Adding a way to see what's been logged, back button on FirstActivity still isn't right...

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

app/src/main/java/com/coldlightalchemist/interactivitystatesharingexample/Constants.java

@@ -0,0 +1,8 @@
+package com.coldlightalchemist.interactivitystatesharingexample;
+
+public class Constants {
+    public static final String kInterActivityStateKey = "Inter Activity State";
+    public static final String kFileName = "MyFile.csv";
+
+    public static final String[] kCSVHeaders = {"First Activity String", "Second Activity Int"};
+}

app/src/main/java/com/coldlightalchemist/interactivitystatesharingexample/FirstActivity.java

@@ -1,5 +1,7 @@
 package com.coldlightalchemist.interactivitystatesharingexample;
 
+import android.content.Context;
+import android.content.DialogInterface;
 import android.content.Intent;
 import android.os.Bundle;
 import android.text.Editable;
@@ -8,6 +10,8 @@ import android.widget.Button;
 import android.widget.EditText;
 
 import androidx.activity.EdgeToEdge;
+import androidx.activity.OnBackPressedCallback;
+import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.core.graphics.Insets;
 import androidx.core.view.ViewCompat;
@@ -32,7 +36,29 @@ public class FirstActivity extends AppCompatActivity {
             return insets;
         });
 
-        InterActivityState state = (InterActivityState) Objects.requireNonNull(getIntent().getExtras()).get(MainActivity.kInterActivityStateKey);
+        Context context = getApplicationContext();
+        InterActivityState state = (InterActivityState) Objects.requireNonNull(getIntent().getExtras()).get(Constants.kInterActivityStateKey);
+
+        this.getOnBackPressedDispatcher().addCallback(new OnBackPressedCallback(true) {
+            @Override
+            public void handleOnBackPressed() {
+                AlertDialog.Builder alertBuilder = new AlertDialog.Builder(context);
+                DialogInterface.OnClickListener listener = (d, w) -> {
+                    switch(w) {
+                        case DialogInterface.BUTTON_POSITIVE:
+                            finish();
+                            break;
+                        case DialogInterface.BUTTON_NEGATIVE:
+                            break;
+                    }
+                };
+
+                alertBuilder.setMessage("Are you sure you want to back out, the data you've entered so far will be lost!")
+                        .setPositiveButton("Yes", listener)
+                        .setNegativeButton("No", listener)
+                        .show();
+            }
+        });
 
         enterStringField = (EditText) findViewById(R.id.enterStringField);
         enterStringField.addTextChangedListener(new TextWatcher() {
@@ -56,7 +82,7 @@ public class FirstActivity extends AppCompatActivity {
         moveToSecondActivity = (Button) findViewById(R.id.moveToSecondActivity);
         moveToSecondActivity.setOnClickListener((v) -> {
             Intent secondActivityIntent = new Intent(v.getContext(), SecondActivity.class);
-            secondActivityIntent.putExtra(MainActivity.kInterActivityStateKey, state);
+            secondActivityIntent.putExtra(Constants.kInterActivityStateKey, state);
             startActivity(secondActivityIntent);
         });
 

app/src/main/java/com/coldlightalchemist/interactivitystatesharingexample/InterActivityState.java

@@ -9,9 +9,6 @@ import java.io.Serializable;
 import java.nio.file.Files;
 
 public class InterActivityState implements Serializable {
-
-    private static final String[] kCSVHeaders = {"First Activity String", "Second Activity Int"};
-
     private File writeFile;
     private String firstActivityString;
     private int secondActivityInt;
@@ -44,7 +41,7 @@ public class InterActivityState implements Serializable {
         PrintWriter writer = new PrintWriter(new FileWriter(writeFile, true));
 
         if (!fileExists) {
-            writer.println(Utilities.makeCSVString(kCSVHeaders));
+            writer.println(Utilities.makeCSVString(Constants.kCSVHeaders));
         }
 
         writer.println(Utilities.makeCSVString(firstActivityString, Integer.toString(secondActivityInt)));

app/src/main/java/com/coldlightalchemist/interactivitystatesharingexample/MainActivity.java

@@ -1,8 +1,13 @@
 package com.coldlightalchemist.interactivitystatesharingexample;
 
+import static android.view.View.INVISIBLE;
+import static android.view.View.VISIBLE;
+
 import android.content.Intent;
 import android.os.Bundle;
+import android.util.Log;
 import android.widget.Button;
+import android.widget.TextView;
 import android.widget.Toast;
 
 import androidx.activity.EdgeToEdge;
@@ -11,17 +16,27 @@ import androidx.appcompat.app.AppCompatActivity;
 import androidx.core.graphics.Insets;
 import androidx.core.view.ViewCompat;
 import androidx.core.view.WindowInsetsCompat;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
+
+import org.w3c.dom.Text;
 
 import java.io.File;
+import java.io.IOException;
 import java.nio.file.Paths;
+import java.util.List;
+import java.util.Map;
 
 public class MainActivity extends AppCompatActivity {
     private InterActivityState interActivityState;
 
     private Button startDataEntry;
 
-    public static final String kInterActivityStateKey = "Inter Activity State";
+    private TextView nothingInFile;
-    public static final String kFileName = "MyFile.csv";
+
+    private RecyclerView dataInFile;
+
+    private File dataFile;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -34,12 +49,41 @@ public class MainActivity extends AppCompatActivity {
             return insets;
         });
 
+        dataFile = new File(getFilesDir(), Constants.kFileName);
+
         startDataEntry = (Button) findViewById(R.id.startDataEntry);
         startDataEntry.setOnClickListener((v) -> {
-            interActivityState = new InterActivityState(new File(v.getContext().getFilesDir(), kFileName));
+            interActivityState = new InterActivityState(dataFile);
             Intent firstActivityIntent = new Intent(v.getContext(), FirstActivity.class);
-            firstActivityIntent.putExtra(kInterActivityStateKey, interActivityState);
+            firstActivityIntent.putExtra(Constants.kInterActivityStateKey, interActivityState);
             startActivity(firstActivityIntent);
         });
+
+        nothingInFile = (TextView) findViewById(R.id.nothingInFile);
+
+        dataInFile = (RecyclerView) findViewById(R.id.dataInFile);
+        dataInFile.setLayoutManager(new LinearLayoutManager(this));
+
+        try {
+            List<Map<String, String>> currentFileData = Utilities.readFormattedCSV(dataFile);
+
+            if (currentFileData == null || currentFileData.isEmpty()) {
+                nothingInFile.setVisibility(VISIBLE);
+                dataInFile.setVisibility(INVISIBLE);
+            } else {
+                nothingInFile.setVisibility(INVISIBLE);
+                dataInFile.setVisibility(VISIBLE);
+
+                Log.d("RECYCLER DATA", "Recycler Data Size: " + currentFileData.size());
+
+                StoredDataRecyclerViewAdapter adapter = new StoredDataRecyclerViewAdapter(currentFileData);
+                dataInFile.setAdapter(adapter);
+            }
+        } catch (IOException e) {
+            nothingInFile.setVisibility(VISIBLE);
+            dataInFile.setVisibility(INVISIBLE);
+            Log.d("FILE READ", "Failed to read the data file for some reason", e);
+        }
+
     }
 }

app/src/main/java/com/coldlightalchemist/interactivitystatesharingexample/SecondActivity.java

@@ -35,7 +35,7 @@ public class SecondActivity extends AppCompatActivity {
             return insets;
         });
 
-        InterActivityState state = (InterActivityState) Objects.requireNonNull(getIntent().getExtras()).get(MainActivity.kInterActivityStateKey);
+        InterActivityState state = (InterActivityState) Objects.requireNonNull(getIntent().getExtras()).get(Constants.kInterActivityStateKey);
 
         editNumber = (EditText) findViewById(R.id.editNumber);
         editNumber.addTextChangedListener(new TextWatcher() {

app/src/main/java/com/coldlightalchemist/interactivitystatesharingexample/StoredDataRecyclerViewAdapter.java

@@ -0,0 +1,65 @@
+package com.coldlightalchemist.interactivitystatesharingexample;
+
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import androidx.annotation.NonNull;
+import androidx.recyclerview.widget.RecyclerView;
+
+import java.util.List;
+import java.util.Map;
+
+public class StoredDataRecyclerViewAdapter extends RecyclerView.Adapter<StoredDataRecyclerViewAdapter.StoredDataRecyclerViewHolder> {
+    private final List<Map<String, String>> data;
+
+    public static class StoredDataRecyclerViewHolder extends RecyclerView.ViewHolder {
+        private final TextView rvFirstActivityString;
+        private final TextView rvSecondActivityInt;
+
+        public StoredDataRecyclerViewHolder(View itemView) {
+            super(itemView);
+
+            rvFirstActivityString = itemView.findViewById(R.id.rvFirstActivityString);
+            rvSecondActivityInt = itemView.findViewById(R.id.rvSecondActivityInt);
+        }
+
+        public TextView getFirstActivityStringTextView() {
+            return rvFirstActivityString;
+        }
+
+        public TextView getSecondActivityIntTextView() {
+            return rvSecondActivityInt;
+        }
+    }
+
+    public StoredDataRecyclerViewAdapter(List<Map<String, String>> data) {
+        this.data = data;
+    }
+
+    @NonNull
+    @Override
+    public StoredDataRecyclerViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+        View view = LayoutInflater.from(parent.getContext())
+                .inflate(R.layout.stored_data_recycler_view_item, parent, false);
+
+        return new StoredDataRecyclerViewHolder(view);
+    }
+
+    @Override
+    public void onBindViewHolder(@NonNull StoredDataRecyclerViewHolder holder, int position) {
+        holder.getFirstActivityStringTextView().setText(
+                data.get(position).get(Constants.kCSVHeaders[0])
+        );
+        holder.getSecondActivityIntTextView().setText(
+                data.get(position).get(Constants.kCSVHeaders[1])
+        );
+    }
+
+    @Override
+    public int getItemCount() {
+        return data.size();
+    }
+
+}

app/src/main/java/com/coldlightalchemist/interactivitystatesharingexample/Utilities.java

@@ -1,6 +1,12 @@
 package com.coldlightalchemist.interactivitystatesharingexample;
 
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
 import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
 import java.util.stream.Collectors;
 
 public class Utilities {
@@ -9,4 +15,25 @@ public class Utilities {
                 .map((s) -> "\"" + s + "\"")
                 .collect(Collectors.joining(","));
     }
+
+    public static List<Map<String, String>> readFormattedCSV(File toRead) throws IOException {
+        if (!toRead.exists()) {
+            return null;
+        }
+
+        BufferedReader reader = new BufferedReader(new FileReader(toRead));
+
+        return reader.lines()
+                .filter((s) -> !s.equals(makeCSVString(Constants.kCSVHeaders)))
+                .map((s) -> {
+                    String[] spliteration = s.split("\",\"");
+
+                    // TODO: If you were to add columns, this would need to be more dynamic then it is
+                    return Map.of(
+                            Constants.kCSVHeaders[0], spliteration[0].replace("\"", ""),
+                            Constants.kCSVHeaders[1], spliteration[1].replace("\"", "")
+                    );
+                })
+                .collect(Collectors.toList());
+    }
 }

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

@@ -29,6 +29,17 @@
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:text="Start Data Entry" />
+
+            <TextView
+                android:id="@+id/nothingInFile"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="THERE IS NOTHING IN THE DATA FILE!" />
+
+            <androidx.recyclerview.widget.RecyclerView
+                android:id="@+id/dataInFile"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent" />
         </LinearLayout>
     </ScrollView>
 </androidx.constraintlayout.widget.ConstraintLayout>

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

@@ -0,0 +1,50 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout 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">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="vertical">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="horizontal">
+
+            <TextView
+                android:id="@+id/textView7"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_weight="1"
+                android:text="First Activity String" />
+
+            <TextView
+                android:id="@+id/rvFirstActivityString"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_weight="1" />
+        </LinearLayout>
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="horizontal">
+
+            <TextView
+                android:id="@+id/textView9"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_weight="1"
+                android:text="Second Activity Int" />
+
+            <TextView
+                android:id="@+id/rvSecondActivityInt"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_weight="1" />
+        </LinearLayout>
+    </LinearLayout>
+</androidx.constraintlayout.widget.ConstraintLayout>