由于异步任务，ImageView 在我的列表视图中不断移动

Question

嗨，我的问题很简单：图像视图未修复。我在此链接中看到了答案：链接，我确实理解答案，但我可以不要这样做。所以我的问题是：如何关闭适配器中的视图回收？

如果你愿意，我可以添加一些代码：

public class PortfolioAdapter extends ArrayAdapter<PortfolioView>{
private ArrayList<PortfolioView> items;
public PortfolioAdapter(Context context, int textViewResourceId, ArrayList<PortfolioView> items) {
    super(context, textViewResourceId, items);
    this.items = items;
}
public View getView(int position, View convertView, ViewGroup parent) {
    View v = convertView;
    if (v == null) {
        LayoutInflater vi = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        v = vi.inflate(R.layout.portfolio_rows, null);
    }
    PortfolioView pv = items.get(position);
    if (pv != null) {
            TextView ticker = (TextView) v.findViewById(R.id.portfolio_rows_ticker);
            TextView location = (TextView)v.findViewById(R.id.portfolio_rows_location);
            TextView country = (TextView)v.findViewById(R.id.portfolio_rows_country);
            TextView portfolio_value = (TextView)v.findViewById(R.id.portfolio_rows_portfolio_value);
            TextView yesterday_earnings = (TextView)v.findViewById(R.id.portfolio_rows_yesterday_earnings);
            TextView shares = (TextView)v.findViewById(R.id.portfolio_rows_shares);
            TextView last_buy_shares = (TextView)v.findViewById(R.id.portfolio_rows_last_buy_shares);
            TextView last_buy = (TextView)v.findViewById(R.id.portfolio_rows_last_buy);
            TextView your_shares_held = (TextView)v.findViewById(R.id.portfolio_rows_your_shares_held);
            ImageView SmPortrait = (ImageView)v.findViewById(R.id.portfolio_rows_sm_portrait);
            if (ticker != null) {
                  ticker.setText(pv.getPortfolio_ticker()); 
            }
            if (location != null) {
                location.setText(pv.getLocation()); 
            }
            if (country != null) {
                country.setText(pv.getCountry()); 
            }
            if (portfolio_value != null) {
                DecimalFormat f_portfolio_value = new DecimalFormat();
                f_portfolio_value.setMaximumFractionDigits(2);
                String portfolio_value_format = f_portfolio_value.format(pv.getPortfolio_value());

                portfolio_value.setText(portfolio_value_format); 
            }
            if (yesterday_earnings != null) {
                DecimalFormat f_yesterday_earnings = new DecimalFormat();
                f_yesterday_earnings.setMaximumFractionDigits(2);
                String yesterday_earnings_format = f_yesterday_earnings.format(pv.getYesterday_earnings());

                yesterday_earnings.setText(yesterday_earnings_format); 
            }
            if (shares != null) {
                shares.setText(Integer.toString(pv.getShares())); 
            }
            if (last_buy_shares != null) {
                last_buy_shares.setText(Integer.toString(pv.getLast_buy_shares())); 
            }
            if (last_buy != null) {
                last_buy.setText(pv.getLast_buy()); 
            }
            if (your_shares_held != null) {
                your_shares_held.setText(Integer.toString(pv.getYour_shares_held())); 
            }
            if(SmPortrait != null){
                createimage(SmPortrait, pv.getSm_portrait());
            }

    }
    return v;
}
private class CreateImage extends AsyncTask<String, Void, Drawable> {
    ImageView image;
    public CreateImage(ImageView img) {
        image = img;
        image.invalidate();
    }
    protected void onPreExecute() {
    }

    protected Drawable doInBackground(String... urls) {
        InputStream is;
        Drawable d = null ;
        try {
            is = (InputStream)new URL(urls[0]).getContent();
            d = Drawable.createFromStream(is, "Image");
            return d;
        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return d;
    }
    protected void onPostExecute(Drawable d) {
        image.setBackgroundDrawable(d);
        image.invalidateDrawable(d);

    }
}
// Catch portrait
public void createimage(ImageView img, String url){
    new CreateImage(img).execute(url);
}

}

Answer 1

基本思想是，当您设置视图时，您想要添加缩略图作为占位符。然后使用 Tag 属性用数据库中的 ID 之类的东西“标记”视图 - 然后可以使用它来识别哪一行应该获取图像，并且您不应该再遭受移动行的困扰。

看看 Fedor 对这个问题的回答：链接 - 它为您提供了一个非常好的示例。

Answer 2

设置背景后，您不需要使可绘制图像无效。 删除行并查看是否修复。

image.invalidateDrawable(d);

从 onPostExecute() 方法中

Answer 3

ImageView 类的 invalidateDrawable 方法是什么？

我找到了如下的源码核心：

@Override
public void invalidateDrawable(Drawable dr) {
    if (dr == mDrawable) {
        /* we invalidate the whole view in this case because it's very
         * hard to know where the drawable actually is. This is made
         * complicated because of the offsets and transformations that
         * can be applied. In theory we could get the drawable's bounds
         * and run them through the transformation and offsets, but this
         * is probably not worth the effort.
         */
        invalidate();
    } else {
        super.invalidateDrawable(dr);
    }
}