ListView的內容佔用大量內存

Question

ListView包含相當多的項目（20個或更多），並且它們中的每一個都是帶有位圖源的ImageView。這些位圖不被壓縮，尺寸大約爲640x480。當剛加載ListView時，需要一些內存，但如果我滾動它，則可能會發生錯誤"Memory exceed VM budjet"。當我用另一個片段替換片段時，ListView仍然掛在內存中。我如何清除內存/ ListView緩存？

更新：在一個單獨的線程

SimpleCursorAdapter.ViewBinder viewBinder = new SimpleCursorAdapter.ViewBinder() { 
     public boolean setViewValue(View view, Cursor cursor, int columnIndex) { 
      if (columnIndex == 0) { 
       TextView tv1 = (TextView) view; 
       if (cursor.getInt(4) == 0) 
        tv1.setTextColor(Color.GRAY); 
       else 
        tv1.setTextColor(Color.parseColor("#191919")); 
       tv1.setText(cursor.getString(columnIndex)); 
      } 
      if (columnIndex == 3) { 
       TextView tv1 = (TextView) view; 
       tv1.setText(cursor.getString(columnIndex)); 
      } 
      if (columnIndex == 2) { 
       final ImageView image = (ImageView) view; 
       Bitmap cachedImage = null; 
       try { 
        cachedImage = imageThreadLoader.loadImage(cursor.getString(columnIndex), new ImageThreadLoader.ImageLoadedListener() { 
         public void imageLoaded(Bitmap imageBitmap) { 
          image.setImageBitmap((Bitmap) new SoftReference(imageBitmap).get()); 
         } 
        }); 
       } catch (MalformedURLException mue) { 
        Log.e("Feeds fragment", "Can't load image"); 
       } 
       if (cachedImage != null) { 
        image.setImageBitmap(cachedImage); 
       } else image.setImageDrawable(getResources().getDrawable(R.drawable.icon)); 
      } 

圖片負荷：

我使用SimpleCursorAdapter與ViewBinder。

Answer 1

構建這樣的列表視圖使您自定義適配器，並將其設置到ListView

public class InteractiveArrayAdapter extends ArrayAdapter<Model> { 

    private final List<Model> list; 
    private final Activity context; 

    public InteractiveArrayAdapter(Activity context, List<Model> list) { 
     super(context, R.layout.main, list); 
     this.context = context; 
     this.list = list; 
    } 

    static class ViewHolder { 
     protected TextView text; 
     protected CheckBox checkbox; 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     View view = null; 
     if (convertView == null) { 
      LayoutInflater inflator = context.getLayoutInflater(); 
      view = inflator.inflate(R.layout.main, null); 
      final ViewHolder viewHolder = new ViewHolder(); 
      viewHolder.text = (TextView) view.findViewById(R.id.listitem_text); 
      viewHolder.checkbox = (CheckBox) view.findViewById(R.id.checkBox1); 
      viewHolder.checkbox 
        .setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { 

         public void onCheckedChanged(CompoundButton buttonView, 
           boolean isChecked) { 
          Model element = (Model) viewHolder.checkbox 
            .getTag(); 
          element.setSelected(buttonView.isChecked()); 

         } 
        }); 
      view.setTag(viewHolder); 
      viewHolder.checkbox.setTag(list.get(position)); 
     } else { 
      view = convertView; 
      ((ViewHolder) view.getTag()).checkbox.setTag(list.get(position)); 
     } 
     ViewHolder holder = (ViewHolder) view.getTag(); 
     holder.text.setText(list.get(position).getName()); 
     holder.checkbox.setChecked(list.get(position).isSelected()); 
     return view; 
    } 
} 

嘗試這種方式，你的不必要的視圖將被回收和excecution將更快，希望你將擺脫錯誤

Answer 2

我建議您觀看關於ListViews的Google IO presentation。它包含了內存保存技術，它幫助我理解了ListView的邏輯。