Añadido boton de guardado y comienzo de interfaz de guardado en archivo físico

app/src/main/java/com/journaldev/gpslocationtracking/FIleManager.java

@@ -0,0 +1,51 @@
+package com.journaldev.gpslocationtracking;
+
+import android.content.Context;
+import android.util.Log;
+
+import java.io.*;
+
+public class FIleManager {
+
+
+    public void writeToFile(String data, Context context) {
+        try {
+            OutputStreamWriter outputStreamWriter = new OutputStreamWriter(context.openFileOutput("coordenadas.txt", Context.MODE_PRIVATE));
+            outputStreamWriter.write(data);
+            outputStreamWriter.close();
+        }
+        catch (IOException e) {
+            Log.e("Exception", "File write failed: " + e.toString());
+        }
+    }
+
+    private String readFromFile(Context context) {
+
+        String ret = "";
+
+        try {
+            InputStream inputStream = context.openFileInput("coordenadas.txt");
+
+            if ( inputStream != null ) {
+                InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
+                BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
+                String receiveString = "";
+                StringBuilder stringBuilder = new StringBuilder();
+
+                while ( (receiveString = bufferedReader.readLine()) != null ) {
+                    stringBuilder.append("\n").append(receiveString);
+                }
+
+                inputStream.close();
+                ret = stringBuilder.toString();
+            }
+        }
+        catch (FileNotFoundException e) {
+            Log.e("login activity", "File not found: " + e.toString());
+        } catch (IOException e) {
+            Log.e("login activity", "Can not read file: " + e.toString());
+        }
+
+        return ret;
+    }
+}

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

@@ -10,6 +10,13 @@
     android:paddingTop="@dimen/activity_vertical_margin"
     tools:context="com.journaldev.gpslocationtracking.MainActivity">
 
+    <Button
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:id="@+id/btn2"
+            android:text="Save Data"
+            android:layout_centerHorizontal="true" android:layout_alignParentBottom="true"
+            android:layout_marginBottom="153dp"/>
     <Button
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"