変数を作成するにはどうすればいいですか？

Question

私は4つの方法でURLを取得し、Imageloaderがイメージを読み込みます。

画像はギャラリービュー内で設定されます。

問題は、画像が表示されていないときに画面が小さくなったときに、ユーザーがスワップバックしたときに再読み込みされることです。

HOwテストするものを作成し、画像が表示されていないときにイメージが再読み込みされないようにしますか？

ここに画像をロードするコードがあります。フルクラスです。

if(Build.VERSION.SDK_INT >= 11){ 
     StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build(); 
    StrictMode.setThreadPolicy(policy); 
    } 


    myGames.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      startActivity(n); 

     } 
    }); 
    gameNews.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View v) { 

     } 
    }); 

    //Executing AsyncTask in background thread to get game images. 
    MyTask myTask = new MyTask(); 

    myTask.execute(); 

} 
//Method to get images from text documents that will by updated every month. 


public void getImages() throws IOException{ 


    DefaultHttpClient httpclient = new DefaultHttpClient(); 

    HttpGet httppost = new HttpGet("https://sites.google.com/site/theitrangers/images/webImages.txt"); 
    HttpResponse response; 

     response = httpclient.execute(httppost); 


      HttpEntity ht = response.getEntity(); 

      BufferedHttpEntity buf = new BufferedHttpEntity(ht); 

      InputStream is = buf.getContent(); 


      BufferedReader r = new BufferedReader(new InputStreamReader(is)); 

      StringBuilder total = new StringBuilder(); 
      String line; 
      while ((line = r.readLine()) != null) { 
       total.append(line + "\n"); 

       imageUrl = total.toString(); 
       Log.v("getImage1", "Retreived image"); 
      } 
    } 



      public void getImage2() throws IOException{ 

       DefaultHttpClient httpclient = new DefaultHttpClient(); 

       HttpGet httppost = new HttpGet("https://sites.google.com/site/theitrangers/images/webImage2.txt"); 
       HttpResponse response; 


        response = httpclient.execute(httppost); 


         HttpEntity ht = response.getEntity(); 

         BufferedHttpEntity buf = new BufferedHttpEntity(ht); 

         InputStream is = buf.getContent(); 


         BufferedReader r = new BufferedReader(new InputStreamReader(is)); 

         StringBuilder total = new StringBuilder(); 
         String line; 
         while ((line = r.readLine()) != null) { 
          total.append(line + "\n"); 

          imageUrl2 = total.toString(); 
          Log.v("getImage2", "Retreived image"); 
         } 
       } 



         public void getImage3() throws IOException{ 

          DefaultHttpClient httpclient = new DefaultHttpClient(); 

          HttpGet httppost = new HttpGet("https://sites.google.com/site/theitrangers/images/webimage3.txt"); 
          HttpResponse response; 


           response = httpclient.execute(httppost); 


            HttpEntity ht = response.getEntity(); 

            BufferedHttpEntity buf = new BufferedHttpEntity(ht); 

            InputStream is = buf.getContent(); 


            BufferedReader r = new BufferedReader(new InputStreamReader(is)); 

            StringBuilder total = new StringBuilder(); 
            String line; 
            while ((line = r.readLine()) != null) { 
             total.append(line + "\n"); 

             imageUrl3 = total.toString(); 
             Log.v("getImage3", "Retreived image"); 
            } 

         } 

         public void getImage4() throws IOException{ 

          DefaultHttpClient httpclient = new DefaultHttpClient(); 

          HttpGet httppost = new HttpGet("https://sites.google.com/site/theitrangers/images/webImage4.txt"); 
          HttpResponse response; 


           response = httpclient.execute(httppost); 


            HttpEntity ht = response.getEntity(); 

            BufferedHttpEntity buf = new BufferedHttpEntity(ht); 

            InputStream is = buf.getContent(); 


            BufferedReader r = new BufferedReader(new InputStreamReader(is)); 

            StringBuilder total = new StringBuilder(); 
            String line; 
            while ((line = r.readLine()) != null) { 
             total.append(line + "\n"); 

             imageUrl4 = total.toString(); 


          } 
} 

         //ImageAdapter that gets the URL of the images and put them in a format to be set to gallery 
      public class ImageAdapter extends BaseAdapter { 
       /** The parent context */ 
       private Context myContext;public ImageAdapter() { 
        // TODO Auto-generated constructor stub 
       } 
       /** URL-Strings to some remote images. */ 

       public String[] myRemoteImages = {imageUrl,imageUrl2,imageUrl3,imageUrl4}; 






       /** Simple Constructor saving the 'parent' context. */ 
       public ImageAdapter(Context c) { this.myContext = c; } 





       /** Returns the amount of images we have defined. */ 
       public int getCount() { return this.myRemoteImages.length; } 

       /* Use the array-Positions as unique IDs */ 
       public Object getItem(int position) { return position; } 
       public long getItemId(int position) { return position; } 

       /** Returns a new ImageView to 
       * be displayed, depending on 
       * the position passed. */ 
       public View getView(int position, View convertView, ViewGroup parent) { 
       ImageView i = new ImageView(this.myContext); 

       try { 

           URL aURL = new URL(myRemoteImages[position]); 
           URLConnection conn = aURL.openConnection(); 

           conn.connect(); 

           InputStream is = conn.getInputStream(); 
           /* Buffered is always good for a performance plus. */ 
           BufferedInputStream bis = new BufferedInputStream(is); 
           /* Decode url-data to a bitmap. */ 

           Bitmap bm = BitmapFactory.decodeStream(bis); 
           bis.close(); 
           is.close(); 
           Log.v(imageUrl, "Retrieving image"); 

           /* Apply the Bitmap to the ImageView that will be returned. */ 
           i.setImageBitmap(bm); 
         } catch (IOException e) { 

           Log.e("DEBUGTAG", "Remtoe Image Exception", e); 
         } 

       /* Image should be scaled as width/height are set. */ 
       i.setScaleType(ImageView.ScaleType.FIT_CENTER); 
       /* Set the Width/Height of the ImageView. */ 
       i.setLayoutParams(new Gallery.LayoutParams(150, 150)); 
       return i; 
       } 

       /** Returns the size (0.0f to 1.0f) of the views 
       * depending on the 'offset' to the center. */ 
       public float getScale(boolean focused, int offset) { 
       /* Formula: 1/(2^offset) */ 
       return Math.max(0, 1.0f/(float)Math.pow(2, Math.abs(offset))); 
       } 
       } 





      //the important AsyncTask method. running the background thread to get the images and set them to the gallery. 
       private class MyTask extends AsyncTask<Void, Void, Void>{ 


       @Override 
       protected Void doInBackground(Void... arg0) {try { 
          getImages(); 
          Log.v("MyTask", "Image 1 retreived"); 
          getImage2(); 
          Log.v("MyTask", "Image 2 retreived"); 
          getImage3(); 
          Log.v("MyTask", "Image 3 retreived"); 
          getImage4(); 
          Log.v("MyTask", "Image 4 retreived"); 
         } catch (IOException e) { 
          Log.e("MainMenu retreive image", "Image Retreival failed"); 
          e.printStackTrace(); 
         } 
        return null; 
       } 
       @Override 

       protected void onPostExecute(Void notUsed){ 
        ((Gallery) findViewById(R.id.gallery)) 
          .setAdapter(new ImageAdapter(MainMenu.this)); 


       } 

         } 

}

Answer 1

それは再度ダウンロードする必要がないように、画像がすでにキャッシュに存在する場合、各画像のチェックのために、その後、キャッシュにそれらのフェッチされた画像を保存してみてください。