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<td >Qt 5.12</td><td ><a href="qtbluetooth-index.html">Qt Bluetooth</a></td><td >Bluetooth QML Chat Example</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right"><a href="qtbluetooth-index.html">Qt 5.12.6 Reference Documentation</a></td>
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<h3><a name="toc">Contents</a></h3>
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<li class="level1"><a href="#running-the-example">Running the Example</a></li>
<li class="level1"><a href="#interacting-with-the-server">Interacting with the Server</a></li>
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<h1 class="title">Bluetooth QML Chat Example</h1>
<span class="subtitle"></span>
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<p>An example demonstrating communication through Bluetooth QML API.</p>
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<div class="descr"> <a name="details"></a>
<p><i>Bluetooth QML Chat</i> example shows how to use the <a href="qtbluetooth-index.html">Qt Bluetooth</a> QML API to communicate with another application on a remote device using Bluetooth.</p>
<p class="centerAlign"><img src="images/chat-view.png" alt="" /></p><p>The Bluetooth QML Chat example implements a simple chat program between two parties. The application acts as client and attempts to connect to a Bluetooth socket server. It uses the <a href="qml-qtbluetooth-bluetoothdiscoverymodel.html">BluetoothDiscoveryModel</a> type to find the server and <a href="qml-qtbluetooth-bluetoothsocket.html">BluetoothSocket</a> type to facilitate the data exchange.</p>
<a name="running-the-example"></a>
<h2 id="running-the-example">Running the Example</h2>
<p>To run the example from Qt Creator, open the <b>Welcome</b> mode and select the example from <b>Examples</b>. For more information, visit Building and Running an Example.</p>
<p>The example only works in connection with the <a href="qtbluetooth-btchat-example.html">Bluetooth Chat Example</a>. The Bluetooth Chat example launches the chat service and advertises it via the Bluetooth SDP protocol. It is important that the device running the Bluetooth Chat example actively advertises its SDP services. This can be checked using the <a href="qbluetoothlocaldevice.html#hostMode">QBluetoothLocalDevice::hostMode</a> property.</p>
<a name="interacting-with-the-server"></a>
<h2 id="interacting-with-the-server">Interacting with the Server</h2>
<p>The example application immediately starts the service discovery using the <a href="qml-qtbluetooth-bluetoothdiscoverymodel.html">BluetoothDiscoveryModel</a> type:</p>
<pre class="qml">
BluetoothDiscoveryModel {
id: btModel
running: true
discoveryMode: BluetoothDiscoveryModel.FullServiceDiscovery
uuidFilter: targetUuid //e8e10f95-1a70-4b27-9ccf-02010264e9c8
}
</pre>
<p>The <a href="qml-qtbluetooth-bluetoothdiscoverymodel.html#uuidFilter-prop">uuidFilter</a> property is used to only search for the chat server UUID and the <a href="qml-qtbluetooth-bluetoothdiscoverymodel.html#running-prop">running</a> property activates the search. Once a service with a matching UUID is found the model emits the <a href="qml-qtbluetooth-bluetoothdiscoverymodel.html#serviceDiscovered-signal">serviceDiscovered(BluetoothService)</a> signal.</p>
<pre class="qml">
onServiceDiscovered: {
if (serviceFound)
return
serviceFound = true
console.log("Found new service " + service.deviceAddress + " " + service.deviceName + " " + service.serviceName);
searchBox.appendText("\nConnecting to server...")
remoteDeviceName = service.deviceName
socket.setService(service)
}
</pre>
<p>The <a href="qml-qtbluetooth-bluetoothservice.html">BluetoothService</a> type encapsulates the details of the found chat server, such as the <a href="qml-qtbluetooth-bluetoothservice.html#serviceName-prop">name</a> and <a href="qml-qtbluetooth-bluetoothservice.html#serviceDescription-prop">description</a> of the service, as well as the <a href="qml-qtbluetooth-bluetoothservice.html#deviceName-prop">name</a> and <a href="qml-qtbluetooth-bluetoothservice.html#deviceAddress-prop">address</a> of the Bluetooth device offering the chat server. It is passed to the <a href="qml-qtbluetooth-bluetoothsocket.html">BluetoothSocket</a> to establish the connection.</p>
<p>Once the connection is established the socket's state is managed as follows:</p>
<pre class="qml">
BluetoothSocket {
id: socket
connected: true
onSocketStateChanged: {
switch (socketState) {
case BluetoothSocket.Unconnected:
case BluetoothSocket.NoServiceSet:
searchBox.animationRunning = false;
searchBox.setText("\nNo connection. \n\nPlease restart app.");
top.state = "begin";
break;
case BluetoothSocket.Connected:
console.log("Connected to server ");
top.state = "chatActive"; // move to chat UI
break;
case BluetoothSocket.Connecting:
case BluetoothSocket.ServiceLookup:
case BluetoothSocket.Closing:
case BluetoothSocket.Listening:
case BluetoothSocket.Bound:
break;
}
}
//...
}
</pre>
<p>The payload is received via the <a href="qml-qtbluetooth-bluetoothsocket.html#stringData-prop">stringData</a> property:</p>
<pre class="qml">
onStringDataChanged: {
console.log("Received data: " )
var data = remoteDeviceName + ": " + socket.stringData;
data = data.substring(0, data.indexOf('\n'))
chatContent.append({content: data})
}
</pre>
<p>And sent by setting the same property:</p>
<pre class="qml">
socket.stringData = data
</pre>
<p>Files:</p>
<ul>
<li><a href="qtbluetooth-chat-button-qml.html">chat/Button.qml</a></li>
<li><a href="qtbluetooth-chat-inputbox-qml.html">chat/InputBox.qml</a></li>
<li><a href="qtbluetooth-chat-search-qml.html">chat/Search.qml</a></li>
<li><a href="qtbluetooth-chat-chat-pro.html">chat/chat.pro</a></li>
<li><a href="qtbluetooth-chat-chat-qml.html">chat/chat.qml</a></li>
<li><a href="qtbluetooth-chat-chat-qrc.html">chat/chat.qrc</a></li>
<li><a href="qtbluetooth-chat-qmlchat-cpp.html">chat/qmlchat.cpp</a></li>
</ul>
<p>Images:</p>
<ul>
<li><a href="images/used-in-examples/chat/images/clear.png">chat/images/clear.png</a></li>
<li><a href="images/used-in-examples/chat/images/default.png">chat/images/default.png</a></li>
<li><a href="images/used-in-examples/chat/images/lineedit-bg.png">chat/images/lineedit-bg.png</a></li>
</ul>
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