如何从Recycler View适配器类打开任何类型的文件？

Question

What i'm trying to do is when the file is successfully downloaded it should be automatically opened from the file path but now here the problem is that i need to fire the path from my recycler view adapter class when i try to do that it generates an exception Take a look at my adapter class: Here i'm using a class with the adapter which will basically download the file from the url but when i try to fire the intent for opening the file from download class it just goes to error something went wrong.

public class Filelistadapter extends RecyclerView.Adapter<Filelistadapter.ProjectViewHolder>{
    private String url;

    private ArrayList<Taskmsg> dataList;


    Context mContext;


    public Filelistadapter(ArrayList<Taskmsg> dataList, Context mContext) {
        this.dataList = dataList;
        this.mContext=mContext;

    }

    @Override
    public ProjectViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
        View view = layoutInflater.inflate(R.layout.file_item, parent, false);
        return new ProjectViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ProjectViewHolder holder, int position) {
        String fname=dataList.get(position).getFilename();
        holder.txtfilename.setText(fname);
        holder.download.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                url="http://pms.cloudester.com/task_doc/"+fname;
                new DownloadFile().execute(url);

            }
        });


    }



    @Override
    public int getItemCount() {

        return dataList.size();

    }

    class ProjectViewHolder extends RecyclerView.ViewHolder {

        TextView txtfilename;
        Button download;
        ProjectViewHolder(View itemView) {
            super(itemView);
            txtfilename = (TextView) itemView.findViewById(R.id.tvfilename);
            download=itemView.findViewById(R.id.actionButton);

        }
    }

    private class DownloadFile extends AsyncTask<String, String, String> {

        private ProgressDialog progressDialog;
        private String fileName;
        private String folder;
        private boolean isDownloaded;

        /**
         * Before starting background thread
         * Show Progress Bar Dialog
         */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            this.progressDialog = new ProgressDialog(mContext);
            this.progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            this.progressDialog.setCancelable(false);
            this.progressDialog.show();
        }

        /**
         * Downloading file in background thread
         */
        @Override
        protected String doInBackground(String... f_url) {
            int count;
            try {
                URL url = new URL(f_url[0]);
                URLConnection connection = url.openConnection();
                connection.connect();
                // getting file length
                int lengthOfFile = connection.getContentLength();


                // input stream to read file - with 8k buffer
                InputStream input = new BufferedInputStream(url.openStream(), 8192);

                String timestamp = new SimpleDateFormat("yyyy.MM.dd.HH.mm.ss").format(new Date());

                //Extract file name from URL
                fileName = f_url[0].substring(f_url[0].lastIndexOf('/') + 1, f_url[0].length());

                //Append timestamp to file name
                fileName = timestamp + "_" + fileName;

                //External directory path to save file
                folder = Environment.getExternalStorageDirectory() + File.separator + "pms/";

                //Create androiddeft folder if it does not exist
                File directory = new File(folder);

                if (!directory.exists()) {
                    directory.mkdirs();
                }

                // Output stream to write file
                OutputStream output = new FileOutputStream(folder + fileName);

                byte data[] = new byte[1024];

                long total = 0;

                while ((count = input.read(data)) != -1) {
                    total += count;
                    // publishing the progress....
                    // After this onProgressUpdate will be called
                    publishProgress("" + (int) ((total * 100) / lengthOfFile));


                    // writing data to file
                    output.write(data, 0, count);
                }

                // flushing output
                output.flush();

                // closing streams
                output.close();
                input.close();
                return "Downloaded at: " + folder + fileName;
            } catch (Exception e) {
                Log.e("Error: ", e.getMessage());
            }
            return "Something went wrong";
        }

        /**
         * Updating progress bar
         */
        protected void onProgressUpdate(String... progress) {
            // setting progress percentage
            progressDialog.setProgress(Integer.parseInt(progress[0]));
        }


        @Override
        protected void onPostExecute(String message) {
            // dismiss the dialog after the file was downloaded
            this.progressDialog.dismiss();

            // Display File path after downloading
            Toast.makeText(mContext,
                    message, Toast.LENGTH_LONG).show();
        }
    }
}

Answer 1

You have two errors

Do this inside button click or else you will get the name of last postion always

String fname=dataList.get(position).getFilename();

And Do this in post execute method change type as you want

Intent testIntent = new Intent();
    testIntent.setType("application/pdf");
    testIntent.setAction(Intent.ACTION_VIEW);
    Uri uri = Uri.fromFile(folder+filename);
    testIntent.setDataAndType(uri, "application/pdf");
    startActivity(testIntent);