Android 如果Recyclerview滚动，则项目id更改如何解决？ public PDFListAdapter（上下文上下文、数组列表pdfModelClasses、字符串final_nav_opt_name）{ this.context=上下文； this.pd

如果Recyclerview滚动，则项目id更改如何解决？

public PDFListAdapter（上下文上下文、数组列表pdfModelClasses、字符串final_nav_opt_name）{
this.context=上下文；
this.pdfModelClasses=pdfModelClasses；
this.final_nav_opt_name=final_nav_opt_name；
databaseNotes=新的databaseNotes（上下文）；
}
公共类MyViewHolder扩展了RecyclerView.ViewHolder{
TextView txtBookName、txtBookTitle、txtBookBookDateOFIssue、txtBookCategory、txtDownload；
线性布局布局\打开\ pdf，布局\下载\注释\选项；
ImageView imgDownloadNote、imgCancelDownloadNote；
ProgressBar进度\下载\备注；
公共MyViewHolder（视图）{
超级（视图）；
txtBookName=（TextView）view.findViewById（R.id.txtBookName）；
txtBookTitle=（TextView）view.findViewById（R.id.txtBookTitle）；
txtBookBookDateOFIssue=（TextView）view.findViewById（R.id.txtBookBookDateOFIssue）；
txtBookCategory=（TextView）view.findViewById（R.id.txtBookCategory）；
txtDownload=view.findviewbyd（R.id.txtDownload）；
layout\u open\u pdf=（LinearLayout）view.findviewbyd（R.id.layout\u open\u pdf）；
布局下载注释选项=（LinearLayout）视图.findViewById（R.id.layout下载注释选项）；
imgDownloadNote=（ImageView）view.findViewById（R.id.imgDownloadNote）；
progress\u download\u note=（ProgressBar）view.findviewbyd（R.id.progress\u download\u note）；
imgCancelDownloadNote=（ImageView）view.findViewById（R.id.imgCancelDownloadNote）；
}
}
@凌驾
公共MyViewHolder onCreateViewHolder（视图组父级，int-viewType）{
View itemView=LayoutInflater.from（parent.getContext（））.flate（R.layout.layout\u pdf\u适配器，parent，false）；
返回新的MyViewHolder（itemView）；
}
@凌驾
BindViewHolder上的公共无效（最终MyViewHolder holder1，int索引）{
holder=holder1；
最终int位置=索引；
pdfList=pdfModelClasses.get（位置）；
最终下载的notesdatabase数据库notes=新下载的notesdatabase（上下文）；
holder.txtBookName.setText（pdfList.getSubjectName（）.toUpperCase（））；
holder.txtBookTitle.setText（StringUtils.getTrimString（pdfList.getTypeName（））；
holder.txtbookDateOfIssue.setText（pdfList.getType（））；
holder.txtBookCategory.setText（StringUtils.getTrimString（pdfList.getDescription（））；
if（databaseNotes.isPurchasedNoteSaved（pdfList.getId（），final_nav_opt_name））{
holder.txtDownload.setVisibility（View.VISIBLE）；
holder.layou\u download\u note\u option.setVisibility（View.GONE）；
}否则{
holder.txtDownload.setVisibility（View.GONE）；
holder.layout\u download\u note\u option.setVisibility（View.VISIBLE）；
}
holder.layout\u open\u pdf.setOnClickListener（newview.OnClickListener（））{
@凌驾
公共void onClick（视图v）{
pdfList=pdfModelClasses.get（位置）；
//holder=holder1；
Log.e（“PDFListAdapter”、“布局\打开\ pdf位置=“+位置”）；
Log.e（“PDFListAdapter”，“layout_open_pdf=“+pdfList.getId（））；
if（databaseNotes.isPurchasedNoteSaved（pdfList.getId（），final_nav_opt_name））{
DownloadeNotesModel DownloadeNotesModel=databaseNotes.getnotesbyd（pdfList.getId（），final_nav_opt_name）；
意向意向=新意向（上下文，PDFResults.class）；
intent.putExtra（“pdfList”，downloadeNotesModel.getFileLocation（））；
意向。额外（“来自”、“数据库”）；
putExtra（“getSubjectName”，downloadeNotesModel.getSubjectName（））；
背景。开始触觉（意图）；
}否则{
final AlertDialog.Builder AlertDialog=新建AlertDialog.Builder（上下文）；
alertDialog.setTitle（“警报”）；
alertDialog.setCancelable（真）；
alertDialog.setMessage（“未下载笔记。是否要下载它？”）；
alertDialog.setPositiveButton（“是”，新的DialogInterface.OnClickListener（）{
@RequiresApi（api=Build.VERSION\u code.JELLY\u BEAN\u MR2）
public void onClick（DialogInterface dialog，int which）{
downloader=新的downloader（）；
新建CheckSpace（）.execute（pdfList.getFileName（））；
}
});
/*alertDialog.setNegativeButton（“否”，新的DialogInterface.OnClickListener（）{
@RequiresApi（api=Build.VERSION\u code.JELLY\u BEAN\u MR2）
public void onClick（DialogInterface dialog，int which）{
意向意向=新意向（上下文，PDFResults.class）；
intent.putExtra（“pdfList”，pdfList.getFileName（））；
intent.putExtra（“from”，“url”）；
intent.putExtra（“getSubjectName”，pdfList.getSubjectName（））；
背景。开始触觉（意图）；
}
});*/
alertDialog.show（）；
}
}
});
holder.imgDownloadNote.setOnClickListener（新视图.OnClickListener（）{
@RequiresApi（api=Build.VERSION\u code.JELLY\u BEAN\u MR2）
@凌驾
公共void onClick（视图v）{
Log.e（“PDFListAdapter”、“imgDownloadNote position=“+position”）；
Log.e（“PDFListAdapter”、“imgDownloadNote=“+pdfList.getId（））；
pdfList=pdfModelClasses.get（位置）；
holder=holder1；
如果（！databaseNotes.isPurchasedNoteSaved（pdfList.getId（），final_nav_opt_name））{
if（UtilsMethods.isNetworkAvailable（上下文））{
int result=ContextCompat.checkSelfPermission（上下文，Manifest.permission.READ\u外部存储）；
如果（结果==已授予PackageManager.PERMISSION）{
downloader=新的downloader（）；
新建CheckSpace（）.execute（pdfList.getFileName（））；
}否则{
到
public PDFListAdapter(Context context, ArrayList<NotesResponseInfo> pdfModelClasses, String final_nav_opt_name) {
    this.context = context;
    this.pdfModelClasses = pdfModelClasses;
    this.final_nav_opt_name = final_nav_opt_name;
    databaseNotes = new DatabaseNotes(context);

}
public class MyViewHolder extends RecyclerView.ViewHolder {

    TextView txtBookName, txtBookTitle, txtBookBookDateOFIssue, txtBookCategory, txtDownload;
    LinearLayout layout_open_pdf, layout_download_note_option;
    ImageView imgDownloadNote, imgCancelDownloadNote;
    ProgressBar progress_download_note;
    public MyViewHolder(View view) {
        super(view);

        txtBookName = (TextView) view.findViewById(R.id.txtBookName);
        txtBookTitle = (TextView) view.findViewById(R.id.txtBookTitle);
        txtBookBookDateOFIssue = (TextView) view.findViewById(R.id.txtBookBookDateOFIssue);
        txtBookCategory = (TextView) view.findViewById(R.id.txtBookCategory);
        txtDownload = view.findViewById(R.id.txtDownload);
        layout_open_pdf = (LinearLayout) view.findViewById(R.id.layout_open_pdf);
        layout_download_note_option = (LinearLayout) view.findViewById(R.id.layout_download_note_option);
        imgDownloadNote = (ImageView) view.findViewById(R.id.imgDownloadNote);
        progress_download_note = (ProgressBar) view.findViewById(R.id.progress_download_note);
        imgCancelDownloadNote = (ImageView) view.findViewById(R.id.imgCancelDownloadNote);
    }
}


@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View itemView = LayoutInflater.from(parent.getContext()) .inflate(R.layout.layout_pdf_adapter, parent, false);

    return new MyViewHolder(itemView);
}
@Override
public void onBindViewHolder(final MyViewHolder holder1, int index) {
    holder = holder1;
    final int position = index;
    pdfList = pdfModelClasses.get(position);
    final DownloadedNotesDataBase databaseNotes = new DownloadedNotesDataBase(context);
    holder.txtBookName.setText(pdfList.getSubjectName().toUpperCase());
    holder.txtBookTitle.setText(StringUtils.getTrimString(pdfList.getTypeName()));
    holder.txtBookBookDateOFIssue.setText(pdfList.getType());
    holder.txtBookCategory.setText(StringUtils.getTrimString(pdfList.getDescription()));
    if (databaseNotes.isPurchasedNoteSaved(pdfList.getId(), final_nav_opt_name)) {
      holder.txtDownload.setVisibility(View.VISIBLE);
      holder.layout_download_note_option.setVisibility(View.GONE);
    } else {
        holder.txtDownload.setVisibility(View.GONE);
        holder.layout_download_note_option.setVisibility(View.VISIBLE);
    }
    holder.layout_open_pdf.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            pdfList = pdfModelClasses.get(position);
           // holder = holder1;
            Log.e("PDFListAdapter", "layout_open_pdf position = "+position);
            Log.e("PDFListAdapter", "layout_open_pdf = "+pdfList.getId());
            if (databaseNotes.isPurchasedNoteSaved(pdfList.getId(), final_nav_opt_name)) {
                DownloadeNotesModel downloadeNotesModel = databaseNotes.getNotesByID(pdfList.getId(), final_nav_opt_name);
                Intent intent = new Intent(context, PDFResults.class);
                intent.putExtra("pdfList", downloadeNotesModel.getFileLocation());
                intent.putExtra("from", "database");
                intent.putExtra("getSubjectName", downloadeNotesModel.getSubjectName());
                context.startActivity(intent);
            } else {
                final AlertDialog.Builder alertDialog = new AlertDialog.Builder(context);
                alertDialog.setTitle("Alert");
                alertDialog.setCancelable(true);
                alertDialog.setMessage("Notes not downloaded. Do you want to download it?");
                alertDialog.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR2)
                    public void onClick(DialogInterface dialog, int which) {
                        downloader = new Downloader();
                        new CheckSpace().execute(pdfList.getFileName());
                    }
                });
               /* alertDialog.setNegativeButton("No", new DialogInterface.OnClickListener() {
                    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR2)
                    public void onClick(DialogInterface dialog, int which) {
                        Intent intent = new Intent(context, PDFResults.class);
                        intent.putExtra("pdfList", pdfList.getFileName());
                        intent.putExtra("from", "url");
                        intent.putExtra("getSubjectName", pdfList.getSubjectName());
                        context.startActivity(intent);
                    }
                });*/
                alertDialog.show();
            }
        }
    });

    holder.imgDownloadNote.setOnClickListener(new View.OnClickListener() {
        @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR2)
        @Override
        public void onClick(View v) {
            Log.e("PDFListAdapter", "imgDownloadNote position = "+position);
            Log.e("PDFListAdapter", "imgDownloadNote = "+pdfList.getId());
            pdfList = pdfModelClasses.get(position);
            holder = holder1;
            if (!databaseNotes.isPurchasedNoteSaved(pdfList.getId(), final_nav_opt_name)) {
                if (UtilsMethods.isNetworkAvailable(context)) {
                    int result = ContextCompat.checkSelfPermission(context, Manifest.permission.READ_EXTERNAL_STORAGE);
                    if (result == PackageManager.PERMISSION_GRANTED) {
                        downloader = new Downloader();
                        new CheckSpace().execute(pdfList.getFileName());
                    } else {
                        Toast.makeText(context, "storage permission is not granted", Toast.LENGTH_SHORT).show();
                        PermissionCheck.checkWritePermission(context);
                    }

                } else {
                    holder.imgDownloadNote.setVisibility(View.GONE);
                    holder.imgCancelDownloadNote.setVisibility(View.GONE);
                    holder.progress_download_note.setVisibility(View.GONE);
                    context.startActivity(new Intent(context, NoInternetActivity.class));
                }
            }
            else Log.e("","Not in db");
        }
    });
    holder.imgCancelDownloadNote.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Log.e("PDFListAdapter", "imgCancelDownloadNote position = "+position);
            Log.e("PDFListAdapter", "imgCancelDownloadNote = "+pdfList.getId());
            final AlertDialog alertDialog = new AlertDialog.Builder(context, R.style.AlertDialogStyle).create();
            alertDialog.setTitle("Alert");
            alertDialog.setMessage("Are you sure want to cancel download?");
            alertDialog.setButton("Yes", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    alertDialog.hide();
                    downloader.cancel(true);
                }
            });
            alertDialog.show();
        }
    });
}


@Override
public int getItemCount() {
    return pdfModelClasses.size();
}
@Override
public int getItemViewType(int position)
{
    return  position;
}
private void startSave(final Context context, NotesResponseInfo url) {
    OkHttpClient.Builder httpClient = new OkHttpClient.Builder();
    final base_url b = new base_url();
    Retrofit.Builder builder = new Retrofit.Builder().baseUrl(b.BASE_URL);
    Retrofit retrofit = builder.client(httpClient.build()).build();
    AllApis downloadService = retrofit.create(AllApis.class);
    Call<ResponseBody> call = downloadService.downloadFileByUrl(StringUtils.getCroppedUrl(url.getFileName()));
    call.enqueue(new Callback<ResponseBody>() {
        @Override
        public void onResponse(Call<ResponseBody> call, final Response<ResponseBody> response) {
            if (response.isSuccessful()) {
                mNotifyManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
                mBuilder = new NotificationCompat.Builder(context);
                downloader.execute(response.body());
            } else {

            }
        }

        @Override
        public void onFailure(Call<ResponseBody> call, Throwable t) {
            t.printStackTrace();
        }
    });
}

private class Downloader extends AsyncTask<ResponseBody, Integer, Integer> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        mBuilder.setContentTitle("Download")
                .setContentText("Download in progress")
                .setSmallIcon(R.mipmap.lun);
        mBuilder.setProgress(100, 0, false);
        mNotifyManager.notify(id, mBuilder.build());

    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        mBuilder.setContentTitle("Download")
                .setContentText("Download in progress")
                .setSmallIcon(R.mipmap.lun);
        mBuilder.setProgress(100, values[0], false);
        mNotifyManager.notify(id, mBuilder.build());
        super.onProgressUpdate(values);
    }

    @Override
    protected void onCancelled() {
        super.onCancelled();
        holder.imgDownloadNote.setVisibility(View.VISIBLE);
        holder.imgCancelDownloadNote.setVisibility(View.GONE);
        holder.progress_download_note.setVisibility(View.GONE);
        mNotifyManager.cancelAll();
    }

    @Override
    protected Integer doInBackground(ResponseBody... params) {
        ResponseBody body = params[0];
        try {
            URL url = new URL(pdfList.getFileName());
            HttpURLConnection c = (HttpURLConnection) url.openConnection();
            c.setRequestProperty("Accept-Encoding", "identity");
            c.setRequestMethod("GET");
            c.setDoOutput(true);
            c.connect();
            ContextWrapper wrapper = new ContextWrapper(getApplicationContext());
            int lenghtOfFile = c.getContentLength();
            Log.w("getContentLength",""+lenghtOfFile);
            File file = wrapper.getDir("PDF", MODE_PRIVATE);
            file = new File(file, pdfList.getSubjectName() + "_" + TimeUtils.getCurrentTimeStamp() + ".pdf");
            FileOutputStream f = new FileOutputStream(file);
            InputStream in = c.getInputStream();
            float finalValue = 0;
            byte[] buffer = new byte[100 * 1024];
            int len1 = 0;
            int progress = 0;
            long total = 0;
            if (!(isCancelled())) {
            while ((len1 = in.read(buffer)) !=-1) {
                if (UtilsMethods.isNetworkAvailable(context)) {
                    f.write(buffer, 0, len1);
                    total += len1;
                    setProgress(Integer.parseInt(("" + (int) ((total * 100) / lenghtOfFile))));


                 /*   progress += len1;finalValue = (float) progress/body.contentLength() *100;
                    setProgress((int) finalValue);
                    mBuilder.setProgress((int) finalValue,0,false);*/

                } else {
                    File file1 = new File(file.getPath());
                    file1.delete();
                   cancel(true);

                }
            }
            new DownloadedNotesDataBase(context).addDonloadedNotesToDatabase(file.getPath(), pdfList);
            } else {
                File file1 = new File(file.getPath());
                file1.delete();
                holder.imgDownloadNote.setVisibility(View.VISIBLE);
                holder.imgCancelDownloadNote.setVisibility(View.GONE);
                holder.progress_download_note.setVisibility(View.GONE);
                Toast.makeText(context, "Cancelled", Toast.LENGTH_SHORT).show();
            }

        } catch (FileNotFoundException e1) {
            e1.printStackTrace();
        } catch (ProtocolException e1) {
            e1.printStackTrace();
        } catch (MalformedURLException e1) {
            e1.printStackTrace();
        } catch (IOException e1) {
            e1.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onPostExecute(Integer result) {
        super.onPostExecute(result);
        mBuilder.setContentText("Download complete");
        mBuilder.setSmallIcon(R.mipmap.ic_logo);
        mBuilder.setProgress(100, 100, false);
        mNotifyManager.notify(id, mBuilder.build());
        holder.txtDownload.setVisibility(View.VISIBLE);

        holder.imgDownloadNote.setVisibility(View.GONE);
        holder.imgCancelDownloadNote.setVisibility(View.GONE);
        holder.progress_download_note.setVisibility(View.GONE);
    }

    private void setProgress(int progress) {
        mBuilder.setContentText("Downloading...")
                .setContentTitle(progress + "%")
                .setSmallIcon(R.mipmap.ic_logo)
                .setOngoing(true)
                .setContentInfo(progress + "%")
                .setProgress(100, progress, false);
        mNotifyManager.notify(id, mBuilder.build());
        holder.progress_download_note.setProgress(progress);
    }
}

public class CheckSpace extends AsyncTask<String, Void, String> {
    @Override
    protected String doInBackground(String... params) {
        String file_size = "";
        URL url = null;
        try {
            url = new URL(params[0]);
            URLConnection urlConnection = url.openConnection();
            urlConnection.connect();
            int fileSize = urlConnection.getContentLength();
            file_size = UtilsMethods.generateFileSize(fileSize);
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return file_size;
    }

    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR2)
    @Override
    protected void onPostExecute(String result) {
        if (UtilsMethods.compareSpace(result)) {
            final AlertDialog alertDialog = new AlertDialog.Builder(context, R.style.AlertDialogStyle).create();
            alertDialog.setTitle("Alert");
            alertDialog.setMessage("Download this PDF of size " + result + " ?");
            alertDialog.setButton("Yes", new DialogInterface.OnClickListener() {
                @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR2)
                public void onClick(DialogInterface dialog, int which) {
                    alertDialog.hide();
                    holder.imgDownloadNote.setVisibility(View.GONE);
                    holder.imgCancelDownloadNote.setVisibility(View.VISIBLE);
                    holder.progress_download_note.setVisibility(View.VISIBLE);
                    startSave(context, pdfList);
                }
            });
            alertDialog.show();
        } else {
            final AlertDialog alertDialog = new AlertDialog.Builder(context, R.style.AlertDialogStyle).create();
            alertDialog.setTitle("Alert");
            alertDialog.setMessage("Unable to download file. Storage space is not available");
            alertDialog.setButton("Ok", new DialogInterface.OnClickListener() {
                @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR2)
                public void onClick(DialogInterface dialog, int which) {
                    alertDialog.hide();
                }
            });
            alertDialog.show();
        }
    }



}
}