implement basic logging mechanism

      <map>

        <entry key="app/src/main/res/layout/activity_main.xml" value="0.15070921985815602" />

        <entry key="app/src/main/res/layout/fragment_home.xml" value="0.1" />

        <entry key="app/src/main/res/layout/fragment_log.xml" value="0.1" />

        <entry key="app/src/main/res/layout/fragment_notifications.xml" value="0.1" />

        <entry key="app/src/main/res/layout/log_item.xml" value="0.1" />

        <entry key="app/src/main/res/menu/bottom_nav_menu.xml" value="0.18125" />

        <entry key="app/src/main/res/menu/menu_logs.xml" value="0.14479166666666668" />

      </map>

    </option>

  </component>

import android.app.Application;

import org.torproject.artitoyvpn.ui.logging.LogObservable;

import org.torproject.artitoyvpn.vpn.VpnStatusObservable;

public class ArtiToyVPNApp extends Application {

    VpnStatusObservable vpnStatusObservable;

    LogObservable logObservable;

    @Override

    public void onCreate() {

        super.onCreate();

        vpnStatusObservable = VpnStatusObservable.getInstance();

        logObservable = LogObservable.getInstance();

    }

}

package org.torproject.artitoyvpn.ui.logging;

import android.content.Context;

import android.content.Intent;

import android.net.Uri;

import android.os.Bundle;

import android.view.LayoutInflater;

import android.view.Menu;

import android.view.MenuInflater;

import android.view.MenuItem;

import android.view.View;

import android.view.ViewGroup;

import android.widget.TextView;

import android.widget.Toast;

import androidx.annotation.NonNull;

import androidx.annotation.Nullable;

import androidx.core.content.FileProvider;

import androidx.fragment.app.Fragment;

import androidx.lifecycle.Observer;

import androidx.lifecycle.ViewModelProvider;

import androidx.recyclerview.widget.DividerItemDecoration;

import androidx.recyclerview.widget.LinearLayoutManager;

import androidx.recyclerview.widget.RecyclerView;

import org.torproject.artitoyvpn.R;

import org.torproject.artitoyvpn.databinding.FragmentLogBinding;

import org.torproject.artitoyvpn.utils.Utils;

import java.io.File;

import java.util.Locale;

public class LogFragment extends Fragment {

    private LogViewModel logViewModel;

    private FragmentLogBinding binding;

    private LogRecyclerViewAdapter recyclerViewAdapter;

    // duct tape st¥le

    private boolean showTimestamps = true;

    public View onCreateView(@NonNull LayoutInflater inflater,

                             ViewGroup container, Bundle savedInstanceState) {

        logViewModel =

                new ViewModelProvider(this).get(LogViewModel.class);

        LogObservable logViewModel = LogObservable.getInstance();

        binding = FragmentLogBinding.inflate(inflater, container, false);

        View root = binding.getRoot();

        final TextView textView = binding.textLogs;

        logViewModel.getText().observe(getViewLifecycleOwner(), new Observer<String>() {

        final RecyclerView logList = binding.logList;

        LinearLayoutManager layoutManager = new LinearLayoutManager(this.getContext());

        logList.setLayoutManager(layoutManager);

        recyclerViewAdapter = new LogRecyclerViewAdapter();

        logList.setAdapter(recyclerViewAdapter);

        DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(this.getContext(), layoutManager.getOrientation());

        logList.addItemDecoration(dividerItemDecoration);

        logViewModel.getLogListData().observe(getViewLifecycleOwner(), logItems -> recyclerViewAdapter.updateList(logItems));

        setHasOptionsMenu(true);

        return root;

    }

    @Override

            public void onChanged(@Nullable String s) {

                textView.setText(s);

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

        super.onCreateOptionsMenu(menu, inflater);

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

        menu.findItem(R.id.action_show_timestamps).setTitle(showTimestamps ?

                R.string.hide_timestamps : R.string.show_timestamps);

    }

        });

        return root;

    @Override

    public boolean onOptionsItemSelected(MenuItem item) {

        int id = item.getItemId();

        Context context = getContext();

        if (context == null) {

            return super.onOptionsItemSelected(item);

        }

        //noinspection SimplifiableIfStatement

        if (id == R.id.action_copy) {

            String logs = LogObservable.getInstance().getLogStrings(showTimestamps);

            Utils.writeTextToClipboard(context, logs);

            Toast.makeText(context.getApplicationContext(), getString(R.string.copied_to_clipboard), Toast.LENGTH_SHORT).show();

            return true;

        } else if (id == R.id.action_show_timestamps) {

            showTimestamps = !showTimestamps;

            recyclerViewAdapter.setShowTimeStamps(showTimestamps);

            item.setTitle(showTimestamps ? R.string.hide_timestamps : R.string.show_timestamps);

        }

        return super.onOptionsItemSelected(item);

    }

    @Override

    public void onDestroyView() {

        super.onDestroyView();

package org.torproject.artitoyvpn.ui.logging;

import android.text.format.DateFormat;

import org.torproject.artitoyvpn.utils.Utils;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Locale;

public class LogItem {

    public final String content;

    public final String timestamp;

    public LogItem(String timestamp, String content) {

        this.timestamp = timestamp;

        this.content = content.trim();

    }

    @Override

    public String toString() {

        return timestamp + " " + content;

    }

    public String toString(boolean showTimestamp) {

        String result = "";

        result += showTimestamp ? timestamp + " " : "";

        result += content;

        return result;

    }

}

package org.torproject.artitoyvpn.ui.logging;

import androidx.lifecycle.LiveData;

import androidx.lifecycle.MutableLiveData;

import androidx.lifecycle.ViewModel;

import org.torproject.artitoyvpn.utils.Utils;

import java.util.ArrayList;

import java.util.Locale;

public class LogObservable extends ViewModel {

    private final MutableLiveData<ArrayList<LogItem>> logListData;

    private static LogObservable instance;

    private LogObservable() {

        logListData = new MutableLiveData<>(new ArrayList<>());

    }

    public static LogObservable getInstance() {

        if (instance == null) {

            instance = new LogObservable();

        }

        return instance;

    }

    public void addLog(String log) {

        ArrayList<LogItem> list = logListData.getValue();

        if (list != null) {

            list.add(new LogItem(Utils.getFormattedDate(System.currentTimeMillis(), Locale.getDefault()), log));

            logListData.postValue(list);

        }

    }

    public String getLogStrings(boolean showTimestamp) {

        StringBuilder builder = new StringBuilder();

        ArrayList<LogItem> logItemArrayList = logListData.getValue();

        if (logItemArrayList == null) {

            return "";

        }

        for (LogItem item : logItemArrayList) {

            builder.append(item.toString(showTimestamp)).append("\n");

        }

        return builder.toString();

    }

    public LiveData<ArrayList<LogItem>> getLogListData() {

        return logListData;

    }

}

 No newline at end of file