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我在我的應用程序中有一個View Pager。 View分頁器從ImageView中顯示JSON &中的Imagepath。 View尋呼機第一次工作。但是當這些值改變時，它會返回一個錯誤。在視圖尋呼機中無法解決notifyDataSetChanged錯誤？
但我已通知PagerAdapter關於notifyDataSetChanged。
java.lang.IllegalStateException: The application's PagerAdapter changed the adapter's contents without calling PagerAdapter#notifyDataSetChanged! Expected adapter item count: 1, found: 0 Pager id: com.hello.hello:id/pager Pager class: class com.hello.hello.utils.ImageViewTouchViewPager Problematic adapter: class com.hello.hello.utils.ZoomAdapter
的AsyncTask 1
public class FetchPromo extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
promoList = new ArrayList<String>();
progress = new ProgressDialog(getActivity());
progress.setMessage("Fetching Promotions from your Neighbouring store");
progress.show();
progress.setCanceledOnTouchOutside(false);
}
@Override
protected Void doInBackground(Void... params) {
String url = "http://46.101.126.31/mobileapp/gps/api.php?rquest=get_promotions&latitude=" + userLocation.getLatitude() + "&longitude=" + userLocation.getLongitude();
Log.d("Path", url);
try {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder().url(url).build();
Response response = client.newCall(request).execute();
String jsonData = response.body().string();
try {
JSONObject jsonObject = new JSONObject(jsonData);
store_name = jsonObject.getString("store_name");
JSONArray promo_path = jsonObject.getJSONArray("image_path");
Log.d("Path", store_name);
for (int i = 0; i < promo_path.length(); i++) {
String path = promo_path.getString(i);
promoList.add(path);
}
} catch (JSONException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
store.setText(store_name);
if (promoList.isEmpty()) {
promoList.add(placeholder);
}
mZoomAdapter = new ZoomAdapter(getActivity(), promoList);
mViewPager.setAdapter(mZoomAdapter);
mZoomAdapter.notifyDataSetChanged();
new FetchStore().execute();
progress.dismiss();
}
}
AYNCTASK 2（其中，數據必須被重新加載）
public class FetchPromoByID extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
promoList.clear();
progress = new ProgressDialog(getActivity());
progress.setMessage("Fetching Promotions from your Choosen store");
progress.show();
progress.setCanceledOnTouchOutside(false);
}
@Override
protected Void doInBackground(Void... params) {
String url = "http://46.121.116.31/mobileapp/gps/api.php?rquest=get_promotions_by_store_id&store_id=" + Choosen_id;
Log.d("FetchPromoByID", url);
try {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder().url(url).build();
Response response = client.newCall(request).execute();
String jsonData = response.body().string();
try {
JSONObject jsonObject = new JSONObject(jsonData);
JSONArray promo_path = jsonObject.getJSONArray("image_path");
store_name = jsonObject.getString("store_name");
Log.d("Path", store_name);
for (int i = 0; i < promo_path.length(); i++) {
String path = promo_path.getString(i);
promoList.add(path);
}
} catch (JSONException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
mZoomAdapter = new ZoomAdapter(getActivity(), promoList);
mViewPager.setAdapter(mZoomAdapter);
mZoomAdapter.notifyDataSetChanged();
new FetchStore().execute();
progress.dismiss();
}
}
ADAPTER
public class ZoomAdapter extends PagerAdapter {
private Context context;
private ArrayList<String> IMAGES = new ArrayList<>();
public ZoomAdapter(Context context, ArrayList<String> IMAGES) {
this.IMAGES = IMAGES;
this.context = context;
}
@Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
@Override
public int getCount() {
return IMAGES.size();
}
@Override
public View instantiateItem(ViewGroup container, int position) {
String url = IMAGES.get(position);
PhotoView photoView = new PhotoView(container.getContext());
// Now just add PhotoView to ViewPager and return it
container.addView(photoView, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
Picasso.with(context)
.load(url)
.fit()
.into(photoView);
return photoView;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View) object);
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
}
FetchStore
public class FetchStore extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
storeList = new ArrayList<String>();
storeID = new ArrayList<String>();
}
@Override
protected Void doInBackground(Void... params) {
String url = "http://46.101.116.31/mobileapp/gps/api.php?rquest=get_store";
try {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder().url(url).build();
Response response = client.newCall(request).execute();
String jsonData = response.body().string();
try {
JSONObject jsonObject = new JSONObject(jsonData);
JSONArray storearray = jsonObject.getJSONArray("stores");
for (int i = 0; i < storearray.length(); i++) {
JSONObject storeobj = storearray.getJSONObject(i);
String store = storeobj.getString("name");
String ID = storeobj.getString("id");
storeList.add(store);
storeID.add(ID);
}
} catch (JSONException e) {
e.printStackTrace();
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
choose.setVisibility(View.VISIBLE);
}
}
我發現很多這樣類似的問題。但沒有任何解決方案爲我工作。請指導我。
由於提前
郵編（）。 –
@JagjitSingh張貼。 – user3467240
嘗試通過設置setOffscreenPageLimit mViewPager.setOffscreenPageLimit（promoList.size（））; –