Use Android broadcast ACTION_ADAPTER_STATE_CHANGED

To avoid polling of the NFC adapter state
a signal is added to the QNearFieldManager.

Change-Id: If9e1e8025cca2deb1338fa7db255ebe171cab823
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

2 files changed, 74 insertions, 1 deletions

diff --git a/src/android/nfc/nfc.pro b/src/android/nfc/nfc.pro
index 89026b75..a725fb7d 100644
--- a/src/android/nfc/nfc.pro
+++ b/src/android/nfc/nfc.pro
@@ -7,7 +7,8 @@ PATHPREFIX = $$PWD/src/org/qtproject/qt5/android/nfc
 
 JAVACLASSPATH += $$PWD/src/
 JAVASOURCES += \
-    $$PWD/src/org/qtproject/qt5/android/nfc/QtNfc.java
+    $$PWD/src/org/qtproject/qt5/android/nfc/QtNfc.java \
+    $$PWD/src/org/qtproject/qt5/android/nfc/QtNfcBroadcastReceiver.java \
 
 # install
 target.path = $$[QT_INSTALL_PREFIX]/jar
diff --git a/src/android/nfc/src/org/qtproject/qt5/android/nfc/QtNfcBroadcastReceiver.java b/src/android/nfc/src/org/qtproject/qt5/android/nfc/QtNfcBroadcastReceiver.java
new file mode 100644
index 00000000..ea650ede
--- /dev/null
+++ b/src/android/nfc/src/org/qtproject/qt5/android/nfc/QtNfcBroadcastReceiver.java
@@ -0,0 +1,72 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 Governikus GmbH & Co. KG
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtNfc module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+package org.qtproject.qt5.android.nfc;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.nfc.NfcAdapter;
+
+
+public class QtNfcBroadcastReceiver extends BroadcastReceiver
+{
+    private Context qtContext;
+
+    public QtNfcBroadcastReceiver(Context context)
+    {
+        qtContext = context;
+        IntentFilter filter = new IntentFilter(NfcAdapter.ACTION_ADAPTER_STATE_CHANGED);
+        qtContext.registerReceiver(this, filter);
+    }
+
+    public void unregisterReceiver()
+    {
+        qtContext.unregisterReceiver(this);
+    }
+
+    public void onReceive(Context context, Intent intent)
+    {
+        final int state = intent.getIntExtra(NfcAdapter.EXTRA_ADAPTER_STATE, NfcAdapter.STATE_OFF);
+        jniOnReceive(state);
+    }
+
+    public native void jniOnReceive(int state);
+}