Image Loading Library Picasso lädt kein Bild in Bildansicht

Question

Ich versuche, Android-App mit Bildergalerie erstellt mit Rasteransicht mit Bildadapter, die Daten mit Picasso-Bibliothek zu holen.aber kein Bild angezeigt wird.Es kann ein Problem des Zusammenhangs oder sein in picasso Bibliothek, aber ich bin nicht sicher, wo das Problem ist, wie ich kein error.everything funktioniert nach Logs

**package com.example.android.popmovies; 

import android.content.Context; 
import android.net.Uri; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.util.Log; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.AdapterView; 
import android.widget.BaseAdapter; 
import android.widget.GridView; 
import android.widget.ImageView; 

import com.squareup.picasso.Picasso; 

import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.InputStreamReader; 
import java.net.HttpURLConnection; 
import java.net.URL; 
import java.util.ArrayList; 

/** 
* A placeholder fragment containing a simple view. 
*/ 
public class PopMovieFragment extends Fragment { 
    ImageAdapter imageAdapter; 
    public PopMovieFragment() { 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 

     View view = inflater.inflate(R.layout.fragment_main,container,false); 

     GridView gridView = (GridView) view.findViewById(R.id.gridview); 

     imageAdapter = new ImageAdapter(getActivity(),new ArrayList<String>()); 

     gridView.setAdapter(imageAdapter); 

     gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() { 
      @Override 
      public void onItemClick(AdapterView<?> parent, View view, int position, long id) { 
       Log.v("check","ok"); 
      } 
     }); 

     return inflater.inflate(R.layout.fragment_main, container, false); 
    } 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 


    } 

    @Override 
    public void onStart() { 
     super.onStart(); 
     updateMovies(); 
    } 

    public void updateMovies() { 
     FetchMovieTask movieTask = new FetchMovieTask(); 
     movieTask.execute(); 
    } 

    public class FetchMovieTask extends AsyncTask<String, Void, String[]> { 


     final String LOG_TAG = FetchMovieTask.class.getSimpleName(); 

     private String[] getMovieImageFromJson(String movieJsonStr) 
       throws JSONException { 

      ArrayList<String> movieResults = new ArrayList<>(); 
      String posterUrl; 
      final String OWM_MOVIE_RESULTS = "results"; 
      JSONObject jsonObject = new JSONObject(movieJsonStr); 
      if (jsonObject.has(OWM_MOVIE_RESULTS)) { 
       JSONArray movieArray = jsonObject.getJSONArray(OWM_MOVIE_RESULTS); 

       //JSONArray movieArray = jsonObject.getJSONArray(OWM_MOVIE_RESULTS); 

       for (int i = 0; i < movieArray.length(); i++) { 
        JSONObject movieObject = movieArray.getJSONObject(i); 
        posterUrl = movieObject.getString("poster_path"); 
        movieResults.add(posterUrl); 
        Log.v(LOG_TAG, posterUrl); 
       } 
       for (String items : movieResults){ 
        Log.v(LOG_TAG,items); 
       } 



       // return null; 
      } 

      return movieResults.toArray(new String[0]); 



      // Log.v(LOG_TAG,posterUrl); 


     } 


     @Override 
     protected String[] doInBackground(String... params) { 


      HttpURLConnection urlConnection = null; 
      BufferedReader reader = null; 


      String movieJsonStr = null; 
      //parameters for api link will be here 

      try { 

       final String MOVIE_BASE_URL = "https://api.themoviedb.org/3/movie"; 
       final String APPID_PARAM = "api_key"; 
       final String CRITERIA_FOR_MOVIE_SELECTION_TOP = "top_rated"; 
       final String CRITERIA_FOR_MOVIE_SELECTION_POPULAR = "popular"; 



       Uri builtUri = Uri.parse(MOVIE_BASE_URL).buildUpon() 
         .appendPath(CRITERIA_FOR_MOVIE_SELECTION_TOP) 
         .appendQueryParameter(APPID_PARAM, BuildConfig.OPEN_MOVIEDB_API_KEY) 
         .build(); 

       Log.v("TAG","BuiltURI" + builtUri.toString()); 

       URL url = new URL(builtUri.toString()); 

       urlConnection = (HttpURLConnection) url.openConnection(); 
       urlConnection.setRequestMethod("GET"); 
       urlConnection.connect(); 

       // Read input stream into a String 

       InputStream inputstream = urlConnection.getInputStream(); 
       StringBuffer buffer = new StringBuffer(); 
       if (inputstream == null) { 

        movieJsonStr = null; 
       } 
       reader = new BufferedReader(new InputStreamReader(inputstream)); 

       String line; 
       while ((line = reader.readLine()) != null) { 
        buffer.append(line + "\n"); 
       } 

       if (buffer.length() == 0) { 
        movieJsonStr = null; 
       } 

       movieJsonStr = buffer.toString(); 

       Log.v(LOG_TAG, "Movie Json String" + movieJsonStr); 


      } catch (IOException e) { 
       Log.e(LOG_TAG, "error here" + e); 

       movieJsonStr = null; 
      } finally { 
       if (urlConnection != null) { 
        urlConnection.disconnect(); 
       } 
       if (reader != null) { 
        try { 
         reader.close(); 
        } catch (final IOException e) { 
         Log.e(LOG_TAG, "ErrorClosingStream", e); 
        } 
       } 


      } 

      try { 
       // here will be method call for JSon parsing. 
       String [] check_items = getMovieImageFromJson(movieJsonStr); 

       for (String items : check_items){ 
        Log.v(LOG_TAG,items+"new"); 
       } 
       return check_items; 

      } catch (JSONException e) { 
       Log.e(LOG_TAG, e.getMessage(), e); 
       e.printStackTrace(); 
      } 
      return null; 

     } 

     @Override 
     protected void onPostExecute(String[] result) { 

      if (result != null) { 


       for (String resultItems : result){ 
        Log.v(LOG_TAG,resultItems+"GoodLuck"); 
        final String PICTURE_BASE_URL = "http://image.tmdb.org/t/p/w185/"; 
        final String PICTURE_URL_END = resultItems; 
        Uri builtUri = Uri.parse(PICTURE_BASE_URL).buildUpon() 
          .appendPath(PICTURE_URL_END.replace("/","")) 
          .build(); 
        Log.v(LOG_TAG,resultItems+"GoodLuck"+builtUri.toString()); 
        imageAdapter.setmresultItems(builtUri.toString()); 
       } 
      } 
     } 

    } 
} 



class ImageAdapter extends BaseAdapter { 

     private Context mContext; 
     private ArrayList<String> mresultItems; 




     public ImageAdapter(Context c,ArrayList<String> resultItems){ 
      mContext = c; 
      mresultItems = resultItems; 

     } 

     public int getCount(){ 
      // return mThumbsIds.length; 
      return 0; 
     } 

     public Object getItem(int position){ 
      return null; 
     } 

     public long getItemId(int position){ 
      return 0; 
     } 


    public void setmresultItems(String resultItems){ 
       mresultItems.add(resultItems); 


    } 

     @Override 
     public View getView(int position, View convertView, ViewGroup parent) { 
      ImageView imageView; 

      if (convertView == null){ 
//   if it is not recycled, initialize some attributes 
       imageView = new ImageView(mContext); 
       imageView.setLayoutParams(new GridView.LayoutParams(85,85)); 
       imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); 
       imageView.setPadding(8,8,8,8); 

      }else{ 
       imageView = (ImageView) convertView; 
      } 
      //imageView.setImageResource(mThumbsIds[position]); 
      for(String picResultUrl : mresultItems){ 
       Picasso.with(mContext).load(picResultUrl).into(imageView); 


      } 


      return imageView; 
     } 



     //references to our Images 

     //private Integer[] mThumbsIds ; 





}** 

Answer 1

Sie haben nicht eine for-Schleife in der getView() -Methode erhalten, wird es bereits genannt für jedes Element in der Liste.

Seien Sie sicher, dass die richtige Anzahl zurück:

public int getCount(){ 
     return mresultItems.size(); 
    } 

Verwenden Sie dann nur die aktuelle Position der Datenquelle in getView():

@Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     ImageView imageView; 

     if (convertView == null){ 
      imageView = new ImageView(mContext); 
      imageView.setLayoutParams(new GridView.LayoutParams(85,85)); 
      imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); 
      imageView.setPadding(8,8,8,8); 

     }else{ 
      imageView = (ImageView) convertView; 
     } 

     //modified: 
     String picUrl = mresultItems.get(position); 
     Picasso.with(mContext).load(picUrl).into(imageView); 
     } 

     return imageView; 
    } 

, rufen auch notifyDataSetChanged() auf dem Adapter in onPostExecute(), nachdem die Datenquelle des Adapters aktualisiert wurde:

Answer 2

Ich habe festgestellt, dass ich die Ansicht in der onCreate-Methode, die die Ursache für einen leeren Bildschirm war, nicht zurückgab.