I&#39;m trying to read NFC tags on my Android phone using the NFC module of Qt.

According to this [page][1], Qt will support NFC on Android starting from version 5.6. This version hasn&#39;t been released yet, so I built it from source, following the instructions on this [page][2], and installed it in Qt creator.

First step is to get the tag/card detection working and I&#39;m stuck there. My test application instantiates a `QNearFieldManager`, checks if NFC is available and connects slots to the signals `targetDetected` and `targetLost`.
The `QNearFieldManager::isAvailable` method reports that NFC is available (with Qt 5.5 it did not), but the signals `targetDetected`/`targetLost` are never fired.

Below is the code of my test application:

    #include &lt;QLabel&gt;
    #include &lt;QVBoxLayout&gt;
    
    #include &lt;QNearFieldManager&gt;
    #include &lt;QNearFieldTarget&gt;
    
    #include &lt;QDebug&gt;
    
    #include &quot;window.h&quot;
    
    Window::Window(QWidget *parent)
    : QWidget(parent)
    {
        nfcLabel_ = new QLabel(this);
    
        QVBoxLayout *mainLayout = new QVBoxLayout;
        mainLayout-&gt;addWidget(nfcLabel_, 1);
    
        setLayout(mainLayout);
    
        setSizePolicy(QSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed));
    
        setWindowTitle(tr(&quot;NFC Test&quot;));
    
        nfc_ = new QNearFieldManager(this);
        if (nfc_-&gt;isAvailable()) {
            nfcLabel_-&gt;setText(&quot;NFC available&quot;);
        } else {
            nfcLabel_-&gt;setText(&quot;NFC not available&quot;);
            qWarning() &lt;&lt; &quot;NFC not available&quot;;
        }

        nfc_-&gt;setTargetAccessModes(QNearFieldManager::NdefReadTargetAccess); // doesn&#39;t help
    
        nfc_-&gt;registerNdefMessageHandler(this, SLOT(handleNdefMessage(QNdefMessage,QNearFieldTarget*))); // doesn&#39;t help
    
        connect(nfc_, SIGNAL(targetDetected(QNearFieldTarget*)), this, SLOT(targetDetected(QNearFieldTarget*)));
        connect(nfc_, SIGNAL(targetLost(QNearFieldTarget*)), this, SLOT(targetLost(QNearFieldTarget*)));
    
        if (!nfc_-&gt;startTargetDetection()) {
            qWarning() &lt;&lt; &quot;NFC target detection could not be started&quot;;
        }
    }
    
    Window::~Window()
    {
        nfc_-&gt;stopTargetDetection();
    }
    
    void Window::targetDetected(QNearFieldTarget * /*target*/)
    {
        nfcLabel_-&gt;setText(&quot;Target detected&quot;);
    }
    
    void Window::targetLost(QNearFieldTarget *target)
    {
        nfcLabel_-&gt;setText(&quot;Target lost&quot;);
        target-&gt;deleteLater();
    }
    
    void Window::handleNdefMessage(const QNdefMessage &amp;/*message*/, QNearFieldTarget */*target*/)
    {
        qDebug() &lt;&lt; &quot;Ndef Message&quot;;
    }
    

I must be missing something...

**UPDATE 1**

It appears that the AndroidManifest.xml file needs to be modified. I tried different things, but none seem to produce the desired effect. I can only get the `targetDetected` and `targetLost` events to fire when the manifest defines an intent-filter like this:

    &lt;intent-filter&gt;
        &lt;action android:name=&quot;android.nfc.action.TAG_DISCOVERED&quot;/&gt;
        &lt;category android:name=&quot;android.intent.category.DEFAULT&quot;/&gt;
    &lt;/intent-filter&gt;
    
However, this also causes the app to be started each time a target is scanned, even if the app is already running. What I need is to start the app and then wait for a target to be scanned. How can I accomplish this?

**UPDATE 2**

Below is the full AndroidManifest.xml file that I tried.

    &lt;?xml version=&quot;1.0&quot;?&gt;
    &lt;manifest package=&quot;org.qtproject.example&quot; xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot; android:versionName=&quot;1.0&quot; android:versionCode=&quot;1&quot; android:installLocation=&quot;auto&quot;&gt;
        &lt;application android:hardwareAccelerated=&quot;true&quot; android:name=&quot;org.qtproject.qt5.android.bindings.QtApplication&quot; android:label=&quot;-- %%INSERT_APP_NAME%% --&quot; android:theme=&quot;@android:style/Theme.Holo&quot;&gt;
        &lt;activity android:configChanges=&quot;orientation|uiMode|screenLayout|screenSize|smallestScreenSize|layoutDirection|locale|fontScale|keyboard|keyboardHidden|navigation&quot; android:name=&quot;org.qtproject.qt5.android.bindings.QtActivity&quot; android:label=&quot;-- %%INSERT_APP_NAME%% --&quot; android:screenOrientation=&quot;unspecified&quot; android:launchMode=&quot;singleTop&quot;&gt;
            &lt;intent-filter&gt;
            &lt;action android:name=&quot;android.intent.action.MAIN&quot;/&gt;
            &lt;category android:name=&quot;android.intent.category.LAUNCHER&quot;/&gt;
            &lt;/intent-filter&gt;
    
            &lt;!-- Without this, the targetDetected/targetLost signals aren&#39;t fired --&gt;
            &lt;intent-filter&gt;
            &lt;action android:name=&quot;android.nfc.action.TAG_DISCOVERED&quot;/&gt;
            &lt;category android:name=&quot;android.intent.category.DEFAULT&quot;/&gt;
            &lt;/intent-filter&gt;
    
            &lt;meta-data android:name=&quot;android.app.lib_name&quot; android:value=&quot;-- %%INSERT_APP_LIB_NAME%% --&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.qt_sources_resource_id&quot; android:resource=&quot;@array/qt_sources&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.repository&quot; android:value=&quot;default&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.qt_libs_resource_id&quot; android:resource=&quot;@array/qt_libs&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.bundled_libs_resource_id&quot; android:resource=&quot;@array/bundled_libs&quot;/&gt;
            &lt;!-- Deploy Qt libs as part of package --&gt;
            &lt;meta-data android:name=&quot;android.app.bundle_local_qt_libs&quot; android:value=&quot;-- %%BUNDLE_LOCAL_QT_LIBS%% --&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.bundled_in_lib_resource_id&quot; android:resource=&quot;@array/bundled_in_lib&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.bundled_in_assets_resource_id&quot; android:resource=&quot;@array/bundled_in_assets&quot;/&gt;
            &lt;!-- Run with local libs --&gt;
            &lt;meta-data android:name=&quot;android.app.use_local_qt_libs&quot; android:value=&quot;-- %%USE_LOCAL_QT_LIBS%% --&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.libs_prefix&quot; android:value=&quot;/data/local/tmp/qt/&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.load_local_libs&quot; android:value=&quot;-- %%INSERT_LOCAL_LIBS%% --&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.load_local_jars&quot; android:value=&quot;-- %%INSERT_LOCAL_JARS%% --&quot;/&gt;
            &lt;meta-data android:name=&quot;android.app.static_init_classes&quot; android:value=&quot;-- %%INSERT_INIT_CLASSES%% --&quot;/&gt;
            &lt;!--  Messages maps --&gt;
            &lt;meta-data android:value=&quot;@string/ministro_not_found_msg&quot; android:name=&quot;android.app.ministro_not_found_msg&quot;/&gt;
            &lt;meta-data android:value=&quot;@string/ministro_needed_msg&quot; android:name=&quot;android.app.ministro_needed_msg&quot;/&gt;
            &lt;meta-data android:value=&quot;@string/fatal_error_msg&quot; android:name=&quot;android.app.fatal_error_msg&quot;/&gt;
            &lt;!--  Messages maps --&gt;
    
            &lt;!-- Splash screen --&gt;
            &lt;!--
            &lt;meta-data android:name=&quot;android.app.splash_screen_drawable&quot; android:resource=&quot;@drawable/logo&quot;/&gt;
            --&gt;
            &lt;!-- Splash screen --&gt;
    
            &lt;!-- Background running --&gt;
            &lt;!-- Warning: changing this value to true may cause unexpected crashes if the
                  application still try to draw after
                  &quot;applicationStateChanged(Qt::ApplicationSuspended)&quot;
                  signal is sent! --&gt;
            &lt;meta-data android:name=&quot;android.app.background_running&quot; android:value=&quot;false&quot;/&gt;
            &lt;!-- Background running --&gt;
        &lt;/activity&gt;
        &lt;/application&gt;
        &lt;uses-sdk android:minSdkVersion=&quot;10&quot; android:targetSdkVersion=&quot;14&quot;/&gt;
        &lt;supports-screens android:largeScreens=&quot;true&quot; android:normalScreens=&quot;true&quot; android:anyDensity=&quot;true&quot; android:smallScreens=&quot;true&quot;/&gt;
        &lt;uses-feature android:name=&quot;android.hardware.nfc&quot; android:required=&quot;true&quot;/&gt;
        &lt;uses-permission android:name=&quot;android.permission.NFC&quot;/&gt;
    &lt;/manifest&gt;
    

  [1]: https://wiki.qt.io/New_Features_in_Qt_5.6
  [2]: http://wiki.qt.io/Qt5ForAndroidBuilding

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How to get NFC working on Android using Qt 5.6