在recyclerView中突出显示过滤的文本 [英] Highlight filtered text in recyclerView

问题描述

这是我的适配器类:

public class adapter_cgpa extends RecyclerView.Adapter<adapter_cgpa.Viewholder> implements Filterable {

ArrayList<POJO> cgpaArrayList;
ArrayList<POJO> cgpaArrayListcopy;
String filterPattern = "";


public adapter_cgpa(ArrayList<POJO> cgpaArrayList) {
    this.cgpaArrayList = cgpaArrayList;
    cgpaArrayListcopy = new ArrayList<>(cgpaArrayList);
}

@NonNull
@Override
public adapter_cgpa.Viewholder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

    View listitem = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_cgpa, parent, false);
    return new Viewholder(listitem);
}

@Override
public void onBindViewHolder(@NonNull adapter_cgpa.Viewholder holder, int position) {
    POJO cgpa = cgpaArrayList.get(position);

    if (!filterPattern.equals("")) {
        String tmpCname = cgpa.getCname();
        int startPos = tmpCname.toLowerCase(Locale.US).indexOf(filterPattern.toLowerCase(Locale.US));
        int endPos = startPos + filterPattern.length();
        if (startPos != -1) {
            Spannable spannable = new SpannableString(tmpCname);
            ColorStateList blueColor = new ColorStateList(new int[][]{new int[]{}}, new int[]{Color.BLUE});
            TextAppearanceSpan highlightSpan = new TextAppearanceSpan(null, Typeface.BOLD, -1, blueColor, null);
            spannable.setSpan(highlightSpan, startPos, endPos, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
            holder.cname.setText(spannable);
        } else {
            holder.cname.setText(cgpa.getCname());
        }
    } else {
        holder.cname.setText(cgpa.getCname());
    }

    holder.no_of_sems.setText(cgpa.getNo_of_sems());
    holder.cgpa.setText(cgpa.getCgpa());
    holder.percentage.setText(cgpa.getPercentage());
    holder.schemec.setText(cgpa.getSchemec());

}

@Override
public int getItemCount() {
    return cgpaArrayList.size();
}


@Override
public Filter getFilter() {
    return new Filter() {

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            List<POJO> filteredList = new ArrayList<>();

            if (TextUtils.isEmpty(constraint)) {
                filterPattern="";
                filteredList.addAll(cgpaArrayListcopy);
            } else {
                filterPattern = constraint.toString().toLowerCase().trim();
                for (POJO item : cgpaArrayListcopy) {
                    if (item.getCname().toLowerCase().contains(filterPattern)) {
                        filteredList.add(item);
            //        } else {
            //            filteredList.remove(item);
                    }
                }
            }

            FilterResults results = new FilterResults();
            results.values = filteredList;
            return results;
        }

        @Override
        public void publishResults(CharSequence constraint, FilterResults results) {

            cgpaArrayList.clear();
            cgpaArrayList.addAll((List) results.values);
            notifyDataSetChanged();
        }

    };

}


public class Viewholder extends RecyclerView.ViewHolder {
    TextView cname, no_of_sems, cgpa, percentage, schemec;
    ImageButton btndelete2;

    public Viewholder(@NonNull View itemView) {
        super(itemView);
        cname = itemView.findViewById(R.id.name);
        no_of_sems = itemView.findViewById(R.id.no_of_sem);
        cgpa = itemView.findViewById(R.id.textView49);
        percentage = itemView.findViewById(R.id.textView55);
        schemec = itemView.findViewById(R.id.scheme2);
        btndelete2 = itemView.findViewById(R.id.btndelete2);

        btndelete2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                final AlertDialog.Builder alert = new AlertDialog.Builder(v.getContext());
                alert.setMessage("Are you sure you want to delete this?");

                alert.setNegativeButton("Yes", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {

                    }
                });
                alert.setPositiveButton("No", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int whichButton) {

                    }
                });
                final AlertDialog dialogs = alert.create();
                dialogs.show();
                dialogs.getButton(androidx.appcompat.app.AlertDialog.BUTTON_NEGATIVE).setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {

                        delete(getAdapterPosition());
                        dialogs.dismiss();

                    }
                });
                dialogs.getButton(androidx.appcompat.app.AlertDialog.BUTTON_POSITIVE).setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {

                        dialogs.dismiss();
                    }
                });
            }
        });

    }


    private void delete(int adapterPosition) {

        cgpaArrayList.remove(adapterPosition);
        notifyDataSetChanged();
        final String snc = cname.getText().toString();
        final String semrc = no_of_sems.getText().toString();
        final String schc = schemec.getText().toString();

        dbmanager db = new dbmanager(itemView.getContext());
        db.delete2(snc, semrc, schc);
    }
}

这是我的cgpa_frag片段:

And this is my cgpa_frag fragment:

public class cgpa_frag extends Fragment {

    RecyclerView recyclerview;
    adapter_cgpa ac;
    TextView tv_noContent2;

    ArrayList<POJO> cgpaArrayList = new ArrayList<>();

    public cgpa_frag() {
        // Required empty public constructor
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        setHasOptionsMenu(true);

        View view = inflater.inflate(R.layout.fragment_cgpa_frag, container, false);
        recyclerview = (RecyclerView) view.findViewById(R.id.rc2);
        tv_noContent2 = (TextView)view.findViewById(R.id.tv_noContent2);
        cgpaArrayList = new ArrayList<>();
        Fetchdata2();
        ac = new adapter_cgpa(cgpaArrayList);
        recyclerview.setLayoutManager(new LinearLayoutManager(getContext(), RecyclerView.VERTICAL, false));
        if(cgpaArrayList.isEmpty()){
            recyclerview.setVisibility(View.GONE);
            tv_noContent2.setVisibility(View.VISIBLE);
            tv_noContent2.setText("Look's like you have not saved any CGPA calculation.");

        }else{
            tv_noContent2.setVisibility(View.GONE);
            recyclerview.setVisibility(View.VISIBLE);
            recyclerview.setAdapter(ac);
        }

        return view;
    }

    private void Fetchdata2() {
        dbmanager db = new dbmanager(getContext());

        Cursor cursor = db.fetch_data2();

        if (cursor != null) {

            while (cursor.moveToNext()) {

                POJO pj = new POJO();
                pj.setCname(cursor.getString(0));
                pj.setNo_of_sems(cursor.getString(1));
                pj.setCgpa(cursor.getString(2));
                pj.setPercentage(cursor.getString(3));
                pj.setSchemec(cursor.getString(4));
                cgpaArrayList.add(pj);
            }
            // ac = new adapter_cgpa(cgpaArrayList);
        }
    }

    @Override
    public void onCreateOptionsMenu(@NonNull Menu menu, @NonNull MenuInflater inflater) {

        inflater.inflate(R.menu.search_menu, menu);

        MenuItem searchItem = menu.findItem(R.id.action_search);
        SearchView searchView = (SearchView) searchItem.getActionView();

        searchView.onActionViewExpanded();
        searchView.setIconifiedByDefault(false);
        searchView.setQueryHint("Search by name ... ");

        if(!searchView.isFocused()) {
            searchView.clearFocus();
        }

        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
                ac.getFilter().filter(newText, new Filter.FilterListener() {
                    @Override
                    public void onFilterComplete(int i) {
                        if(i == 0){
                            recyclerview.setVisibility(View.GONE);
                            tv_noContent2.setVisibility(View.VISIBLE);
                            tv_noContent2.setText("No matching results found");
                        }else{
                            tv_noContent2.setVisibility(View.GONE);
                            recyclerview.setVisibility(View.VISIBLE);
                        }
                    }
                });
                return false;
            }
        });
    }

如何从bindviewHolder中的getFilter方法访问filterPattern?我想知道如何从bindviewHolder中的getFilter方法访问filterPattern，以便能够在RecyclerView中突出显示匹配的文本模式.有人可以帮我吗?预先感谢.

How can I access filterPattern from getFilter method in bindviewHolder ? I wanted to know how can I access filterPattern from getFilter method in bindviewHolder so that I am able to highlight the matching text patterns in RecyclerView. Can anyone help me with it ? Thanks in advance.

推荐答案

在ArrayList<POJO> cgpaArrayListcopy;之后添加String filterPattern = "";，然后可以在适配器中的任何位置访问 filterPattern .

Add String filterPattern = ""; after ArrayList<POJO> cgpaArrayListcopy;, then filterPattern can be accessed everywhere in the adapter.

要突出显示过滤的文本，请尝试以下代码:

To highlight filtered text, try the following codes:

@Override
public void onBindViewHolder(@NonNull adapter_cgpa.Viewholder holder, int position) {
    POJO cgpa = cgpaArrayList.get(position);

    if (!filterPattern.equals("")) {
        String tmpCname = cgpa.getCname();
        int startPos = tmpCname.toLowerCase(Locale.US).indexOf(filterPattern.toLowerCase(Locale.US));
        int endPos = startPos + filterPattern.length();
        if (startPos != -1) {
            Spannable spannable = new SpannableString(tmpCname);
            ColorStateList blueColor = new ColorStateList(new int[][]{new int[]{}}, new int[]{Color.BLUE});
            TextAppearanceSpan highlightSpan = new TextAppearanceSpan(null, Typeface.BOLD, -1, blueColor, null);
            spannable.setSpan(highlightSpan, startPos, endPos, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
            holder.cname.setText(spannable);
        } else {
            holder.cname.setText(cgpa.getCname());
        }
    } else {
        holder.cname.setText(cgpa.getCname());
    }

    holder.no_of_sems.setText(cgpa.getNo_of_sems());
    holder.cgpa.setText(cgpa.getCgpa());
    holder.percentage.setText(cgpa.getPercentage());
    holder.schemec.setText(cgpa.getSchemec());
}


        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            List<POJO> filteredList = new ArrayList<>();

            if (TextUtils.isEmpty(constraint)) {
                filterPattern = "";
                filteredList.addAll(cgpaArrayListcopy);
            } else {
                filterPattern = constraint.toString().toLowerCase().trim();
                for (POJO item : cgpaArrayListcopy) {
                    if (item.getCname().toLowerCase().contains(filterPattern)) {
                        filteredList.add(item);
                    //} else {
                    //    filteredList.remove(item);
                    }
                }
            }

            FilterResults results = new FilterResults();
            results.values = filteredList;
            results.count = filteredList.size();

            return results;
        }

希望有帮助！

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