Question

我有一个通过拍照填充的ListView。每次我拍照时，照片都会作为ImageView条目添加到列表视图中，连同日期等。拍摄照片时，Uri会被保存到内存中的arraylist中，当显示列表视图时，它会加载从arraylist uris到bitmaps（按比例缩小）的行的图像，然后是imageview的drawables。一切正常，但是，当listview变得更长时，它变得非常慢，有时我会因字节分配错误而内存不足。

这是我在自己的自定义适配器中填充listview视图的地方：

public View getView(int position, View convertView, ViewGroup parent)
    {
        Uri selectedImage2 = Uri.parse(sampleuris.get(position).toString());

        Bitmap ThumbImage = null;

        if(convertView == null)
        {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView  = inflater.inflate(R.layout.row_list_sample_entry, parent , false);

        }

        ImageView sampleimage   = (ImageView)     convertView.findViewById(R.id.sampleimage);

        if(ThumbImage == null)
        {

             try
              {
                  ThumbImage = ThumbnailUtils.extractThumbnail(decodeUri(selectedImage2), 100, 100);
              }
              catch (FileNotFoundException ex)
              {
                  Logger.getLogger(Screen_View_Package.class.getName()).log(Level.SEVERE, null, ex);
              }

             Drawable d = new BitmapDrawable(null, ThumbImage);
             sampleimage.setImageDrawable(d);
        }
        else
        {
            Drawable d = new BitmapDrawable(null, ThumbImage);
            sampleimage.setImageDrawable(d);
        }

            TextView position2      = (TextView)      convertView.findViewById(R.id.packageimage2);
            TextView datereceived   = (TextView)      convertView.findViewById(R.id.date);


            position2.setText(""+(position+1));
            datereceived.setText(sampledates.get(position));
            //textSynced.setText("Synced: "+syncs.get(position));



            return convertView;
      }
    //----------------------------------------

Answer 1

我通过在listview填充之前将位图图像转换为字节数组来解决问题，然后对于listview，我只使用存储在内存中的bytearray来创建drawable并显示它们。没有内存错误。下面是listview的getview的新代码：

public View getView(int position, View convertView, ViewGroup parent)
    {
        //Uri selectedImage2 = Uri.parse(sampleuris.get(position).toString());

        //Bitmap ThumbImage = null;

        if(convertView == null)
        {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView  = inflater.inflate(R.layout.row_list_sample_entry, parent , false);

        }

        ImageView sampleimage   = (ImageView)     convertView.findViewById(R.id.sampleimage);

        byte[] b = Base64.decode(sampleuris.get(position),Base64.DEFAULT);
        ByteArrayInputStream is = new ByteArrayInputStream(b);
        Drawable d = Drawable.createFromStream(is, "bloodsample");
        sampleimage.setImageDrawable(d);

            TextView position2      = (TextView)      convertView.findViewById(R.id.packageimage2);
            TextView datereceived   = (TextView)      convertView.findViewById(R.id.date);


            position2.setText(""+(position+1));
            datereceived.setText(sampledates.get(position));
            //textSynced.setText("Synced: "+syncs.get(position));



            return convertView;
      }

listview ImageView性能缓慢

1 个答案: