This is the code that reads the array of installed apps:
(I have tested this and if works fine. I get the app list i want.)

    private void loadApps(){
        manager = getPackageManager();
        ApList.clear();
        Intent i = new Intent(Intent.ACTION_MAIN, null);
        i.addCategory(Intent.CATEGORY_LAUNCHER);
        List<ResolveInfo> availableActivities = manager.queryIntentActivities(i, 0);
        for(ResolveInfo ri:availableActivities){
            String temp = (String) ri.loadLabel(manager);
            if (temp.contains("Phoenix")) {
                if (!temp.contains("Phoenix Launcher")) {
                    ApList.add(new ObjectApp(
                            ri.loadLabel(manager),
                            ri.activityInfo.packageName
                    ));
                }
            }
        }
        ApAdapter.notifyDataSetChanged();
    }

This is my Recycler adapter It only show a single item in the recycler view:

    public class ApAdapter extends RecyclerView.Adapter<ApAdapter.ApViewHolder> {
        private ArrayList<ObjectApp> mApList;
        class ApViewHolder extends RecyclerView.ViewHolder {
            final Button mApBtn;
            ApViewHolder(View ApView) {
                super(ApView);
                mApBtn = ApView.findViewById(R.id.ApBtn);
            }
        }

        ApAdapter(ArrayList<ObjectApp> ApList) {
            mApList = ApList;
        }
        @NonNull
        @Override
        public ApViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_app, parent, false);
            return new ApViewHolder(view);
        }
        @Override
        public void onBindViewHolder(@NonNull ApViewHolder holder, final int pos) {
            ObjectApp currentAp = mApList.get(pos);
            holder.mApBtn.setText(currentAp.getLabel());
            holder.mApBtn.setBackgroundResource(R.drawable.x_green_button);
            holder.mApBtn.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Intent intent = manager.getLaunchIntentForPackage(ApList.get(pos).getName().toString());
                    assert intent != null;
                    intent.putExtra("grade", grade);
                    intent.putExtra("department", department);
                    startActivity(intent);
                }
            });
        }
        @Override
        public int getItemCount() {
            return mApList.size();
        }
    }