From 093516fbc295ffd5ebc103f249a5696f89c6d281 Mon Sep 17 00:00:00 2001
From: Mykhailo Nester <nsmisha.dev@gmail.com>
Date: Fri, 15 Oct 2021 12:14:00 +0300
Subject: [PATCH] - add NFC switch on UI to enable/disable nfc reader; (#232)

---
 app/src/main/AndroidManifest.xml              |  7 +---
 .../dgca/verifier/app/android/MainActivity.kt | 29 ++++++++++++++++
 .../app/android/reader/CodeReaderFragment.kt  | 34 ++++++++++++++++++-
 .../main/res/layout/fragment_code_reader.xml  | 26 ++++++++++++++
 app/src/main/res/values/strings.xml           |  2 ++
 5 files changed, 91 insertions(+), 7 deletions(-)

diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 4bfc4ac6..93943fa0 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -7,6 +7,7 @@
 
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.CAMERA" />
+    <uses-permission android:name="android.permission.NFC" />
 
     <application
         android:name=".DgcaApplication"
@@ -26,12 +27,6 @@
 
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
-
-            <intent-filter>
-                <action android:name="android.nfc.action.NDEF_DISCOVERED" />
-                <category android:name="android.intent.category.DEFAULT" />
-                <data android:mimeType="text/plain" />
-            </intent-filter>
         </activity>
 
         <activity
diff --git a/app/src/main/java/dgca/verifier/app/android/MainActivity.kt b/app/src/main/java/dgca/verifier/app/android/MainActivity.kt
index e3efa1af..72c79fb7 100644
--- a/app/src/main/java/dgca/verifier/app/android/MainActivity.kt
+++ b/app/src/main/java/dgca/verifier/app/android/MainActivity.kt
@@ -22,9 +22,12 @@
 
 package dgca.verifier.app.android
 
+import android.app.PendingIntent
+import android.content.Context
 import android.content.Intent
 import android.nfc.NdefMessage
 import android.nfc.NfcAdapter
+import android.nfc.NfcManager
 import android.os.Bundle
 import android.view.WindowManager
 import androidx.appcompat.app.AppCompatActivity
@@ -39,6 +42,7 @@ import timber.log.Timber
 @AndroidEntryPoint
 class MainActivity : AppCompatActivity() {
 
+    private var adapter: NfcAdapter? = null
     private lateinit var navHostFragment: NavHostFragment
     private lateinit var navController: NavController
 
@@ -69,6 +73,31 @@ class MainActivity : AppCompatActivity() {
         window.setBackgroundDrawable(ContextCompat.getDrawable(this, R.color.white))
     }
 
+    fun enableNfcForegroundDispatch() {
+        if (adapter == null) {
+            val nfcManager = getSystemService(Context.NFC_SERVICE) as NfcManager
+            adapter = nfcManager.defaultAdapter
+        }
+
+        try {
+            val intent = Intent(this, javaClass).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP)
+            val nfcPendingIntent = PendingIntent.getActivity(this, 0, intent, 0)
+            adapter?.enableForegroundDispatch(this, nfcPendingIntent, null, null)
+
+        } catch (ex: IllegalStateException) {
+            Timber.e(ex, "Error enabling NFC foreground dispatch")
+        }
+    }
+
+
+    fun disableNfcForegroundDispatch() {
+        try {
+            adapter?.disableForegroundDispatch(this)
+        } catch (ex: IllegalStateException) {
+            Timber.e(ex, "Error disabling NFC foreground dispatch")
+        }
+    }
+
     private fun checkNdefMessage(intent: Intent) {
         if (NfcAdapter.ACTION_NDEF_DISCOVERED == intent.action) {
             intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES)?.also { rawMessages ->
diff --git a/app/src/main/java/dgca/verifier/app/android/reader/CodeReaderFragment.kt b/app/src/main/java/dgca/verifier/app/android/reader/CodeReaderFragment.kt
index 061878f6..03b3e45e 100644
--- a/app/src/main/java/dgca/verifier/app/android/reader/CodeReaderFragment.kt
+++ b/app/src/main/java/dgca/verifier/app/android/reader/CodeReaderFragment.kt
@@ -160,18 +160,33 @@ class CodeReaderFragment : BindingFragment<FragmentCodeReaderBinding>(), NavCont
                 binding.countrySelector.setSelection(position)
             }
         }
+
+        binding.nfcSwitch.setOnCheckedChangeListener { _, isChecked ->
+            if (isChecked) {
+                enableNFC()
+            } else {
+                enableCamera()
+            }
+        }
     }
 
     override fun onResume() {
         super.onResume()
         findNavController().addOnDestinationChangedListener(this)
         lastText = ""
+
+        if (binding.nfcSwitch.isChecked) {
+            enableNFC()
+        } else {
+            enableCamera()
+        }
     }
 
     override fun onPause() {
         super.onPause()
         findNavController().removeOnDestinationChangedListener(this)
         binding.barcodeScanner.pause()
+        (requireActivity() as MainActivity).disableNfcForegroundDispatch()
     }
 
     override fun onDestinationChanged(
@@ -180,11 +195,28 @@ class CodeReaderFragment : BindingFragment<FragmentCodeReaderBinding>(), NavCont
         arguments: Bundle?
     ) {
         if (destination.id == R.id.codeReaderFragment) {
-            binding.barcodeScanner.resume()
+            if (binding.nfcSwitch.isChecked) {
+                enableNFC()
+            } else {
+                enableCamera()
+            }
+
             lastText = ""
         }
     }
 
+    private fun enableNFC() {
+        binding.barcodeScanner.pause()
+        binding.nfcOverlay.isVisible = true
+        (requireActivity() as MainActivity).enableNfcForegroundDispatch()
+    }
+
+    private fun enableCamera() {
+        binding.barcodeScanner.resume()
+        binding.nfcOverlay.isVisible = false
+        (requireActivity() as MainActivity).disableNfcForegroundDispatch()
+    }
+
     private fun showVerificationResult(
         standardizedVerificationResult: StandardizedVerificationResult,
         certificateModel: CertificateModel?,
diff --git a/app/src/main/res/layout/fragment_code_reader.xml b/app/src/main/res/layout/fragment_code_reader.xml
index a685a874..2d3927ca 100644
--- a/app/src/main/res/layout/fragment_code_reader.xml
+++ b/app/src/main/res/layout/fragment_code_reader.xml
@@ -22,6 +22,7 @@
 
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
@@ -47,6 +48,17 @@
         app:layout_constraintTop_toTopOf="parent"
         app:layout_constraintWidth_percent="0.85" />
 
+    <TextView
+        android:id="@+id/nfc_overlay"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:background="@color/black"
+        android:gravity="center"
+        android:text="@string/nfc_enabled"
+        android:textSize="@dimen/text_size_medium"
+        android:visibility="gone"
+        tools:visibility="visible" />
+
     <androidx.appcompat.widget.AppCompatImageButton
         android:id="@+id/settings"
         android:layout_width="48dp"
@@ -58,6 +70,19 @@
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
+    <com.google.android.material.switchmaterial.SwitchMaterial
+        android:id="@+id/nfc_switch"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="10dp"
+        android:checked="false"
+        android:paddingHorizontal="@dimen/default_margin"
+        android:text="@string/nfc_scan"
+        android:textColor="@color/grey_50"
+        android:textSize="@dimen/text_size_medium"
+        android:theme="@style/TextAppearance.Dgca.Switch"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/settings" />
 
     <TextView
         android:id="@+id/validate_with"
@@ -80,4 +105,5 @@
         app:layout_constraintBottom_toBottomOf="@id/validate_with"
         app:layout_constraintStart_toEndOf="@id/validate_with"
         app:layout_constraintTop_toTopOf="@id/validate_with" />
+
 </androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 0f6ab954..0b49c906 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -119,4 +119,6 @@
     <string name="certificate_valid_from_title">Certificate valid from</string>
     <string name="certificate_valid_until_title">Certificate valid until</string>
     <string name="personal_data_title">Personal data:</string>
+    <string name="nfc_enabled">NFC enabled</string>
+    <string name="nfc_scan">NFC scan</string>
 </resources>