Android getView和ImageAdapter

Question

我想實現那種gallery，但與遠程獲取圖像的區別。 這個想法是僅在圖像下載完成後更新視圖。 =>我只需要在onComplete時更新視圖。

請在下面找到我的代碼：

public class displayAlbums extends Activity { 


    private static String URL_GRAPH_API = "https://graph.facebook.com/"; 
    private static final String TAG = "displayAlbums"; 
    private ArrayList<Bitmap> thumbnails = new ArrayList<Bitmap>(); 
    private ArrayList<URI> thumbnails_uri = new ArrayList<URI>(); 
    private ImageAdapter imageAdapter; 
    private int imageCounter = 0; 
    public boolean[] thumbnailsselection; 
    public Albums album; 
    private Context displayAlbums_context; 



    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.galleryitem); 
     this.displayAlbums_context = this; 
     Log.d(TAG, "on create");  
     findViewById(R.id.itemCheckBox).setVisibility(View.GONE); 
     final GridView imagegrid = (GridView) findViewById(R.id.PhoneImageGrid);   
     populateThumbnailsList(); 




     processThumbnailsToDownload(thumbnails_uri, new PictureRequestListener() { 

      @Override 
      public void onComplete(Bitmap bitmap) { 

       if(imageAdapter == null) { 
        Log.d(TAG, "image adapter is null"); 
        imageAdapter = new ImageAdapter(displayAlbums_context); 
        imagegrid.setAdapter(imageAdapter); 
       } 
       imagegrid.setId(imageCounter); 
       thumbnails.add(bitmap);  
       imageCounter++; 
       //imageAdapter.notifyDataSetChanged(); 
      } 
     }); 

    } 




    public void processThumbnailsToDownload(ArrayList<URI> thumbnails_uri, final FbRequestListener listener) {  
     Log.v(TAG,"processThumbnailsToDownload CALLED"); 
     for(URI thumbnail_uri : thumbnails_uri) { 
      new HttpConnection(ConnectionManager.getConnectionHandler(listener)).bitmap(thumbnail_uri); 
     } 
    } 



    public void populateThumbnailsList() { 
     URI uri = null; 

     for(final Albums album : LoadObjects.albums ) {  
      Bundle parameters = new Bundle(); 
      parameters.putString("access_token", FbpicturesActivity.mFacebook.getAccessToken());    
      try { 
       uri = new URI(URL_GRAPH_API + album.getAid() + "/picture" + "?" +Util.encodeUrl(parameters)); 
       thumbnails_uri.add(uri); 
      } catch (URISyntaxException e) { 
       e.printStackTrace(); 
      } 
     } 
    } 



public class ImageAdapter extends BaseAdapter { 


     private LayoutInflater mInflater; 
     private Context myContext; 

     public ImageAdapter(Context displayAlbums_context) { 
      Log.v(TAG,"IMAGE ADAPTER"); 
      mInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); 


     } 

     public int getCount() { 
      Log.d(TAG,"thumnail_uri size"+thumbnails_uri.size()); 
      return thumbnails_uri.size(); 
     } 

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

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

     public View getView(final int position, View convertView, ViewGroup parent) { 
      Log.v(TAG,"GET VIEW CALLED"); 
      ViewHolder holder; 
      if (convertView == null) { 
       holder = new ViewHolder(); 
       convertView = mInflater.inflate(R.layout.galleryitem, null); 
       holder.imageview = (ImageView) convertView.findViewById(R.id.thumbImage); 
       holder.checkbox = (CheckBox) convertView.findViewById(R.id.itemCheckBox);    
       convertView.setTag(holder); 
      } 
      else { 
       holder = (ViewHolder) convertView.getTag(); 
      } 





      //holder.checkbox.setId(position); 
      //holder.imageview.setId(position); 
      Log.d(TAG,"thumnail size"+thumbnails.size()); 
      Log.d(TAG,"thumnail position"+thumbnails.get(position)); 

      holder.imageview.setImageBitmap(thumbnails.get(position)); 
      holder.checkbox.setChecked(true); 
      holder.id = position; 

      return convertView; 


     } 
    } 

} 


class ViewHolder { 
    ImageView imageview; 
    CheckBox checkbox; 
    int id; 
} 

galleryItem.xml：

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" android:layout_height="fill_parent"> 
    <Button android:id="@+id/selectBtn" 
     android:layout_width="wrap_content" android:layout_height="wrap_content" 
     android:text="Select" android:layout_alignParentBottom="true" 
     android:layout_centerHorizontal="true" 
     android:minWidth="200px" /> 

    <GridView android:id="@+id/PhoneImageGrid" 
     android:layout_width="fill_parent" android:layout_height="fill_parent" 
     android:numColumns="auto_fit" android:verticalSpacing="10dp" 
     android:horizontalSpacing="10dp" android:columnWidth="90dp" 
     android:stretchMode="columnWidth" android:gravity="center" 
     android:layout_above="@id/selectBtn" /> 

    <ImageView android:id="@+id/thumbImage" android:layout_width="wrap_content" 
     android:layout_height="wrap_content" android:layout_centerInParent="true" /> 

    <CheckBox android:id="@+id/itemCheckBox" android:layout_width="wrap_content" 
     android:layout_height="wrap_content" android:layout_alignParentRight="true" 
     android:layout_alignParentTop="true" /> 

</RelativeLayout> 

請注意我添加了一些Log.v瞭解何時getView叫做：

=>http://pastebin.com/L9PYBYDa

問題：

1）爲什麼getView被調用4次？

2）爲什麼holder.imageview.setImageBitmap（thumbnails.get（position））返回java.lang.IndexOutOfBoundsException：索引1無效，大小爲1？

3）你有什麼建議來實現我的畫廊與遠程圖像？

非常感謝您的幫助

Answer 1

1）getView將至少調用（numberOfVisibleRows + 1或+2）次。我說至少是因爲它可以像系統想要的那樣被多次調用。這不能保證。

2）由於縮略圖小於2或爲空。你必須調試看到

3）檢查this出