fix event info hiding after activity restore (closes #23), add comments

app/src/main/java/com/akdev/nofbeventscraper/EventAdapter.java

@@ -60,6 +60,10 @@ public class EventAdapter extends
         // Set item views based on your views and data model
         holder.text_view_event_name.setText(event.name);
 
+        /*
+         * initialize all text views with event information
+         * hide fields and image views if no information is available
+         */
         if (!event.location.equals("")) {
             holder.text_view_event_location.setText(event.location);
         } else {
@@ -86,7 +90,6 @@ public class EventAdapter extends
         }
 
 
-
         if (!event.description.equals("")) {
             holder.text_view_event_description.setText(event.description);
         } else {
@@ -120,13 +123,14 @@ public class EventAdapter extends
         };
         holder.image_view_event_location.setOnClickListener(location_click_listener);
         holder.text_view_event_location.setOnClickListener(location_click_listener);
+
         /*
          * Add to calendar button: launch calendar application with current event
          */
         holder.button_add_to_calendar.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View view) {
-
+                // calendar event intent expects epoch time format
                 Long start_epoch = dateTimeToEpoch(event.start_date);
                 Long end_epoch = dateTimeToEpoch(event.end_date);
 
@@ -163,7 +167,7 @@ public class EventAdapter extends
         });
 
         /*
-         * Image dialog
+         * Image preview click creates fullscreen dialog
          */
 
         View.OnClickListener listener = new View.OnClickListener() {
@@ -198,7 +202,6 @@ public class EventAdapter extends
                         });
 
 
-
             }
         };
         holder.image_view_event_image.setOnClickListener(listener);
@@ -212,6 +215,9 @@ public class EventAdapter extends
         return events.size();
     }
 
+    /**
+     * access item view elements via holder class
+     */
     public static class ViewHolder extends RecyclerView.ViewHolder {
 
         protected TextView text_view_event_name;

app/src/main/java/com/akdev/nofbeventscraper/FbEventScraper.java

@@ -163,6 +163,7 @@ public class FbEventScraper extends AsyncTask<Void, Void, Void> {
 
                 JSONObject reader = new JSONObject(json);
 
+                // get all fields from json event information
                 name = readFromJson(reader, "name");
                 start_date = parseToDate(readFromJson(reader, "startDate"));
                 end_date = parseToDate(readFromJson(reader, "endDate"));
@@ -170,6 +171,7 @@ public class FbEventScraper extends AsyncTask<Void, Void, Void> {
                 location = fixLocation(readFromJson(reader, "location"));
                 image_url = readFromJson(reader, "image");
 
+                // try to find a high-res image
                 try {
                     image_url = document.select("div[id=event_header_primary]")
                             .select("img").first().attr("src");
@@ -177,6 +179,7 @@ public class FbEventScraper extends AsyncTask<Void, Void, Void> {
                 }
 
             } catch (JSONException | NullPointerException e) {
+                // json event information mot found. get at least title and image
                 name = document.title();
                 description = scraper.main.get().getString(R.string.error_scraping);
                 try {
@@ -186,9 +189,6 @@ public class FbEventScraper extends AsyncTask<Void, Void, Void> {
                 }
             }
 
-
-
-
             this.event = new FbEvent(url, name, start_date, end_date, description, location, image_url);
 
         } catch (IOException e) {

app/src/main/java/com/akdev/nofbeventscraper/FbPageScraper.java

@@ -22,7 +22,7 @@ public class FbPageScraper extends AsyncTask<Void, Void, Void> {
     private FbScraper scraper;
     private int error;
     private String url;
-    private List<String> event_links = new ArrayList<String>();
+    private List<String> event_links = new ArrayList<>();
 
     /**
      * Constructor with reference to scraper to return results.
@@ -58,6 +58,9 @@ public class FbPageScraper extends AsyncTask<Void, Void, Void> {
                     throw new IOException();
                 }
 
+                /*
+                 * get all event id's from current url and add to the list
+                 */
                 String regex = "(/events/[0-9]*)(/\\?event_time_id=[0-9]*)?";
 
                 List<String> event_links_href = document
@@ -68,13 +71,16 @@ public class FbPageScraper extends AsyncTask<Void, Void, Void> {
                     this.event_links.add("https://www.facebook.com" + link);
                 }
 
+                /*
+                 * check if more events should scraped
+                 */
                 SharedPreferences shared_prefs = PreferenceManager
                         .getDefaultSharedPreferences(scraper.main.get());
 
                 int max = shared_prefs.getInt("page_event_max", 5);
 
                 if (event_links.size() < max) {
-
+                    // find "next page
                     try {
                         String next_url = document
                                 .getElementsByAttributeValueMatching("href", "has_more=1")

app/src/main/java/com/akdev/nofbeventscraper/FbScraper.java

@@ -14,15 +14,12 @@ import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-import static com.akdev.nofbeventscraper.FbEvent.createEventList;
-
 public class FbScraper {
 
-    protected List<FbEvent> events;
     protected List<AsyncTask> tasks;
+    protected WeakReference<MainActivity> main; // no context leak with WeakReference
     url_type_enum url_type = url_type_enum.EVENT;
     private String input_url;
-    protected WeakReference<MainActivity> main; // no context leak with WeakReference
 
     /**
      * Constructor with WeakReference to the main activity, to add events.
@@ -33,10 +30,18 @@ public class FbScraper {
     FbScraper(WeakReference<MainActivity> main, String input_url) {
         this.main = main;
         this.input_url = input_url;
-        this.events = createEventList();
         this.tasks = new ArrayList<>();
     }
 
+    /**
+     * Checks if valid URL,
+     * strips the facebook page id from the input link and create an URL that can be scraped from.
+     *
+     * @param url input URL
+     * @return new mbasic url that can be scraped for event id's
+     * @throws URISyntaxException    if page not found
+     * @throws MalformedURLException
+     */
     protected String getPageUrl(String url) throws URISyntaxException, MalformedURLException {
 
         // check for url format
@@ -48,10 +53,11 @@ public class FbScraper {
         Matcher matcher = pattern.matcher(url);
 
         if (matcher.find()) {
-
+            //only mbasic does have event ids displayed in HTML
             String url_prefix = "https://mbasic.facebook.com/";
             String url_suffix = "?v=events";
 
+            // create URL
             return url_prefix + matcher.group(3) + url_suffix;
 
         } else {
@@ -60,7 +66,7 @@ public class FbScraper {
     }
 
     /**
-     * Strips the facebook event link of the input url.
+     * Strips the facebook event link from the input event url.
      *
      * @param url input url
      * @return facebook event url String if one was found
@@ -98,12 +104,40 @@ public class FbScraper {
 
     }
 
+    /**
+     * cancel vestigial async tasks
+     */
+    void killAllTasks() {
+
+        if (!tasks.isEmpty()) {
+            for (AsyncTask task : tasks) {
+                try {
+                    task.cancel(true);
+                    task = null;
+                } catch (Exception e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+    }
+
+    /**
+     * start an EventScraper async task and add to tasks list
+     *
+     * @param event_url
+     */
     void scrapeEvent(String event_url) {
         FbEventScraper scraper = new FbEventScraper(this, event_url);
         tasks.add(scraper);
         scraper.execute();
     }
 
+    /**
+     * Callback for finished EventSCraper async task
+     *
+     * @param event Contains event information if scraping successful
+     * @param error resId for error message
+     */
     void scrapeEventResultCallback(FbEvent event, int error) {
 
         if (event != null) {
@@ -115,20 +149,10 @@ public class FbScraper {
     }
 
     /**
-     * cancel vestigial async tasks
+     * start a page scraper and add to list of tasks
+     *
+     * @param page_url
      */
-    void killAllTasks() {
-
-        try {
-            for (AsyncTask task : tasks) {
-                task.cancel(true);
-                task = null;
-            }
-        } catch (Exception e) {
-            e.printStackTrace();
-        }
-    }
-
     void scrapePage(String page_url) {
         FbPageScraper scraper = new FbPageScraper(this, page_url);
 
@@ -136,6 +160,12 @@ public class FbScraper {
         scraper.execute();
     }
 
+    /**
+     * Callback for page scraper async task
+     *
+     * @param event_urls List of event urls scraped from the event
+     * @param error      resId of error message if task list is empty
+     */
     protected void scrapePageResultCallback(List<String> event_urls, int error) {
 
         if (event_urls.size() > 0) {
@@ -153,8 +183,12 @@ public class FbScraper {
         }
     }
 
+    /**
+     * Start scraping input url
+     */
     void run() {
 
+        // check if input url is an event
         try {
             String event_url = getEventUrl(input_url);
             url_type = url_type_enum.EVENT;
@@ -165,7 +199,7 @@ public class FbScraper {
         } catch (URISyntaxException | MalformedURLException e) {
             url_type = url_type_enum.INVALID;
         }
-
+        // check if input url is a page
         try {
             String page_url = getPageUrl(input_url);
             url_type = url_type_enum.PAGE;
@@ -177,6 +211,6 @@ public class FbScraper {
         }
     }
 
-
+    // enum for storing url type in this class
     enum url_type_enum {EVENT, PAGE, INVALID}
 }

app/src/main/java/com/akdev/nofbeventscraper/IntentReceiver.java

@@ -1,11 +1,10 @@
 package com.akdev.nofbeventscraper;
 
-import androidx.appcompat.app.AppCompatActivity;
-
 import android.content.Intent;
-import android.net.Uri;
 import android.os.Bundle;
 
+import androidx.appcompat.app.AppCompatActivity;
+
 public class IntentReceiver extends AppCompatActivity {
 
     @Override

app/src/main/java/com/akdev/nofbeventscraper/MainActivity.java

@@ -5,7 +5,6 @@ import android.content.ClipboardManager;
 import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
-import android.net.Uri;
 import android.os.Bundle;
 import android.view.KeyEvent;
 import android.view.Menu;
@@ -65,17 +64,24 @@ public class MainActivity extends AppCompatActivity {
         return list;
     }
 
-    /**
+    /*
-     * Callback for Restoring data
+     * On resume from other activities, e.g. settings
      */
     @Override
     public void onResume() {
         super.onResume();
 
+        /*
+         * Clear events after saved events deleted from settings
+         */
+        if (getSavedEvents().isEmpty()) {
             events.clear();
-        events.addAll(getSavedEvents());
             adapter.notifyDataSetChanged();
+        }
 
+        /*
+         * Intent from IntentReceiver - read only once
+         */
         Intent intent = getIntent();
         String data = intent.getStringExtra("InputLink");
 
@@ -209,7 +215,7 @@ public class MainActivity extends AppCompatActivity {
     }
 
     /**
-     * launch the FbScraper asynchronous task with the current text in the input text field.
+     * launch the FbScraper with the current text in the input text field.
      */
     public void startScraping() {
 
@@ -222,6 +228,12 @@ public class MainActivity extends AppCompatActivity {
         scraper.run();
     }
 
+    /**
+     * manage Helper text on uri_input
+     *
+     * @param str What should be displayed
+     * @param error True if should be displayed as error
+     */
     public void input_helper(String str, boolean error) {
 
         if (str == null) {
@@ -255,14 +267,21 @@ public class MainActivity extends AppCompatActivity {
         // Inflate the menu; this adds items to the action bar if it is present.
         getMenuInflater().inflate(R.menu.menu_main, menu);
 
+        /*
+         * Display icons, restricted API, maybe find other solution?
+         */
         if (menu instanceof MenuBuilder) {
             MenuBuilder m = (MenuBuilder) menu;
-            //noinspection RestrictedApi
             m.setOptionalIconsVisible(true);
         }
         return true;
     }
 
+    /**
+     * Dispatch menu item to new activity
+     * @param item
+     * @return
+     */
     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
 

app/src/main/java/com/akdev/nofbeventscraper/SettingsActivity.java

@@ -1,20 +1,15 @@
 package com.akdev.nofbeventscraper;
 
 import android.content.SharedPreferences;
-import android.graphics.Color;
 import android.os.Bundle;
 import android.view.View;
-import android.widget.TextView;
-import android.widget.Toast;
 
 import androidx.appcompat.app.ActionBar;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.preference.Preference;
 import androidx.preference.PreferenceFragmentCompat;
-import androidx.preference.PreferenceManager;
 
 import com.google.android.material.snackbar.Snackbar;
-import com.google.gson.Gson;
 
 public class SettingsActivity extends AppCompatActivity {
 
@@ -37,6 +32,9 @@ public class SettingsActivity extends AppCompatActivity {
         public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
             setPreferencesFromResource(R.xml.root_preferences, rootKey);
 
+            /*
+             * reset events click action: delete saved events and display snackbar
+             */
             Preference button = findPreference("event_reset");
             if (button != null) {
                 button.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {