Question

当我运行此代码时，我在Input stream in =url.openstream上收到错误帮我。解决这个问题

我在清单

中添加了互联网和写入和读取权限

我在createmethod上创建了一个 asyncktask 的实例我在url.openstream中尝试doInbackground但仍然收到错误

没有我在Java程序中执行的asyncktask类。但在Android无法正常工作

 private class Mine extends AsyncTask<Void,Void,Void>
{
    @Override
    protected void onPreExecute() {
        Toast.makeText(getApplicationContext(),"its loading",Toast.LENGTH_LONG).show();
        super.onPreExecute();
    }

    @Override
    protected Void doInBackground(Void... params) {


        try {
            Document doc=Jsoup.connect(addr).get();
            come=doc.title();
            Elements image=doc.getElementsByTag("img");

            for(Element thereimage:image)
            {
                thereimagelink=thereimage.attr("abs:src");
            }
            int indexname = thereimagelink.lastIndexOf("/");

            if(indexname==thereimagelink.length())
            {
                thereimagelink=thereimagelink.substring(1,indexname);
            }
            indexname = thereimagelink.lastIndexOf("/");
            hereimagename=thereimagelink.substring(indexname,thereimagelink.length());







        } catch (IOException e) {
            e.printStackTrace();
        }
        //Toast.makeText(getApplicationContext(),""+come,Toast.LENGTH_SHORT).show();
        return null;
    }

    @Override
    protected void onPostExecute(Void aVoid) {

        try {

            URL url=new URL(thereimagelink);
            InputStream in=url.openStream();

            OutputStream out=new BufferedOutputStream(new FileOutputStream(folder+hereimagename));
            for (int b; (b = in.read()) != -1;) {

                out.write(b);

            }
            out.close();

            in.close();

        }catch (IOException e)
        {

        }
        Toast.makeText(getApplicationContext(),"its finishd",Toast.LENGTH_LONG).show();




        super.onPostExecute(aVoid);
    }

Answer 1

您在url.openStream()中运行onPostExecute()，它在UI线程上运行。 Android要求所有网络操作都应该在后台线程中进行，因此所有这些操作都应该在doInBackground()

中进行

如何使用url.openstream？

1 个答案: