CODEWITHSUNDEEP
javaandroidandroid-recyclerviewsharedpreferences
SCS
SCS

Reputation: 23

Recycler Adapter and Shared preferences

i have a simple use case here, a list of words saved using shardpreferences, displayed using recycler view. i need to add words and delete words

to add words:

public void get_word(String new_word) {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(String.valueOf(sharedPreferences.getAll().size()), new_word);
        System.out.println(sharedPreferences.getAll());
        editor.commit();
        vocabL.add(new_word);
        adapter.notifyItemInserted(vocabL.size() - 1);
        VVlist.scrollToPosition(vocabL.size() -1);
    }

the idea here is quite simple and buggy, the keys im using for shared preferences are numbers, so here i used the size function which would return the next number i can use but here is the issue:

 public void onBindViewHolder(@NonNull RecyclerAdapter.ViewHolder holder, int position) {
        holder.textView.setText(list.get(position));
        holder.textView.setOnClickListener(v -> Toast.makeText(context, "Clicked on " + holder.getAbsoluteAdapterPosition(), Toast.LENGTH_SHORT).show());
        holder.textView.setOnLongClickListener(view -> {
            AlertDialog.Builder builder = new AlertDialog.Builder(context)
                    .setTitle("Delete word")
                    .setMessage("are you sure you want to delete?")
                    .setPositiveButton("yes", (dialogInterface, i) -> {
                        list.remove(holder.getAbsoluteAdapterPosition());                        editor.remove(String.valueOf(holder.getAbsoluteAdapterPosition()));
                        notifyItemRemoved(holder.getAbsoluteAdapterPosition());
                        editor.commit();
                    })
                    .setNegativeButton("no", (dialogInterface, i) -> {

                    });
            builder.show();
            return true;
        });
    }

here when i delete a word, i loose the key as well so i guess the problem is clear, the next time i try to add a word, i override an existing value also there are other problems with this inefficient code, when deleting, the position can differ to the key, hence deleting something that wasnt meant to be deleted

there is a list 'list' in the above code, which is nothing but a list containing all the words, i used it for testing possible solutions

im self taught, im not aware of the right programming practises to use here. the only possible solution i can think of is using the map interface, but i feel like there are better ways to go around this thanks

Upvotes: 0

Views: 320

Answers (2)

SCS
SCS

Reputation: 23

public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        holder.textView.setText(pist.get(position).toString());
        holder.textView.setTag(pist.get(position).toString());
        holder.textView.setOnClickListener(v -> Toast.makeText(context, "Clicked on " + holder.getAbsoluteAdapterPosition(), Toast.LENGTH_SHORT).show());
        holder.textView.setOnLongClickListener(view -> {
            AlertDialog.Builder builder = new AlertDialog.Builder(context)
                    .setTitle("Delete word")
                    .setMessage("are you sure you want to delete?")
                    .setPositiveButton("yes", (dialogInterface, i) -> {
                        pist.remove(holder.getAbsoluteAdapterPosition());
                        editor.remove(String.valueOf(view.getTag()));
                        notifyItemRemoved(holder.getAbsoluteAdapterPosition());
                        editor.commit();
                    })
                    .setNegativeButton("no", (dialogInterface, i) -> {

                    });
            builder.show();
            return true;
        });
    }

the solution i found is to use tags for identification, i made a list(pist) of all the values in the shared preferences and im using the words as the keys, since its more convenient, if needed we could always make another list of keys and set the tag accordingly im not sure if this is the professional way to go abt it, but it works fine and seems decent enough nevertheless Im still open to answers

Upvotes: 0

return 0
return 0

Reputation: 142

This is how I'd do it.

1.Have a model for the words

data class Word(var id:Long,var word:String)

2.Populate a list of the words for the recycler view. For ID, use System.nanotime() & 0xfffff. This guarantees a unique ID every time it is called( at least I tested it against a million iterations).

val wordlist= mutableListOf<Word>()

for (s in 0 until 10){
val word=Word((System. nanotime & 0xfffff).toLong(),"Some random string")

worldList.add(word)
//save the word to preference with the key word.id
  1. In your adapter in onBindViewHolder
val word= worldList[position]

yourTextView.text=word

yourDeleteView.setOnClickListener{
val wordID=word.id
deleteWord(wordID)
}

Upvotes: 1

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