Refactor of timer logic,

initial progress made on SleepLog functionality(storing, displaying sleep data)
Back button now works returning from settings to main view

app/build.gradle

@@ -6,7 +6,7 @@ android {
 
     defaultConfig {
         applicationId "com.example.sleeplog"
-        minSdkVersion 16
+        minSdkVersion 28
         targetSdkVersion 29
         versionCode 1
         versionName "1.0"

app/src/main/java/com/example/sleeplog/LogEntry.java

@@ -0,0 +1,18 @@
+package com.example.sleeplog;
+
+public class LogEntry {
+    private SleepSession _sleepSession;
+
+    public LogEntry(SleepSession sleepSession) {
+        _sleepSession = sleepSession;
+    }
+
+    public SleepSession get_sleepSession() {
+        return _sleepSession;
+    }
+
+    //Outputs the ByteArray needed to write to SleepLog.txt
+//    public byte[] toByteArray(){
+//        return _sleepSession.get();
+//    }
+}

app/src/main/java/com/example/sleeplog/MainActivity.java

@@ -1,9 +1,7 @@
 package com.example.sleeplog;
 
-import android.content.Context;
 import android.content.Intent;
 import android.os.Handler;
-import android.os.SystemClock;
 //import android.support.v7.app.AppCompactActivity;
 import android.os.Bundle;
 import android.view.View;
@@ -13,21 +11,45 @@
 import androidx.appcompat.app.AppCompatActivity;
 
 import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.time.Duration;
+import java.time.LocalDateTime;
+
+//TODO make unit tests for clock? Would maybe have to encapsulate clock logic for
+// tests.
 
 public class MainActivity extends AppCompatActivity {
 
     TextView timer ;
-    Button startButton, pauseButton, resetButton, stopAndLog, settingsButton;
-    long MillisecondTime, StartTime, TimeBuff, UpdateTime = 0L ;
+    Button startButton, pauseButton, resetButton, stopAndLog, settingsButton, sleepLogButton;
+    long MillisecondTime, TimeBuff, UpdateTime = 0L ;
+    LocalDateTime _startTime;
+    Duration _timeElapsed;
+    File _sleepLogFile;
+
     Handler handler;
-    int Seconds, Minutes, Hours ;
+    long Seconds, Minutes, _hours;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
+        //get internal file directory, points to/creates SleepLog file
+        //AppCompatActivity extends Context so we use it in File constructor param
+
+        _sleepLogFile = new File(this.getFilesDir(), "SleepLog.txt");
+
+//        FileOutputStream stream;
+//        try {
+//            stream = new FileOutputStream(_sleepLogFile);
+//            stream.write("HELLO WORLD".getBytes());
+//            stream.close();
+//        } catch (IOException e) {
+//            e.printStackTrace();
+//        }
+        //read
 
-        File _sleepLog = new File(this.getFilesDir(), "SleepLog");
 
 
 
@@ -37,14 +59,16 @@ protected void onCreate(Bundle savedInstanceState) {
         resetButton = (Button)findViewById(R.id.Reset);
         stopAndLog = (Button)findViewById(R.id.FinishedSleeping);
         settingsButton = (Button)findViewById(R.id.Settings);
+        sleepLogButton = (Button)findViewById(R.id.SleepLog);
+
 
         handler = new Handler() ;
 
         startButton.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View view) {
 
-                StartTime = SystemClock.uptimeMillis();
+                _startTime = LocalDateTime.now();
                 handler.postDelayed(runnable, 0);
 
                 resetButton.setEnabled(false);
@@ -55,8 +79,6 @@ public void onClick(View view) {
             @Override
             public void onClick(View view) {
 
-                TimeBuff += MillisecondTime;
-
                 handler.removeCallbacks(runnable);
 
                 resetButton.setEnabled(true);
@@ -67,49 +89,36 @@ public void onClick(View view) {
         resetButton.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View view) {
-
-                MillisecondTime = 0L ;
-                StartTime = 0L ;
-                TimeBuff = 0L ;
-                UpdateTime = 0L ;
-                Seconds = 0 ;
-                Minutes = 0 ;
-
                 timer.setText("00:00:00");
 
+                SleepSession sleepSession = new SleepSession(_startTime, LocalDateTime.now());
+                FileOutputStream stream;
+                try {
+                    stream = new FileOutputStream(_sleepLogFile);
+                    stream.write(sleepSession.get_byteArray());
+                    System.out.println("Wrote " + sleepSession.get_byteArray().toString() + " to SleepLog.txt");
+                    stream.close();
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
             }
         });
-        final Intent settings = new Intent(MainActivity.this, SettingsActivity.class);
-        settingsButton.setOnClickListener(view -> startActivity(settings));
-//        settingsButton.setOnClickListener(new View.OnClickListener() {
-//            @Override
-//            public void onClick(View view)
-//            {
-//               startActivity(settings);
-//
-//            }
-//        });
+
+        final Intent _settings = new Intent(MainActivity.this, SettingsActivity.class);
+        settingsButton.setOnClickListener(view -> startActivity(_settings));
+
+        final Intent _sleepLog = new Intent(MainActivity.this, SleepLogActivity.class);
+        sleepLogButton.setOnClickListener(view -> startActivity(_sleepLog));
     }
 
     public Runnable runnable = new Runnable() {
 
         public void run() {
 
-            MillisecondTime = SystemClock.uptimeMillis() - StartTime;
-
-            UpdateTime = TimeBuff + MillisecondTime;
-
-            Seconds = (int) (UpdateTime / 1000);
-
-            Hours = Seconds / 3600;
-
-            Minutes = Seconds / 60;
-
-            Seconds = Seconds % 60;
+            SleepSession sleepSession = new SleepSession(_startTime, LocalDateTime.now());
 
-            timer.setText("" + String.format("%02d", Hours) + ":" + String.format("%02d", Minutes)
-                    + ":" + String.format("%02d", Seconds));
+            timer.setText(sleepSession.toString());
 
             handler.postDelayed(this, 0);
         }
-    };}
+    };}

app/src/main/java/com/example/sleeplog/SettingsActivity.java

@@ -5,6 +5,10 @@
 import androidx.appcompat.app.AppCompatActivity;
 import android.widget.Button;
 
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.Scanner;
+
 public class SettingsActivity extends AppCompatActivity {
 
     Button button2, button3, button4;
@@ -14,7 +18,19 @@ protected void onCreate(Bundle savedInstanceState) {
         setContentView(R.layout.settings_main);
 
         button2 = (Button)findViewById(R.id.button2);
+
+        File _sleepLogFile = new File(this.getFilesDir(), "SleepLog.txt");
+        try {
+            Scanner myReader = new Scanner(_sleepLogFile);
+            String str = myReader.nextLine();
+            System.out.println(str);
+            button2.setText(str);
+        } catch (FileNotFoundException e) {
+            e.printStackTrace();
+        }
+
         button3 = (Button)findViewById(R.id.button3);
         button4 = (Button)findViewById(R.id.button4);
+
     }
 }

app/src/main/java/com/example/sleeplog/SleepLogActivity.java

@@ -0,0 +1,15 @@
+package com.example.sleeplog;
+
+import android.os.Bundle;
+
+import androidx.appcompat.app.AppCompatActivity;
+/*TODO implement SleepLogActivity, make it list "bedtime -> waketime: duration date of the night"
+   parse lines in txt, pass into new SleepSessions, send to Buttons in recyclerview.
+*/
+public class SleepLogActivity extends AppCompatActivity {
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.sleeplog_main);
+    }
+}

app/src/main/java/com/example/sleeplog/SleepSession.java

@@ -0,0 +1,64 @@
+package com.example.sleeplog;
+
+import java.time.Duration;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+
+public class SleepSession {
+    private Duration _sleepDuration;
+    private LocalDateTime _bedTime, _wakeTime;
+    private long _hours, _minutes, _seconds ;
+
+    public SleepSession(LocalDateTime bedTime, LocalDateTime wakeTime) {
+
+        _sleepDuration = Duration.between(bedTime, wakeTime);
+        _bedTime = bedTime;
+        _wakeTime = wakeTime;
+        _hours = (long)_sleepDuration.toHours();
+        _minutes = (long)_sleepDuration.minusHours(_seconds).toMinutes();
+        _seconds = (long)_sleepDuration.minusHours(_seconds).minusMinutes(_minutes).getSeconds();
+    }
+
+    public long get_hours() {
+        return _hours;
+    }
+
+    public long get_minutes() {
+        return _minutes;
+    }
+
+    public long get_seconds() {
+        return _seconds;
+    }
+
+//    public String get_bedTime() {
+//        return _bedTime.toString();
+//    }
+//
+//    public String get_wakeTime() {
+//        return _wakeTime.toString();
+//    }
+
+    public byte[] get_bedBytes() {
+        return _bedTime.toString().getBytes();
+    }
+
+    public byte[] get_wakeBytes() {
+        return _wakeTime.toString().getBytes();
+    }
+
+    public byte[] get_byteArray() {
+        return (_bedTime.toString() + _wakeTime.toString()).getBytes();
+    }
+
+    @Override
+    public String toString() {
+        return String.format("%02d", _hours) + ":" + String.format("%02d", _minutes)
+                + ":" + String.format("%02d", _seconds);
+    }
+
+    public static SleepSession parse(String text) {
+        //substring it
+        return new SleepSession(LocalDateTime.parse(text), LocalDateTime.parse(text));
+    }
+}

app/src/main/res/layout/activity_main.xml

@@ -74,7 +74,17 @@
         app:layout_constraintHorizontal_bias="0.95"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
-    <!--        tools:layout_editor_absoluteY="3dp" />-->
+
+    <Button
+        android:id="@+id/SleepLog"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="16dp"
+        android:text="SleepLog"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintHorizontal_bias="0.05"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
 
 
 </androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/sleeplog_main.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <ScrollView
+        android:layout_width="479dp"
+        android:layout_height="835dp"
+        tools:layout_editor_absoluteX="3dp"
+        tools:layout_editor_absoluteY="-1dp">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical" >
+
+            <Button
+                android:id="@+id/button5"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"
+                android:text="Button" />
+        </LinearLayout>
+    </ScrollView>
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/navigation/nav_graph.xml

@@ -3,7 +3,7 @@
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/nav_graph"
-    app:startDestination="@id/FirstFragment">
+    app:startDestination="@id/mainActivity">
 
     <fragment
         android:id="@+id/FirstFragment"
@@ -25,4 +25,20 @@
             android:id="@+id/action_SecondFragment_to_FirstFragment"
             app:destination="@id/FirstFragment" />
     </fragment>
+    <activity
+        android:id="@+id/mainActivity"
+        android:name="com.example.sleeplog.MainActivity"
+        android:label="MainActivity" >
+        <action
+            android:id = "@+id/action_mainActivity_to_settingsActivity"
+            app:destination="@+id/settingsActivity" />
+    </activity>
+    <activity
+        android:id="@+id/settingsActivity"
+        android:name="com.example.sleeplog.SettingsActivity"
+        android:label="SettingsActivity" >
+        <action
+            android:id = "@+id/action_settingsActivity_to_mainActivity"
+            app:destination="@+id/mainActivity" />
+    </activity>
 </navigation>