2 version add patient view

+package com.sw.laryngoscope.FHIR.adapter;
+
+import android.view.ViewGroup;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.sw.laryngoscope.FHIR.model.PatientModel;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+
+public abstract class BaseAdapter<H extends BaseViewHolder> extends RecyclerView.Adapter<BaseViewHolder> {
+    private HashMap<String, PatientModel> patientsHashMap;
+    private ArrayList<PatientModel> uniquePatients = new ArrayList<>();
+
+    /**
+     * Constructor.
+     */
+    BaseAdapter(HashMap<String, PatientModel> patientsHashMap) {
+        this.patientsHashMap = patientsHashMap;
+    }
+
+    /**
+     * Getter for PatientHashMap
+     * @return the patientHashMap
+     */
+    HashMap<String, PatientModel> getPatientsHashMap() {
+        return patientsHashMap;
+    }
+
+    /**
+     * Setter for PatientHashMap
+     * @param patientsHashMap new PatientHashMap
+     */
+    void setPatientsHashMap(HashMap<String, PatientModel> patientsHashMap) {
+        this.patientsHashMap = patientsHashMap;
+    }
+
+
+    /**
+     * Getter for uniquePatients
+     * @return uniquePatients
+     */
+    ArrayList<PatientModel> getUniquePatients() {
+        return uniquePatients;
+    }
+
+    /**
+     * Setter for uniquePatients
+     * @param uniquePatients new uniquePatients list
+     */
+    void setUniquePatients(ArrayList<PatientModel> uniquePatients) {
+        this.uniquePatients = uniquePatients;
+    }
+
+    /**
+     * onCreateViewHolder overrides it superclass's ( RecyclerView ) method
+     * subclass of this class must implement this method.
+     */
+    @NonNull
+    @Override
+    public abstract BaseViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType);
+
+    /**
+     * onBindViewHolder overrides it superclass's ( RecyclerView ) method
+     * subclass of this class must implement this method.
+     */
+    @Override
+    public abstract void onBindViewHolder(@NonNull BaseViewHolder holder, int position);
+
+    /**
+     * onGetItemCount overrides it superclass's ( RecyclerView ) method
+     * subclass of this class must implement this method.
+     */
+    @Override
+    public abstract int getItemCount();
+}

+package com.sw.laryngoscope.FHIR.adapter;
+
+import android.view.View;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+
+public abstract class BaseViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
+    /**
+     * Constructor.
+     * @param itemView
+     */
+    BaseViewHolder(@NonNull View itemView) {
+        super(itemView);
+    }
+
+    /**
+     * On click method from View.OnClickListener interface
+     * Subclass that inherits from this class must implement this method.
+     */
+    @Override
+    public abstract void onClick(View v);
+
+}

+package com.sw.laryngoscope.FHIR.adapter;
+
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.CheckBox;
+import android.widget.TextView;
+
+import androidx.annotation.NonNull;
+import androidx.constraintlayout.widget.ConstraintLayout;
+
+import com.google.android.material.chip.Chip;
+import com.sw.laryngoscope.R;
+import com.sw.laryngoscope.FHIR.model.PatientModel;
+import com.sw.laryngoscope.FHIR.model.observation.ObservationType;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Objects;
+
+public class SelectPatientsAdapter extends  BaseAdapter<SelectPatientsAdapter.SelectPatientViewHolder>{
+    // select patients adapter on pcl
+    private OnPatientClickListener onPatientClickListener;
+    private ArrayList<PatientModel> selectedPatients;
+    // A list to remember a patient's state
+    // ( true when patient is selected , otherwise false)
+    private ArrayList<Boolean> patientState = new ArrayList<>();
+    /**
+     * The SelectPatient Adapter constructor, this initialises the adapter that
+     * will be used to update the SelectPatient fragment UI.
+     *
+     * @param patientsHashMap list of patients that is under HealthPractitioner
+     * @param onPatientClickListener the listener that is listening to each patient's card clicks
+     * @param selectedPatients a list of selected patients
+     */
+    public SelectPatientsAdapter(HashMap<String, PatientModel> patientsHashMap, OnPatientClickListener onPatientClickListener, ArrayList<PatientModel> selectedPatients) {
+        super(patientsHashMap);
+        this.selectedPatients = selectedPatients;
+        this.onPatientClickListener = onPatientClickListener;
+
+        ArrayList<PatientModel> uniquePatients = new ArrayList<>();
+
+        // loop through the patient hash map to get a list of unique patients
+        patientsHashMap.forEach((patientID, patientModel) -> {
+            if (patientModel != null) {
+
+                PatientModel selectedPatient = isSelectedPatient(patientModel);
+                if (selectedPatient != null) {
+                    uniquePatients.add(selectedPatient);
+                    patientState.add(true);
+                }
+                else {
+                    uniquePatients.add(patientModel);
+                    patientState.add(false);
+                }
+            }
+        });
+        setUniquePatients(uniquePatients);
+    }
+
+    /**
+     * This method checks if patient is already in the selected patient list.
+     * @param patient - the patient model object
+     * @return true - if patient is already in the selected patient list
+     *         false - if patient is not in the selected patient list
+     */
+    private PatientModel isSelectedPatient(PatientModel patient) {
+        for (PatientModel p: selectedPatients) {
+            if(p.getPatientID().equals(patient.getPatientID())) {
+                return p;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * This method overrides its superclass's onCreateViewHolder method
+     * It is responsible for creating new card view holders that will be used to hold
+     * and display patient'name
+
+     * @return a ViewHolder Object
+     */
+    @NonNull
+    @Override
+    public BaseViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.select_patients_cardview, parent, false);
+        return new SelectPatientsAdapter.SelectPatientViewHolder(v, onPatientClickListener);
+    }
+
+    /**
+     * This method overrides its superclass's onBindViewHolder method
+     * This method is used to update the contents of the SelectPatientViewHolder to reflect the patient
+     * at the given position.
+     *
+     * This method also checks if patient is a selected patient and do the following:
+     * 1. if true -> highlight the patient's card view in green
+     * 2. else -> don't highlight the patient's card view
+     *
+     * @param baseHolder the reference to the holder that will be used to display the patient's name
+     * @param position the position of the adapter
+     */
+    @Override
+    public void onBindViewHolder(@NonNull BaseViewHolder baseHolder, int position) {
+        SelectPatientViewHolder holder = (SelectPatientViewHolder) baseHolder;
+        holder.checkBox.setChecked(patientState.get(position));
+        holder.background.setBackgroundResource(R.drawable.cardv_nonselected_bg);
+        holder.patientName.setText(getUniquePatients().get(position).getName());
+        PatientModel patient = getUniquePatients().get(position);
+        if (isSelectedPatient(patient) != null){
+            holder.checkBox.setChecked(true);
+            holder.background.setBackgroundResource(R.drawable.cardv_selected_bg);
+            patientState.set(position,true);
+            onPatientClickListener.onPatientClick(holder.checkBox.isChecked(), getUniquePatients().get(position));
+            // set chip to be checked if selected for monitoring observation(s) previously
+            for (ObservationType type: ObservationType.values()) {
+                switch (type) {
+                    case CHOLESTEROL:
+                        if (Objects.requireNonNull(isSelectedPatient(patient)).isObservationMonitored(type)) {
+                            holder.cholesterolChip.setChecked(true);
+                        }
+                        else {
+                            holder.cholesterolChip.setChecked(false);
+                        }
+                    case BLOOD_PRESSURE:
+                        if (Objects.requireNonNull(isSelectedPatient(patient)).isObservationMonitored(type)) {
+                            holder.bloodPressureChip.setChecked(true);
+                        }
+                        else {
+                            holder.bloodPressureChip.setChecked(false);
+                        }
+                }
+            }
+        }
+    }
+
+    /**
+     * This method overrides its superclass's method,
+     * It gets the total number of patients that is under HeathPractitioner
+     * @return total number of patients
+     */
+    @Override
+    public int getItemCount() {
+        return getUniquePatients().size();
+    }
+
+    /**
+     * The SelectPatientViewHolder class are objects that holds the reference to the individual
+     * card views that is reused to display different patient's data in the recycler view.
+     *
+     * This class implements View.OnClickListener interface.
+     */
+    public class SelectPatientViewHolder extends BaseViewHolder {
+        private TextView patientName;
+        private CheckBox checkBox; //hidden checkbox
+        private SelectPatientsAdapter.OnPatientClickListener onPatientClickListener;
+        private ConstraintLayout background;
+        private Chip cholesterolChip;
+        private Chip bloodPressureChip;
+
+        /**
+         * The SelectPatientViewHolder constructor
+         * initialise SelectPatientViewHolder object that will be used to hold patient's data
+         * @param onPatientClickListener the listener that is listening to patient's card clicks
+         */
+        SelectPatientViewHolder(@NonNull View itemView, OnPatientClickListener onPatientClickListener) {
+            super(itemView);
+            patientName = itemView.findViewById(R.id.all_patient_txt_name);
+            checkBox = itemView.findViewById(R.id.checkBox);
+            background = itemView.findViewById(R.id.card_backgroud);
+            cholesterolChip = itemView.findViewById(R.id.cholesterol_chip);
+            bloodPressureChip = itemView.findViewById(R.id.blood_pressure_chip);
+            this.onPatientClickListener = onPatientClickListener;
+            itemView.setOnClickListener(this);
+            cholesterolChip.setOnClickListener(this);
+            bloodPressureChip.setOnClickListener(this);
+        }
+
+        private void observationStatus(Chip chip, int position, ObservationType observationType) {
+            if (chip.isChecked()) {
+                getUniquePatients().get(position).monitorObservation(observationType, true);
+                background.setBackgroundResource(R.drawable.cardv_selected_bg);
+                checkBox.setChecked(true);
+                patientState.set(position,true);
+            }
+            else {
+                if (!cholesterolChip.isChecked() && !bloodPressureChip.isChecked()) {
+                    patientState.set(position,false);
+                    background.setBackgroundResource(R.drawable.cardv_nonselected_bg);
+                    checkBox.setChecked(false);
+                }
+                getUniquePatients().get(position).monitorObservation(observationType, false);
+            }
+        }
+
+        /**
+         * This method is called when user clicks on a patient's card-view.
+         * It notifies its onClickListener (SelectPatientFragment) to add the patient into the
+         * selected patient list/ remove the patient form the selected patient list
+         */
+        @Override
+        public void onClick(View v) {
+            switch (v.getId()) {
+                case R.id.cholesterol_chip:
+                    observationStatus(cholesterolChip, getAdapterPosition(), ObservationType.CHOLESTEROL);
+                    break;
+                case R.id.blood_pressure_chip:
+                    observationStatus(bloodPressureChip, getAdapterPosition(), ObservationType.BLOOD_PRESSURE);
+                    break;
+            }
+            onPatientClickListener.onPatientClick(checkBox.isChecked(), getUniquePatients().get(getAdapterPosition()));
+        }
+    }
+
+    /**
+     * Class the uses this interface must implement their own onPatientClick method.
+     * onPatientClick is handle the events that should happen when a patient's card-view is clicked.
+     */
+    public interface OnPatientClickListener {
+        void onPatientClick(boolean checked, PatientModel patient);
+    }
+
+}

+package com.sw.laryngoscope.FHIR.fragment;
+
+
+import android.content.Context;
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Toast;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.appcompat.widget.Toolbar;
+import androidx.fragment.app.Fragment;
+import androidx.lifecycle.Observer;
+import androidx.lifecycle.ViewModelProvider;
+import androidx.recyclerview.widget.LinearLayoutManager;
+
+import com.sw.laryngoscope.R;
+import com.sw.laryngoscope.FHIR.adapter.SelectPatientsAdapter;
+import com.sw.laryngoscope.databinding.FgPatientFragmentBinding;
+import com.sw.laryngoscope.FHIR.model.PatientModel;
+import com.sw.laryngoscope.FHIR.viewModel.SharedViewModel;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+
+public class SelectPatientsFragment extends Fragment implements SelectPatientsAdapter.OnPatientClickListener{
+    private String practitionerID;
+    private SelectPatientsFragment thisFrag; // a reference to this fragment
+//    private Toolbar toolbar;
+    private SharedViewModel sharedViewModel;
+//    private RecyclerView recyclerView;
+    private ArrayList<PatientModel> selectedPatients = new ArrayList<>();
+//    private TextView title;
+//    private TextView loadingTextView;
+//    private ImageButton backButton;
+//    private ProgressBar loadingSpinner;
+
+    private FgPatientFragmentBinding binding;
+
+    /**
+     * Constructor
+     * @param practitionerID the Health Practitioner's ID
+     */
+    public SelectPatientsFragment(String practitionerID) {
+        this.practitionerID = practitionerID;
+    }
+
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
+                             @Nullable Bundle savedInstanceState) {
+
+        binding = FgPatientFragmentBinding.inflate(inflater, container, false);
+
+        return binding.getRoot();
+    }
+
+    public void onViewCreatred(@NonNull View view,@Nullable Bundle savedInstanceState){
+
+        sharedViewModel = new ViewModelProvider(requireActivity()).get(SharedViewModel.class);
+
+        // find all the graphical components
+//        recyclerView = root.findViewById(R.id.select_patients_recycler_view);
+//        backButton = root.findViewById(R.id.btn_back);
+//        toolbar = root.findViewById(R.id.select_patients_toolbar);
+//        title = toolbar.findViewById(R.id.toolbar_title);
+//        loadingTextView = root.findViewById(R.id.select_patients_txt_loading);
+//        loadingSpinner = root.findViewById(R.id.select_patients_progressBar);
+
+        binding.selectPatientsTxtLoading.setVisibility(View.VISIBLE);
+        binding.selectPatientsProgressBar.setVisibility(View.VISIBLE);
+
+        sharedViewModel.setPractitionerID(practitionerID);
+        setUpToolBar();
+
+        //update UI when there's new patient under Health Practitioner
+        sharedViewModel.getAllPatients().observe(getViewLifecycleOwner(),patientUpdatedObserver);
+
+        thisFrag = this;
+    }
+
+    /**
+     * This observer observes for changes in patient list
+     * ( The list that contains all patients under Health Practitioner )
+     * It displays a loading screen when the app is still fetching data from the server,
+     * It immediately updates the UI to display the patients when the system completes
+     * the data fetching process.
+     */
+    private Observer<HashMap<String,PatientModel>> patientUpdatedObserver = new Observer<HashMap<String,PatientModel >>() {
+        @Override
+        public void onChanged( HashMap < String, PatientModel > patientHashMap) {
+            if (patientHashMap.size() == 0) {
+                binding.selectPatientsTxtLoading.setText(R.string.zero_patients_message);
+            }
+            else{
+                binding.selectPatientsProgressBar.setVisibility(View.GONE);
+                binding.selectPatientsTxtLoading.setVisibility(View.GONE);
+                binding.selectPatientsRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
+                binding.selectPatientsRecyclerView.setAdapter( new SelectPatientsAdapter(patientHashMap,thisFrag, selectedPatients));
+            }
+        }
+    };
+
+    private void setUpToolBar() {
+        binding.selectPatientsToolbar.toolbarTitle.setText(R.string.title_patient_selection);
+        binding.selectPatientsToolbar.getRoot().inflateMenu(R.menu.select_patients_menu);
+        Toolbar.OnMenuItemClickListener menuItemClickListener = item -> {
+            if (selectedPatients.size() > 0) {
+                // save list into view model
+                sharedViewModel.setSelectedPatients(selectedPatients);
+//                MainActivity main = (MainActivity) getActivity();
+//                Objects.requireNonNull(main).findFragment(MainActivity.home_fragment);
+            } else {
+                String message = "Please select AT LEAST 1 patient";
+                Context context = getContext();
+                Toast toast = Toast.makeText(context, message, Toast.LENGTH_LONG);
+                toast.show();
+            }
+            return true;
+        };
+        binding.selectPatientsToolbar.getRoot().setOnMenuItemClickListener(menuItemClickListener);
+
+        binding.selectPatientsToolbar.btnBack.setOnClickListener(v -> {
+//            MainActivity main = (MainActivity) getActivity();
+//            Objects.requireNonNull(main).findFragment(MainActivity.login_fragment);
+        });
+    }
+
+    public void onPatientClick(boolean checked, PatientModel patient) {
+        PatientModel patientWithSameID = null;
+        boolean found = false;
+        for (PatientModel p : selectedPatients){
+            if(p.getPatientID().equals(patient.getPatientID())){
+                found = true;
+                patientWithSameID = p;
+                break;
+            }
+        }
+        if (checked) {
+            if (!found) {
+                selectedPatients.add(patient);
+            }
+        } else if (!checked) {
+            if(found){
+                selectedPatients.remove(patientWithSameID);
+            }else{
+                selectedPatients.remove(patient);
+            }
+        }
+        updateToolbar();
+    }
+
+    /**
+     * This method updates the tool bar to display the total number of patients that is currently
+     * being selected
+     */
+    private void updateToolbar() {
+        String text = selectedPatients.size() + " Patients Selected";
+        // Log.d("Select_Patient_Fragment","current sellected patient : " + selected_patients.toString());
+        binding.selectPatientsToolbar.toolbarTitle.setText(text);
+    }
+
+}

-package com.sw.laryngoscope.model;
+package com.sw.laryngoscope.FHIR.model;
 
 public class PatientAddressModel {
     private String city;

-package com.sw.laryngoscope.model;
+package com.sw.laryngoscope.FHIR.model;
 
 import android.text.format.DateFormat;
 
-import com.sw.laryngoscope.model.observation.BloodPressureObservationModel;
-import com.sw.laryngoscope.model.observation.ObservationModel;
-import com.sw.laryngoscope.model.observation.ObservationType;
+import com.sw.laryngoscope.FHIR.model.observation.BloodPressureObservationModel;
+import com.sw.laryngoscope.FHIR.model.observation.ObservationModel;
+import com.sw.laryngoscope.FHIR.model.observation.ObservationType;
 
 import org.hl7.fhir.r4.model.Enumerations;
 

-package com.sw.laryngoscope.model.observation;
+package com.sw.laryngoscope.FHIR.model.observation;
 
 import org.hl7.fhir.r4.model.Observation;
 

-package com.sw.laryngoscope.model.observation;
+package com.sw.laryngoscope.FHIR.model.observation;
 
 import org.hl7.fhir.r4.model.Observation;
 

-package com.sw.laryngoscope.model.observation;
+package com.sw.laryngoscope.FHIR.model.observation;
 
 import org.hl7.fhir.r4.model.Observation;
 

-package com.sw.laryngoscope.model.observation;
+package com.sw.laryngoscope.FHIR.model.observation;
 
 public enum ObservationType {
     CHOLESTEROL, BLOOD_PRESSURE;

-package com.sw.laryngoscope.service;
+package com.sw.laryngoscope.FHIR.service;
 
 import ca.uhn.fhir.context.FhirContext;
 import ca.uhn.fhir.rest.client.api.IGenericClient;

-package com.sw.laryngoscope.service.repository;
+package com.sw.laryngoscope.FHIR.service.repository;
 
-import com.sw.laryngoscope.model.observation.BloodPressureObservationModel;
-import com.sw.laryngoscope.model.observation.CholesterolObservationModel;
-import com.sw.laryngoscope.model.observation.ObservationModel;
-import com.sw.laryngoscope.model.observation.ObservationType;
-import com.sw.laryngoscope.service.FhirService;
+import com.sw.laryngoscope.FHIR.model.observation.BloodPressureObservationModel;
+import com.sw.laryngoscope.FHIR.model.observation.CholesterolObservationModel;
+import com.sw.laryngoscope.FHIR.model.observation.ObservationModel;
+import com.sw.laryngoscope.FHIR.model.observation.ObservationType;
+import com.sw.laryngoscope.FHIR.service.FhirService;
 
 import org.hl7.fhir.r4.model.Bundle;
 import org.hl7.fhir.r4.model.Observation;

-package com.sw.laryngoscope.service.repository;
+package com.sw.laryngoscope.FHIR.service.repository;
 
-import com.sw.laryngoscope.model.PatientAddressModel;
-import com.sw.laryngoscope.model.PatientModel;
-import com.sw.laryngoscope.service.FhirService;
+import com.sw.laryngoscope.FHIR.model.PatientAddressModel;
+import com.sw.laryngoscope.FHIR.model.PatientModel;
+import com.sw.laryngoscope.FHIR.service.FhirService;
 
 import org.hl7.fhir.r4.model.Bundle;
 import org.hl7.fhir.r4.model.Encounter;

+package com.sw.laryngoscope.FHIR.viewModel;
+
+public interface Poll {
+    void polling();
+}

+package com.sw.laryngoscope.FHIR.viewModel;
+
+import android.util.Log;
+
+import android.os.Handler;
+import android.os.HandlerThread;
+
+
+import androidx.lifecycle.MutableLiveData;
+import androidx.lifecycle.ViewModel;
+import androidx.lifecycle.LiveData;
+
+import com.sw.laryngoscope.FHIR.model.PatientModel;
+import com.sw.laryngoscope.FHIR.model.observation.ObservationModel;
+import com.sw.laryngoscope.FHIR.model.observation.ObservationType;
+import com.sw.laryngoscope.FHIR.service.repository.ObservationRepositoryFactory;
+import com.sw.laryngoscope.FHIR.service.repository.PatientRepository;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Objects;
+
+public class SharedViewModel extends ViewModel implements Poll {
+    // for polling
+    private MutableLiveData<HashMap<String, PatientModel>> patientObservations = new MutableLiveData<>();
+    // to get all the patients under practitioner
+    private MutableLiveData<HashMap<String, PatientModel>> allPatients = new MutableLiveData<>();
+    private String practitionerID = "";
+    private PatientRepository patientRepository;
+    private ObservationRepositoryFactory observationRepositoryFactory;
+    private MutableLiveData<String> selectedFrequency = new MutableLiveData<>() ;
+    private MutableLiveData<ArrayList<PatientModel>> selectedPatients = new MutableLiveData<>();
+
+    private void initShareViewModel() {
+        patientRepository = new PatientRepository(practitionerID);
+        observationRepositoryFactory = new ObservationRepositoryFactory();
+        fetchAllPatients();
+        setSelectedPatients(new ArrayList<>());
+        selectedFrequency.setValue("10");
+    }
+
+    public void setPractitionerID(String practitionerID) {
+        this.practitionerID = practitionerID;
+        initShareViewModel();
+    }
+
+    public LiveData<String> getSelectedFrequency() {
+        return selectedFrequency;
+    }
+
+    public void updateCurrentSelected(String currentSelected) {
+        this.selectedFrequency.setValue(currentSelected);
+    }
+
+    public LiveData<HashMap<String, PatientModel>> getAllPatientObservations() {
+        return patientObservations;
+    }
+
+    public void setSelectedPatients(ArrayList<PatientModel> selectedPatientsArray) {
+        selectedPatients.setValue(selectedPatientsArray);
+    }
+
+    public LiveData<HashMap<String, PatientModel>> getAllPatients() {
+        return allPatients;
+    }
+
+    private ObservationModel getObservation(String id, ObservationType observationType) {
+        return observationRepositoryFactory.getObservationModel(id, observationType);
+    }
+
+    private void fetchAllPatients() {
+        // run asynchronous tasks on background thread to prevent network on main exception
+        HandlerThread backgroundThread = new HandlerThread("Background Thread");
+        backgroundThread.start();
+        Handler timer = new Handler(backgroundThread.getLooper());
+
+        timer.post(() -> {
+            HashMap < String, PatientModel > patientHashMap = new HashMap<>();
+            // loop through all patients
+            for (PatientModel patient : patientRepository.getAllPatients()) {
+                try {
+                    // only show patients with cholesterol and bp values
+                    for (ObservationType type: ObservationType.values()) {
+                        patient.setObservation(type, getObservation(patient.getPatientID(), type));
+                        patientHashMap.put(patient.getPatientID(), patient);
+                    }
+                    patient.addLatestBPReadings(observationRepositoryFactory.getLatestBloodPressureReadings(patient.getPatientID(),5));
+
+                }
+                // patient does not have the observation type
+                catch (Exception e) {
+                    Log.e("Patient ", "No observation type");
+                }
+            }
+
+            // update LiveData and notify observers - used by select patient
+            allPatients.postValue(patientHashMap);
+        });
+
+        polling();
+    }
+
+    public void polling() {
+
+        // run asynchronous tasks on background thread to prevent network on main exception
+        HandlerThread backgroundThread = new HandlerThread("Background Thread");
+        backgroundThread.start();
+        Handler timer = new Handler(backgroundThread.getLooper());
+
+        timer.post(new Runnable() {
+            @Override
+            public void run() {
+                HashMap<String, PatientModel> poHashMap = new HashMap<>();
+
+                // loop through all patients. update observations if observation is selected to be monitored
+                for (PatientModel patientModel: Objects.requireNonNull(selectedPatients.getValue())) {
+                    for (ObservationType type: ObservationType.values()) {
+                        if (patientModel.isObservationMonitored(type)) {
+                            patientModel.setObservation(type, getObservation(patientModel.getPatientID(), type));
+                            poHashMap.put(patientModel.getPatientID(), patientModel);
+                            if (type == ObservationType.BLOOD_PRESSURE) {
+                                patientModel.addLatestBPReadings(observationRepositoryFactory.getLatestBloodPressureReadings(patientModel.getPatientID(),5));
+                            }
+                        }
+                    }
+                }
+
+                // update LiveData and notify observers
+                patientObservations.postValue(poHashMap);
+                timer.postDelayed(this, Integer.parseInt(Objects.requireNonNull(getSelectedFrequency().getValue()))*1000);
+            }});
+    }
+}

+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+    <solid android:color="@color/unselected" />
+    <corners android:radius="50dp" />
+</shape>
\ No newline at end of file

+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+    <solid android:color="@color/color_accent" />
+    <corners android:radius="10dp" />
+</shape>
\ No newline at end of file

+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android"
+    android:shape="rectangle">
+    <solid android:color="@color/color_selected_patient" />
+    <corners android:radius="10dp" />
+</shape>

+<vector android:height="24dp" android:tint="#FFFFFF"
+    android:viewportHeight="24.0" android:viewportWidth="24.0"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FF000000" android:pathData="M20,11H7.83l5.59,-5.59L12,4l-8,8 8,8 1.41,-1.41L7.83,13H20v-2z"/>
+</vector>
\ No newline at end of file

+<?xml version="1.0" encoding="utf-8"?>
+<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    xmlns:card_view="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/card_layout"
+    android:foreground="?selectableItemBackground"
+    card_view:cardBackgroundColor="@color/color_accent"
+    card_view:cardCornerRadius="12dp"
+    card_view:cardElevation="3dp"
+    android:layout_margin="5dp"
+    >
+
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:id="@+id/card_backgroud"
+        android:layout_width="match_parent"
+        android:layout_height="94dp">
+
+
+        <LinearLayout
+            android:id="@+id/linear_layout"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            card_view:layout_constraintBottom_toBottomOf="parent"
+            card_view:layout_constraintEnd_toStartOf="@id/guideline2"
+            card_view:layout_constraintHorizontal_bias="0"
+            card_view:layout_constraintStart_toStartOf="parent"
+            card_view:layout_constraintTop_toTopOf="parent"
+            card_view:layout_constraintVertical_bias="0.5">
+
+            <CheckBox
+                android:id="@+id/checkBox"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:theme="@style/checkBoxStyle"
+                android:visibility="gone" />
+
+        </LinearLayout>
+
+
+        <TextView
+            android:id="@+id/all_patient_txt_name"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:text="@string/patient_name"
+            android:textSize="25sp"
+            card_view:layout_constraintBottom_toBottomOf="@id/linear_layout"
+            card_view:layout_constraintEnd_toStartOf="@id/guideline2"
+            card_view:layout_constraintHorizontal_bias="0.0"
+            card_view:layout_constraintStart_toEndOf="@id/guideline"
+            card_view:layout_constraintTop_toTopOf="parent"
+            card_view:layout_constraintVertical_bias="0.285" />
+
+        <androidx.constraintlayout.widget.Guideline
+            android:id="@+id/guideline"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            card_view:layout_constraintGuide_percent="0.04" />
+
+        <androidx.constraintlayout.widget.Guideline
+            android:id="@+id/guideline2"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            card_view:layout_constraintGuide_percent="0.96" />
+
+        <com.google.android.material.chip.Chip
+            android:id="@+id/cholesterol_chip"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="45dp"
+            android:layout_marginTop="8dp"
+            android:layout_marginEnd="267dp"
+            android:checkable="true"
+            android:text="@string/cholesterol"
+            card_view:chipIcon="@drawable/cardv_grey_bg"
+            card_view:layout_constraintBottom_toBottomOf="parent"
+            card_view:layout_constraintEnd_toEndOf="parent"
+            card_view:layout_constraintStart_toStartOf="parent"
+            card_view:layout_constraintTop_toBottomOf="@+id/all_patient_txt_name" />
+
+        <com.google.android.material.chip.Chip
+            android:id="@+id/blood_pressure_chip"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="25dp"
+            android:layout_marginTop="8dp"
+            android:layout_marginEnd="100dp"
+            android:checkable="true"
+            android:text="@string/blood_pressure"
+            card_view:chipIcon="@drawable/cardv_grey_bg"
+            card_view:layout_constraintEnd_toEndOf="parent"
+            card_view:layout_constraintStart_toEndOf="@+id/cholesterol_chip"
+            card_view:layout_constraintTop_toBottomOf="@+id/all_patient_txt_name" />
+
+
+    </androidx.constraintlayout.widget.ConstraintLayout>
+
+
+</androidx.cardview.widget.CardView>
\ No newline at end of file

+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <include
+        android:id="@+id/select_patients_toolbar"
+        layout = "@layout/toolbar"/>
+
+
+    <TextView
+        android:id="@+id/select_patients_txt_loading"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:text="@string/loading_patients"
+        android:textSize="20sp"
+        android:layout_marginStart="8dp"
+        android:layout_marginTop="8dp"
+        android:layout_marginEnd="8dp"
+        android:layout_marginBottom="8dp"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@id/select_patients_toolbar"
+        app:layout_constraintVertical_bias="0"/>
+    
+    <ProgressBar
+        android:id="@+id/select_patients_progressBar"
+        style="?android:attr/progressBarStyleLarge"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_centerHorizontal="true"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@id/select_patients_toolbar"
+        />
+
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/select_patients_recycler_view"
+        android:layout_width="0dp"
+        android:layout_height="0dp"
+        android:layout_marginStart="8dp"
+        android:layout_marginTop="8dp"
+        android:layout_marginEnd="8dp"
+        android:layout_marginBottom="8dp"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintHorizontal_bias="0.0"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/select_patients_toolbar"
+        app:layout_constraintVertical_bias="0.0" />
+</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file

+<?xml version="1.0" encoding="utf-8"?>
+<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    xmlns:card_view="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/card_layout"
+    android:foreground="?selectableItemBackground"
+    card_view:cardBackgroundColor="@color/color_accent"
+    card_view:cardCornerRadius="12dp"
+    card_view:cardElevation="3dp"
+    android:layout_margin="5dp"
+    >
+
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:id="@+id/card_backgroud"
+        android:layout_width="match_parent"
+        android:layout_height="94dp">
+
+
+        <LinearLayout
+            android:id="@+id/linear_layout"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            card_view:layout_constraintBottom_toBottomOf="parent"
+            card_view:layout_constraintEnd_toStartOf="@id/guideline2"
+            card_view:layout_constraintHorizontal_bias="0"
+            card_view:layout_constraintStart_toStartOf="parent"
+            card_view:layout_constraintTop_toTopOf="parent"
+            card_view:layout_constraintVertical_bias="0.5">
+
+            <CheckBox
+                android:id="@+id/checkBox"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:theme="@style/checkBoxStyle"
+                android:visibility="gone" />
+
+        </LinearLayout>
+
+
+        <TextView
+            android:id="@+id/all_patient_txt_name"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:text="@string/patient_name"
+            android:textSize="25sp"
+            card_view:layout_constraintBottom_toBottomOf="@id/linear_layout"
+            card_view:layout_constraintEnd_toStartOf="@id/guideline2"
+            card_view:layout_constraintHorizontal_bias="0.0"
+            card_view:layout_constraintStart_toEndOf="@id/guideline"
+            card_view:layout_constraintTop_toTopOf="parent"
+            card_view:layout_constraintVertical_bias="0.285" />
+
+        <androidx.constraintlayout.widget.Guideline
+            android:id="@+id/guideline"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            card_view:layout_constraintGuide_percent="0.04" />
+
+        <androidx.constraintlayout.widget.Guideline
+            android:id="@+id/guideline2"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            card_view:layout_constraintGuide_percent="0.96" />
+
+        <com.google.android.material.chip.Chip
+            android:id="@+id/cholesterol_chip"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="45dp"
+            android:layout_marginTop="8dp"
+            android:layout_marginEnd="267dp"
+            android:checkable="true"
+            android:text="@string/cholesterol"
+            card_view:chipIcon="@drawable/cardv_grey_bg"
+            card_view:layout_constraintBottom_toBottomOf="parent"
+            card_view:layout_constraintEnd_toEndOf="parent"
+            card_view:layout_constraintStart_toStartOf="parent"
+            card_view:layout_constraintTop_toBottomOf="@+id/all_patient_txt_name" />
+
+        <com.google.android.material.chip.Chip
+            android:id="@+id/blood_pressure_chip"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="25dp"
+            android:layout_marginTop="8dp"
+            android:layout_marginEnd="100dp"
+            android:checkable="true"
+            android:text="@string/blood_pressure"
+            card_view:chipIcon="@drawable/cardv_grey_bg"
+            card_view:layout_constraintEnd_toEndOf="parent"
+            card_view:layout_constraintStart_toEndOf="@+id/cholesterol_chip"
+            card_view:layout_constraintTop_toBottomOf="@+id/all_patient_txt_name" />
+
+
+    </androidx.constraintlayout.widget.ConstraintLayout>
+
+
+</androidx.cardview.widget.CardView>
\ No newline at end of file

+<?xml version="1.0" encoding="utf-8"?>
+<androidx.appcompat.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:background="@color/colorPrimary"
+    android:elevation="6dp"
+    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
+    app:popupTheme="@style/ThemeOverlay.AppCompat.Light">
+
+    <RelativeLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content">
+
+        <ImageButton
+            android:id="@+id/btn_back"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:background="@android:color/transparent"
+            android:src="@drawable/ic_arrow_back_24dp"
+            android:layout_centerVertical="true"
+            android:layout_marginRight="20dp"
+            />
+
+        <TextView
+            android:id="@+id/toolbar_title"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_toRightOf="@id/btn_back"
+            android:text="Title Here"
+            android:textSize="23sp"
+            android:textColor="@color/color_white"
+            android:layout_centerVertical="true">
+        </TextView>
+
+    </RelativeLayout>
+
+</androidx.appcompat.widget.Toolbar>
\ No newline at end of file

+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+    <item
+        android:id="@+id/patient_add"
+        app:showAsAction="always"
+        android:title="@string/start_monitoring" />
+
+</menu>

@@ -368,4 +368,6 @@
     <string name="string_check_date">检查日期:</string>
     <string name="string_examination_doctor">检查医生:</string>
 
+
+
 </resources>
\ No newline at end of file

@@ -61,6 +61,10 @@
     <color name="color_4f4f4f">#4F4F4F</color>
     <color name="color_565656">#565656</color>
     <color name="color_737373">#737373</color>
-
+    <color name="color_accent">#E0E9FF</color>
+    <color name="color_accent_text">#35375A</color>
+    <color name="color_selected_patient">#bedec5</color>
+    <color name="unselected">#8c92ac</color>
+    <color name="colorPrimary">#5C4AE4</color>
 
 </resources>
\ No newline at end of file

@@ -388,4 +388,12 @@
     <string name="normal_mode">标定模式</string>
     <string name="single_mode">单帧模式</string>
 
+    <string name="loading_patients">Loading Patients…</string>
+    <string name="patient_name">Patient Name</string>
+    <string name="cholesterol">cholesterol</string>
+    <string name="blood_pressure">blood pressure</string>
+    <string name="zero_patients_message">You have 0 patients</string>
+    <string name="title_patient_selection">Select Patients</string>
+    <string name="start_monitoring">Start</string>
+
 </resources>
\ No newline at end of file

@@ -53,4 +53,9 @@
         <item name="colorControlActivated">@color/color_42bf58</item>
     </style>
 
+    <style name="checkBoxStyle" parent="Base.Theme.AppCompat">
+        <item name="colorAccent">@color/color_accent_text</item>
+        <item name="android:textColorSecondary">@color/color_accent_text</item>
+    </style>
+
 </resources>
\ No newline at end of file