Skip host lookup on Android

src/QtLocationPlugin/QGCTileCacheWorker.cpp

@@ -1094,15 +1094,40 @@ QGCCacheWorker::_createDB(QSqlDatabase* db, bool createDefault)
 void
 QGCCacheWorker::_testInternet()
 {
+    /*
+        To test if you have Internet connection, the code tests a connection to
+        8.8.8.8:53 (google DNS). It appears that some routers are now blocking TCP
+        connections to port 53. So instead, we use a TCP connection to "github.com"
+        (80). On exit, if the look up for “github.com” is under way, a call to abort
+        the lookup is made. This abort call on Android has no effect, and the code
+        blocks for a full minute. So to work around the issue, we continue a direct
+        TCP connection to 8.8.8.8:53 on Android and do the lookup/connect on the
+        other platforms.
+    */
+#if defined(__android__)
+    QTcpSocket socket;
+    socket.connectToHost("8.8.8.8", 53);
+    if (socket.waitForConnected(2000)) {
+        qCDebug(QGCTileCacheLog) << "Yes Internet Access";
+        emit internetStatus(true);
+        return;
+    }
+    qWarning() << "No Internet Access";
+    emit internetStatus(false);
+#else
     if(!_hostLookupID) {
         _hostLookupID = QHostInfo::lookupHost("www.github.com", this, SLOT(_lookupReady(QHostInfo)));
     }
+#endif
 }
 
 //-----------------------------------------------------------------------------
 void
 QGCCacheWorker::_lookupReady(QHostInfo info)
 {
+#if defined(__android__)
+    Q_UNUSED(info);
+#else
     _hostLookupID = 0;
     if(info.error() == QHostInfo::NoError && info.addresses().size()) {
         QTcpSocket socket;
@@ -1118,4 +1143,5 @@ QGCCacheWorker::_lookupReady(QHostInfo info)
     }
     qWarning() << "No Internet Access";
     emit internetStatus(false);
+#endif
 }