Ensure examples behave on default backend and/or with no local Bt device

This patch fixes crashes and ensures that examples give some form of
indication why they are not working.

Change-Id: Id99951e8729c0715505e5fff7448a475979a6406
Reviewed-by: Nedim Hadzic <nhadzic@blackberry.com>
Reviewed-by: Aaron McCarthy <mccarthy.aaron@gmail.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>

3 files changed, 19 insertions, 4 deletions

diff --git a/examples/bluetooth/btfiletransfer/remoteselector.cpp b/examples/bluetooth/btfiletransfer/remoteselector.cpp
index 53bf47f3..84619a4e 100644
--- a/examples/bluetooth/btfiletransfer/remoteselector.cpp
+++ b/examples/bluetooth/btfiletransfer/remoteselector.cpp
@@ -117,9 +117,14 @@ void RemoteSelector::startDiscovery(const QBluetoothUuid &uuid)
     m_discoveryAgent->setUuidFilter(uuid);
     m_discoveryAgent->start();
 
-    ui->status->setText(tr("Scanning..."));
-    ui->busyWidget->show();
-    ui->busyWidget->movie()->start();
+    if (!m_discoveryAgent->isActive() ||
+            m_discoveryAgent->error() != QBluetoothServiceDiscoveryAgent::NoError) {
+        ui->status->setText(tr("Cannot find remote services."));
+    } else {
+        ui->status->setText(tr("Scanning..."));
+        ui->busyWidget->show();
+        ui->busyWidget->movie()->start();
+    }
 }
 
 QBluetoothServiceInfo RemoteSelector::service() const
diff --git a/examples/bluetooth/picturetransfer/DeviceDiscovery.qml b/examples/bluetooth/picturetransfer/DeviceDiscovery.qml
index 1da77975..77391ec2 100644
--- a/examples/bluetooth/picturetransfer/DeviceDiscovery.qml
+++ b/examples/bluetooth/picturetransfer/DeviceDiscovery.qml
@@ -79,6 +79,14 @@ Item {
 //! [Discovery-2]
         model: BluetoothDiscoveryModel {
             discoveryMode: BluetoothDiscoveryModel.DeviceDiscovery
+            onErrorChanged: {
+                if (error == BluetoothDiscoveryModel.NoError)
+                    return;
+                if (error == BluetoothDiscoveryModel.PoweredOffError)
+                    titleLabel.text = "Bluetooth turned off";
+                else
+                    titleLabel.text = "Cannot find devices";
+            }
         }
 
         delegate: Button {
diff --git a/src/bluetooth/qbluetoothservicediscoveryagent_p.cpp b/src/bluetooth/qbluetoothservicediscoveryagent_p.cpp
index 513d7ea7..86874a6c 100644
--- a/src/bluetooth/qbluetoothservicediscoveryagent_p.cpp
+++ b/src/bluetooth/qbluetoothservicediscoveryagent_p.cpp
@@ -45,7 +45,9 @@
 QT_BEGIN_NAMESPACE
 
 QBluetoothServiceDiscoveryAgentPrivate::QBluetoothServiceDiscoveryAgentPrivate(const QBluetoothAddress &deviceAdapter)
-    :  error(QBluetoothServiceDiscoveryAgent::NoError), state(Inactive)
+    :  error(QBluetoothServiceDiscoveryAgent::NoError), state(Inactive),
+       deviceDiscoveryAgent(0), mode(QBluetoothServiceDiscoveryAgent::MinimalDiscovery),
+       singleDevice(false)
 {
     Q_UNUSED(deviceAdapter);
 }