Afficher les images GridView de JSON Android

Question

J'ai un problème lors de l'affichage des images de JSON à GridView pourrait m'aider.

GalleryActivity.java

public class GalleryActivity extends Activity { 

    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.gallery_layout); 

     Intent i = getIntent(); 

     String tempid = i.getStringExtra("tempid"); 

     GridView gridView = (GridView) findViewById(R.id.grid_view); 


     gridView.setAdapter(new ImageAdapter(this,tempid)); 


     gridView.setOnItemClickListener(new OnItemClickListener() { 

      public void onItemClick(AdapterView<?> parent, View v, 
        int position, long id) { 

      } 
     }); 
    } 
} 

ImageAdapter.java

public class ImageAdapter extends BaseAdapter { 
    private Context mContext; 

    public String[] mThumbIds; 

    private static String KEY_SUCCESS = "success"; 

    private static String KEY_IMAGES = "images"; 
    private static String KEY_IMAGE = "url_img"; 


    // Constructor 
    public ImageAdapter(Context c,String tempID){ 
     mContext = c; 
     final DealerFunctions dealerFunction = new DealerFunctions(); 
     JSONObject json = dealerFunction.getImages(tempID); 

     try { 

       if (json.getString(KEY_SUCCESS) != null) { 

        String res = json.getString(KEY_SUCCESS); 
        if (Integer.parseInt(res) == 1) { 


         JSONArray imagesFields = json 
           .getJSONArray(KEY_IMAGES); 


         for (int i = 0; i < imagesFields.length(); i++) { 
          JSONObject x = imagesFields.getJSONObject(i); 

          mThumbIds[i] = x.getString(KEY_IMAGE); 


         } 



        } else { 


        } 

       } 
      } catch (JSONException e) { 
       e.printStackTrace(); 
      } 

    } 


    public int getCount() { 
     return mThumbIds.length; 
    } 


    public Object getItem(int position) { 
     return mThumbIds[position]; 
    } 


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


    public View getView(int position, View convertView, ViewGroup parent) {   
     ImageView imageView; 
     if (convertView==null){ 

      imageView = new ImageView(mContext); 
      imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); 
      imageView.setLayoutParams(new GridView.LayoutParams(70, 70)); 

     }else{ 
      imageView = (ImageView) convertView; 
     } 

     imageView.setBackgroundDrawable(Drawable.createFromPath(mThumbIds[position])); 

     return imageView; 
    } 

} 

ne fonctionnent pas ...

quand je lance l'application, ferme immédiatement supposer que le problème vient imageView .setBackgroundDrawable (Drawable.createFromPath (mThumbIds [position]));

Je besoin de votre aide gars

erreurs LogCat comme suit.

03-27 10:50:12.658: D/AndroidRuntime(1782): Shutting down VM 
03-27 10:50:12.658: W/dalvikvm(1782): threadid=1: thread exiting with uncaught exception (group=0x4001d800) 
03-27 10:50:12.678: E/AndroidRuntime(1782): FATAL EXCEPTION: main 
03-27 10:50:12.678: E/AndroidRuntime(1782): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.montalvo.dealer/com.montalvo.dealer.GalleryActivity}: java.lang.NullPointerException 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at android.app.ActivityThread.access$2300(ActivityThread.java:125) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at android.os.Handler.dispatchMessage(Handler.java:99) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at android.os.Looper.loop(Looper.java:123) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at android.app.ActivityThread.main(ActivityThread.java:4627) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at java.lang.reflect.Method.invokeNative(Native Method) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at java.lang.reflect.Method.invoke(Method.java:521) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at dalvik.system.NativeStart.main(Native Method) 
03-27 10:50:12.678: E/AndroidRuntime(1782): Caused by: java.lang.NullPointerException 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at com.montalvo.dealer.ImageAdapter.<init>(ImageAdapter.java:57) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at com.montalvo.dealer.GalleryActivity.onCreate(GalleryActivity.java:25) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 
03-27 10:50:12.678: E/AndroidRuntime(1782):  ... 11 more 
03-27 10:50:15.501: I/Process(1782): Sending signal. PID: 1782 SIG: 9 

Answer 1

Vous confondez les choses ici, utilisez ce

public View getView(int position, View convertView, ViewGroup parent) {   
    ImageView imageView; 
    imageView = new ImageView(mContext); 
    imageView.setScaleType(ImageView.ScaleType.CENTER_CROP); 
    imageView.setLayoutParams(new GridView.LayoutParams(70, 70)); 


    imageView.setBackgroundDrawable(Drawable.createFromPath(mThumbIds[position])); 

    return imageView; 
} 

Le modèle que vous avez utilisé est celui de la ViewHolder mais vous n'êtes pas en train de créer des vues. Si vous voulez utiliser le modèle ViewHolder, puis

1. d'abord créer un fichier XML avec un ImageView.
2. Créez une classe ViewHolder dans votre ImageAdapter avec un ImageView.
3. Dans la méthode getView(), gonflez le fichier XML.
4. créer le viewholder pour le cas de convertview == null
5. Définissez le viewholder en tant que TAG de la vue de conversion.
6. dans l'autre condition, affectez le viewholder précédemment créé à la conversionview.