问题
This is my PDFListAdapter class method. I have downloaded file locally and save on Sqlite database. But if I scroll my RecyclerView, then I am having different item id. If not scroll RecyclerView then item id is perfect.
The problem is when I scroll down the RecyclerView the item id changes. That is, I can fit one item on the screen at once. When I scroll to the second item, it saves different file and opens different.
public class PDFListAdapter extends RecyclerView.Adapter<PDFListAdapter.MyViewHolder> {
private ArrayList<NotesResponseInfo> pdfModelClasses;
Context context;
static NotesResponseInfo pdfList;
String final_nav_opt_name;
ProgressDialog progressDialog;
String TAG = "PDFListAdapter";
private NotificationManager mNotifyManager;
private NotificationCompat.Builder mBuilder;
int id = 1;
DatabaseNotes databaseNotes;
MyViewHolder holder;
Downloader downloader;
int deepak =0 ;
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, final int index) {
final int position = index;
pdfList = pdfModelClasses.get(position);
final DownloadedNotesDataBase databaseNotes = new DownloadedNotesDataBase(context);
holder1.txtBookName.setText(pdfList.getSubjectName().toUpperCase());
holder1.txtBookTitle.setText(StringUtils.getTrimString(pdfList.getTypeName()));
holder1.txtBookBookDateOFIssue.setText(pdfList.getType());
holder1.txtBookCategory.setText(StringUtils.getTrimString(pdfList.getDescription()));
if (databaseNotes.isPurchasedNoteSaved(pdfList.getId(), final_nav_opt_name)) {
holder1.txtDownload.setVisibility(View.VISIBLE);
holder1.layout_download_note_option.setVisibility(View.GONE);
} else {
holder1.txtDownload.setVisibility(View.GONE);
holder1.layout_download_note_option.setVisibility(View.VISIBLE);
}
holder1.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.show();
}
}
});
holder1.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);
deepak =index ;
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");
}
});
holder1.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.ic_logo);
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) {
NotesResponseInfo item = new NotesResponseInfo();
item = pdfModelClasses.get(deepak);
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)) >0) {
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();
}
}
@Override
protected void onPreExecute() {
}
@Override
protected void onProgressUpdate(Void... values) {
}
}
}
回答1:
I have modified your onBindViewHolder function. The changes are following.
- Declared the pdfList variable as final and used it everywhere. It is not necessary to get the
pdfListfrom thepdfModelClasses, each time you use it. - The
holdervariable is removed, as it is not actually necessary. Theholder1is used everywhere. - There are some changes with the visibility of the buttons. Check
holder1.imgDownloadNote.setOnClickListener.
I have found no other problem in your onBindViewHolder. Please let me know if the modified code works.
@Override
public void onBindViewHolder(final MyViewHolder holder1, final int index) {
final int position = index;
// Declare the variable here and make it final.
final PDFList pdfList = pdfModelClasses.get(position);
final DownloadedNotesDataBase databaseNotes = new DownloadedNotesDataBase(context);
holder1.txtBookName.setText(pdfList.getSubjectName().toUpperCase());
holder1.txtBookTitle.setText(StringUtils.getTrimString(pdfList.getTypeName()));
holder1.txtBookBookDateOFIssue.setText(pdfList.getType());
holder1.txtBookCategory.setText(StringUtils.getTrimString(pdfList.getDescription()));
if (databaseNotes.isPurchasedNoteSaved(pdfList.getId(), final_nav_opt_name)) {
holder1.txtDownload.setVisibility(View.VISIBLE);
holder1.layout_download_note_option.setVisibility(View.GONE);
} else {
holder1.txtDownload.setVisibility(View.GONE);
holder1.layout_download_note_option.setVisibility(View.VISIBLE);
}
holder1.layout_open_pdf.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// I have the desired pdfList already, no need to get that again.
// pdfList = pdfModelClasses.get(position);
// Assigning to holder is not necessary.
// 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.show();
}
}
});
holder1.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);
deepak =index ;
// We don't need the reassignment.
// 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());
// Make them visible when the internet connection is there.
holder1.imgDownloadNote.setVisibility(View.VISIBLE);
holder1.imgCancelDownloadNote.setVisibility(View.VISIBLE);
holder1.progress_download_note.setVisibility(View.VISIBLE);
} else {
Toast.makeText(context, "storage permission is not granted", Toast.LENGTH_SHORT).show();
PermissionCheck.checkWritePermission(context);
holder1.imgDownloadNote.setVisibility(View.GONE);
holder1.imgCancelDownloadNote.setVisibility(View.GONE);
holder1.progress_download_note.setVisibility(View.GONE);
}
} else {
holder1.imgDownloadNote.setVisibility(View.GONE);
holder1.imgCancelDownloadNote.setVisibility(View.GONE);
holder1.progress_download_note.setVisibility(View.GONE);
context.startActivity(new Intent(context, NoInternetActivity.class));
}
} else {
// Put proper visibility everywhere.
holder1.imgDownloadNote.setVisibility(View.GONE);
holder1.imgCancelDownloadNote.setVisibility(View.GONE);
holder1.progress_download_note.setVisibility(View.GONE);
Log.e("","Not in db");
}
}
});
holder1.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;
}
来源：https://stackoverflow.com/questions/49584607/if-recyclerview-scrolls-then-item-id-changes-how-to-resolve-this