move due checking to asynctask

previously it fail to retreive any book from internet in android 4
also make exception handing more explicit
and add log message

app/src/main/AndroidManifest.xml

@@ -28,7 +28,9 @@
                 android:value=".MainActivity" />
         </activity>
 
-        <receiver android:name=".DueChecker" />
+        <receiver android:name=".DueChecker"
+                 android:permission="android.permission.INTERNET"
+                 />
     </application>
 
 </manifest>

app/src/main/java/com/loopbook/cuhk_loopbook/CheckSched.java

@@ -8,6 +8,8 @@
 import android.widget.Toast;
 import android.content.Context;
 
+import android.util.Log;
+
 public class CheckSched {
     public static void scheduleNotification(Context context) {
         Intent notificationIntent = new Intent(context, DueChecker.class);
@@ -17,11 +19,13 @@ public static void scheduleNotification(Context context) {
         Calendar calendar = Calendar.getInstance();
 
         if (BuildInfo.DEBUG) {
+            Log.e("CheckSched", "scheduling in debugmode");
             calendar.setTimeInMillis(System.currentTimeMillis() + 5000);
             alarmMgr.setInexactRepeating(
                     AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
                     AlarmManager.INTERVAL_FIFTEEN_MINUTES, pendingIntent);
         } else {
+            Log.e("CheckSched", "scheduling in releasemode");
             // Set the alarm to start at approximately ?:??.
             calendar.setTimeInMillis(System.currentTimeMillis());
             calendar.set(Calendar.HOUR_OF_DAY, 15);

app/src/main/java/com/loopbook/cuhk_loopbook/DueChecker.java

@@ -6,27 +6,49 @@
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
+import android.os.AsyncTask;
 
 import java.util.*;
 import java.text.SimpleDateFormat;
 
 import org.jsoup.nodes.Element;
+import android.util.Log;
 
 public class DueChecker extends BroadcastReceiver {
     public static int notifyId = 1;
     public static int day_threshold = BuildInfo.DEBUG ? 20 : 2;
 
-    public void onReceive(Context context, Intent intent) {
-        boolean connectable = LibConn.isConnectable();
-        Element elm = null;
-        try {
+    private class AsyncBookLoader extends AsyncTask<Context, Void, Element> {
+        private Exception caughtException = null;
+        private Context context;
+
+        @Override
+        protected Element doInBackground(Context... context) {
+            Log.e("DueChecker", "doingInbackground");
+            Element elm;
+            this.context = context[0];
+            boolean connectable = LibConn.isConnectable();
             elm = connectable ?
-                DataIO.refreshStoredData(context) :
-                DataIO.getStoredData(context);
-        } catch (RuntimeException e) {
-            return;
+                DataIO.refreshStoredData(this.context) :
+                DataIO.getStoredData(this.context);
+
+            return elm;
+        }
+
+        @Override
+        protected void onPostExecute(Element elm) {
+            Log.e("DueChecker", "postexecute");
+            DueChecker.checker(context, elm);
         }
+    }
+
+    public void onReceive(Context context, Intent intent) {
+        Log.e("DueChecker", "onReceive");
+        AsyncBookLoader bookLoader = new AsyncBookLoader();
+        bookLoader.execute(context);
+    }
 
+    private static void checker(Context context, Element elm) {
         SimpleDateFormat dateparser = new SimpleDateFormat("dd-MM-yy");
         Calendar DaysLater = Calendar.getInstance();
         DaysLater.add(Calendar.DATE, day_threshold);
@@ -42,14 +64,14 @@ public void onReceive(Context context, Intent intent) {
 
             if (DaysLater.compareTo(dueDate) > 0) {
                 NotificationManager nManager = (NotificationManager)context
-                                               .getSystemService(Context.NOTIFICATION_SERVICE);
+                    .getSystemService(Context.NOTIFICATION_SERVICE);
                 NotificationCompat.Builder builder = getNotification(context, title);
                 nManager.notify(notifyId++, builder.build());
             }
         }
     }
 
-    private NotificationCompat.Builder getNotification(Context context, String content) {
+    public static NotificationCompat.Builder getNotification(Context context, String content) {
         NotificationCompat.Builder builder = new NotificationCompat.Builder(context);
         builder.setContentTitle("Book going to expire");
         builder.setContentText(content);

app/src/main/java/com/loopbook/cuhk_loopbook/LibConn.java

@@ -8,6 +8,7 @@
 import java.util.*;
 import java.net.InetAddress;
 
+import android.util.Log;
 
 public class LibConn {
     private final String name;
@@ -23,8 +24,10 @@ public LibConn(String name, String passwd) {
     public static boolean isConnectable() {
         try {
             InetAddress ipAddr = InetAddress.getByName("google.com");
+            Log.e("Libconn", "connectable");
             return !ipAddr.equals("");
         } catch (Exception e) {
+            Log.e("Libconn", "unconnectable");
             return false;
         }
 
@@ -40,7 +43,8 @@ public void login() {
         try {
             resp = conn.execute();
             doc = resp.parse();
-        } catch(Exception e) { 
+        } catch(java.io.IOException e) { 
+            Log.e("Libconn", "IOException");
             throw new RuntimeException("Failed connection", e); 
         }
 
@@ -50,13 +54,13 @@ public void login() {
         }
 
         //Element name = doc.select("strong").first();
-        try {
-            Element bookListLink = doc.select(".patroninfoList a").first();
-            this.bookhref = bookListLink.attr("abs:href");
-            this.cookies = resp.cookies();
-        } catch(Exception e) {
-            throw new RuntimeException("Cannnot get books after login", e);
-        }
+        Element bookListLink = doc.select(".patroninfoList a").first();
+        if (bookListLink == null)
+            throw new RuntimeException("Cannnot get books after login");
+        this.bookhref = bookListLink.attr("abs:href");
+        if (this.bookhref == "")
+            throw new RuntimeException("Cannnot get books after login");
+        this.cookies = resp.cookies();
     }
 
     public Element getBooksElement() {