first bits of the nfc reader

app/src/main/AndroidManifest.xml

@@ -2,6 +2,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           package="org.mosad.seil0.projectlaogai">
     <uses-permission android:name="android.permission.INTERNET"/>
+    <uses-permission android:name="android.permission.NFC" />
 
     <application
             android:allowBackup="true"
@@ -17,6 +18,7 @@
                 android:label="@string/app_name"
                 android:theme="@style/SplashTheme"
                 android:screenOrientation="portrait">
+
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>
                 <category android:name="android.intent.category.LAUNCHER"/>
@@ -27,7 +29,17 @@
                 android:name=".MainActivity"
                 android:label="@string/app_name"
                 android:theme="@style/AppTheme.Light"
-                android:screenOrientation="portrait">
+                android:screenOrientation="portrait"
+                android:launchMode="singleTop">
+
+            <!-- nfc stuff -->
+            <intent-filter>
+                <action android:name="android.nfc.action.TECH_DISCOVERED"/>
+            </intent-filter>
+
+            <meta-data android:name="android.nfc.action.TECH_DISCOVERED"
+                       android:resource="@xml/nfc_tech_filter" />
+
         </activity>
     </application>
 

app/src/main/java/org/mosad/seil0/projectlaogai/MainActivity.kt

@@ -23,6 +23,8 @@
 package org.mosad.seil0.projectlaogai
 
 import android.graphics.Color
+import android.nfc.NfcAdapter
+import android.nfc.Tag
 import android.os.Bundle
 import android.view.Menu
 import android.view.MenuItem
@@ -32,6 +34,7 @@ import androidx.core.view.GravityCompat
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.FragmentTransaction
 import com.afollestad.aesthetic.Aesthetic
+import com.afollestad.materialdialogs.MaterialDialog
 import com.google.android.material.navigation.NavigationView
 import kotlinx.android.synthetic.main.activity_main.*
 import kotlinx.android.synthetic.main.app_bar_main.*
@@ -42,6 +45,7 @@ import org.mosad.seil0.projectlaogai.controller.PreferencesController.Companion.
 import org.mosad.seil0.projectlaogai.fragments.*
 import kotlin.system.measureTimeMillis
 
+// TODO save the current fragment to show it when the app is restarted
 class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
 
     private var activeFragment: Fragment = HomeFragment() // the currently active fragment, home at the start
@@ -68,6 +72,16 @@ class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelecte
         toggle.syncState()
 
         nav_view.setNavigationItemSelectedListener(this)
+
+        // TODO nfc stuff, needs to move to it's own function
+        if (intent.action == NfcAdapter.ACTION_TECH_DISCOVERED) {
+
+            val tag: Tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG)
+            MaterialDialog(this)
+                .title(text = "nfc tag detected")
+                .message(text = tag.toString())
+                .show()
+        }
     }
 
     override fun onResume() {

app/src/main/java/org/mosad/seil0/projectlaogai/fragments/MensaFragment.kt

@@ -43,7 +43,6 @@ import org.mosad.seil0.projectlaogai.uicomponents.MealLinearLayout
 /**
  * The mensa controller class
  * contains all needed parts to display and the mensa detail screen
- * TODO investigate reading the mensa card value via nfc in a background task, show value if card detected
  */
 class MensaFragment : Fragment() {
 

app/src/main/res/layout/fragment_timetable.xml

@@ -27,6 +27,6 @@
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:clickable="true" android:id="@+id/faBtnAddLesson" android:elevation="7dp"
-            android:visibility="visible" android:layout_gravity="bottom|center|end" android:layout_marginEnd="11dp"
+            android:visibility="gone" android:layout_gravity="bottom|center|end" android:layout_marginEnd="11dp"
             android:layout_marginBottom="11dp" android:focusable="true"/>
 </FrameLayout>

app/src/main/res/xml/nfc_tech_filter.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
+    <tech-list>
+        <tech>android.nfc.tech.NfcA</tech>
+    </tech-list>
+</resources>