：
应用程序的PagerAdapter在不调用PagerAdapter＃notifyDataSetChanged的情况下更改了适配器的内容！预期的适配器项目数：4，找到：15
问题来自getCount中的PagerAdapter功能：
@Override
public int getCount() {
return arrayList.size();
}
通过此功能，每当add/remove/clear arrayList viewPagerAdapter.notifyDataSetChanged()时，您都需要致电getItemPosition。
P / s：您需要覆盖Adapter的{{1}}功能才能使其正常工作。
@Override
public int getItemPosition(Object object) {
// Causes adapter to reload all Fragments when
// notifyDataSetChanged is called
return POSITION_NONE;
}