如何實現視圖座插入陣列適配器

Question

* 更新* 嗨我解決我的問題我自己，我用的https://github.com/koush/UrlImageViewHelper/blob/master/README.md 並通過UrlImageViewHelper.setUrlDrawable（圖像，ei.img_url）;從我的Entryadapter類，它運作良好。

我想顯示Listview與3文本和一個imageview與分隔符/節列表中。 所以我按照這個教程http://bartinger.at/listview-with-sectionsseparators/？

比我面對加載圖像（位圖）的問題，所以我使用文件和bitmapfactory通過使用AsyncTask在列表視圖上顯示位圖。

但問題是它加載每次當我向上或向下滾動。我想要顯示列表一次，所以我想實現查看持有人爲我的列表，但因爲我更新的Android和Java我不知道我怎麼能實現這個我的代碼。

任何人都可以幫助我嗎？我附上了所有的代碼文件，所以這段代碼會幫助像我這樣的其他學生和新手。

這裏是我的Entryadaptor.java

public class EntryAdapter extends ArrayAdapter<Item> { 
private Context context; 
private ArrayList<Item> items; 
private LayoutInflater vi; 
Uri myurl; 
ImageView image; 
public EntryAdapter(Context context,ArrayList<Item> items) { 
    super(context,0, items); 
    this.context = context; 
    this.items = items; 
    vi = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
} 
@Override 
public View getView(int position, View convertView, ViewGroup parent) { 
    View v = convertView; 
    final Item i = items.get(position); 
    if (i != null) { 
     if(i.isSection()){ 
      SectionItem si = (SectionItem)i; 
      v = vi.inflate(R.layout.list_item_section, null); 
      v.setOnClickListener(null); 
      v.setOnLongClickListener(null); 
      v.setLongClickable(false); 
      final TextView sectionView = (TextView) v.findViewById(R.id.list_item_section_text); 
      sectionView.setText(si.getTitle()); 
     }else 
      { 
      EntryItem ei = (EntryItem)i; 
      v = vi.inflate(R.layout.list_item_entry, null); 
      final TextView title = (TextView)v.findViewById(R.id.list_item_entry_title); 
      final TextView subtitle = (TextView)v.findViewById(R.id.list_item_entry_summary); 
      image = (ImageView)v.findViewById(R.id.showlist_item_entry_drawable); 
      if (title != null) 
       title.setText(ei.title); 
      if(subtitle != null) 
       subtitle.setText(ei.subtitle); 
       if(image !=null) 
       { 
       try { 
         URL onLineURL = new URL(ei.img_url); 
         new MyNetworkTask(image).execute(onLineURL); 
         } catch (MalformedURLException e) { 
         e.printStackTrace(); 
         }}}} 
    return v; 
    } 
    private class MyNetworkTask extends AsyncTask<URL, Void, Bitmap>{ 
     ImageView tIV; 
     public MyNetworkTask(ImageView iv){ 
      tIV = iv; 
     } 
     @Override 
     protected Bitmap doInBackground(URL... urls) { 
     Bitmap networkBitmap = null; 
     URL networkUrl = urls[0]; //Load the first element 
     try { 
     networkBitmap = BitmapFactory.decodeStream(
      networkUrl.openConnection().getInputStream()); 
     } catch (IOException e) { 
     e.printStackTrace(); 
     } 
     return networkBitmap; 
     } 
     @Override 
     protected void onPostExecute(Bitmap result) { 
     tIV.setImageBitmap(result); 
     } 
     } 

}

這裏是片段代碼

public class ShowsFragment extends SherlockListFragment { ArrayList<Item> items = new ArrayList<Item>(); 
@Override 
public void onActivityCreated(Bundle savedInstanceState) { 
    super.onActivityCreated(savedInstanceState); 
    items.add(new SectionItem("Today")); 
     items.add(new EntryItem("Item 1", "This is item 1.2","http://pierre.chachatelier.fr/programmation/images/mozodojo-original-image.jpg")); 
     items.add(new EntryItem("Item 2", "This is item 1.3","http://upload.wikimedia.org/wikipedia/commons/8/85/Image-New_Delhi_Lotus.jpg")); 
     items.add(new SectionItem("This Week")); 
     items.add(new EntryItem("Item 4", "This is item 2.1","https://twimg0-a.akamaihd.net/profile_images/1080041262/VMIX_logo_zoom_bkbg1_normal.png")); EntryAdapter adapter = new EntryAdapter(getActivity(), items); 
     setListAdapter(adapter); 
    } 
    public void onListItemClick(ListView l, View v, int position, long id) { 
     if(!items.get(position).isSection()){ 
      EntryItem item = (EntryItem)items.get(position); 
      Toast.makeText(getActivity(), "You clicked " + item.title , Toast.LENGTH_SHORT).show(); 
     } 
     super.onListItemClick(l, v, position, id); 
    } 
} 

sectionItem代碼

public class SectionItem implements Item{ 
private final String title; 
public SectionItem(String title) { 
    this.title = title; 
} 
public String getTitle(){ 
    return title; 
} 
public boolean isSection() { 
    return true; 
} 

}

入境的物品類別代碼

public class EntryItem implements Item{ 
public final String title; 
public final String subtitle; 
public final String img_url; 
public EntryItem(String title, String subtitle,String Image_url) { 
    this.title = title; 
    this.subtitle = subtitle; 
    this.img_url = Image_url; 
} 
public boolean isSection() { 
    return false; 
} 

}

Answer 1

我建議某處緩存加載的位圖，這樣就可以避免服務器調用，如果你（使用地圖爲例）向上和向下滾動。 此外，由於您正在異步加載位圖，因此一旦您加載了數據，請確保視圖仍然是將圖像設置爲正確的視圖，因爲視圖在Listview中被循環（因此名稱爲「convertView」）。例如

if (item.equals(imageView.getTag())) { 
     // only set image if Tag is still valid 
     imageView.setImageDrawable(drawable); 
    } 

Answer 2

嘿傢伙就在今年的lib到您的項目，並通過圖像視圖對象和網址，並完成了對KoljaTM https://github.com/koush/UrlImageViewHelper/blob/master/README.md

Answer 3

大拇指。它解決了我的類似問題。我使用線程來加速gridview和我有問題，一些圖片位置混合海誓山盟。採用KoljaTM的方法後，沒有發生扭曲。謝謝。