像这样更新两个类，可能对您有帮助！
fetchDataclass：
public class fetchData extends AsyncTask<Void,Void,Void> { String data =""; String factTitle = ""; String factDesc = ""; String factImg =""; String singleParsed =""; String DoubleParsed =""; String tripleParsed =""; Activity mContext; TextView mfactTitle,mfactDesc; ImageView mfactImg; ProgressBar mProgressbar; public fetchData(Activity context,TextView mfactTitle,TextView mfactDesc,ImageView mfactImg,ProgressBar mProgressbar){ this.context=context; this.mfactTitle=mfactTitle; this.mfactDesc=mfactDesc; this.mfactImg=mfactImg; this.mProgressbar=mProgressbar; } @Override protected Void doInBackground(Void... voids) { try { URL url = new URL("http://xxxxxx.com/api"); HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection(); InputStream inputStream = httpURLConnection.getInputStream(); BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream)); String line = ""; while(line != null){ line = bufferedReader.readLine(); data = data + line; } JSonArray JA = new JSonArray(data); for(int i =0 ;i <JA.length(); i++){ JSonObject JO = (JSONObject) JA.get(i); singleParsed = ""+JO.get("fact"); DoubleParsed = ""+JO.get("factdesc"); tripleParsed = ""+JO.get("img"); factTitle = factTitle + singleParsed; factDesc = factDesc + DoubleParsed; factImg = factImg + tripleParsed; } } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } catch (JSonException e) { e.printStackTrace(); } return null; } @Override protected void onPostExecute(Void aVoid) { super.onPostExecute(aVoid); mfactImg.setVisibility(View.VISIBLE); mfactTitle.setText(this.factTitle); mfactDesc.setText(this.factDesc); Picasso.get().load(factImg).placeholder(R.drawable.defaultthumb).into(mfactImg); mProgressBar.setVisibility(View.INVISIBLE); }}PlaceHolder片段：
public static PlaceholderFragment newInstance(int sectionNumber) { PlaceholderFragment fragment = new PlaceholderFragment(); Bundle args = new Bundle(); args.putInt(ARG_SECTION_NUMBER, sectionNumber); fragment.setArguments(args); return fragment; } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_main, container, false); factTitle = (TextView) rootView.findViewById(R.id.fact_label); factDesc = (TextView) rootView.findViewById(R.id.fact_description); factImg = (ImageView) rootView.findViewById(R.id.imageView); loader = (ProgressBar) rootView.findViewById(R.id.progressBar); fetchData process = new fetchData(getActivity(),factTitle,factDesc,factImg,loader); process.execute(); return rootView; } }
