Add custom read/write helpers for MIFARE Classic tags

.github/workflows/example-app.yml

@@ -17,8 +17,8 @@ jobs:
         variant: [debug, release]
 
     steps:
-    - uses: actions/checkout@v4
-    - uses: actions/setup-java@v4
+    - uses: actions/checkout@v5
+    - uses: actions/setup-java@v5
       with:
         distribution: 'temurin'
         java-version: '21'
@@ -49,7 +49,7 @@ jobs:
         variant: [debug, release]
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
     - uses: subosito/flutter-action@v2
       with:
         channel: 'stable'

CHANGELOG.md

@@ -177,9 +177,7 @@
   * allow authentication of sector 0 (#157)
   * fix data type check in `writeBlock` (#161)
 
-## 3.6.0-rc.6
-
-This is a release candidate for 3.6.0. Please test it and report any issues.
+## 3.6.0
 
 * Requires Dart 3.6+ and Flutter 3.24+
 * Remove annoying dependency on `js` library, replace with `dart:js_interop`

android/gradle.properties

@@ -1,4 +1,4 @@
-org.gradle.jvmargs=-Xmx1536M
+org.gradle.jvmargs=-Xmx4096M
 android.enableJetifier=true
-AGPVersion=8.7.3
-KotlinVersion=2.1.0
+AGPVersion=8.13.0
+KotlinVersion=2.2.10

android/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 #Fri Sep 08 22:01:14 CST 2023
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.0.0-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

android/src/main/kotlin/im/nfc/flutter_nfc_kit/FlutterNfcKitPlugin.kt

@@ -89,7 +89,13 @@ class FlutterNfcKitPlugin : FlutterPlugin, MethodCallHandler, ActivityAware {
                     }
                 }
             }
-            if (!nfcHandler.post(handledFn)) {
+            val looperThread = nfcHandler.looper?.thread
+            if (looperThread == null || !looperThread.isAlive) {
+                val thread = HandlerThread("FlutterNfcKit").apply { start() }
+                nfcHandler = Handler(thread.looper)
+            }
+            val posted = nfcHandler.post(handledFn)
+            if (!posted) {
                 result.error("500", "Failed to post job to NFC Handler thread.", null)
             }
         }

example/android/gradle.properties

@@ -1,10 +1,10 @@
-org.gradle.jvmargs=-Xmx1536M
+org.gradle.jvmargs=-Xmx4096M
 
 android.useAndroidX=true
 android.enableJetifier=true
 android.defaults.buildfeatures.buildconfig=true
 android.nonTransitiveRClass=false
 android.nonFinalResIds=false
 
-AGPVersion=8.7.3
-KotlinVersion=2.1.0
+AGPVersion=8.13.0
+KotlinVersion=2.2.10

example/android/gradle/wrapper/gradle-wrapper.properties

@@ -2,4 +2,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStorePath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.11-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.0.0-bin.zip

example/pubspec.lock

@@ -92,7 +92,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "3.6.0-rc.6"
+    version: "3.6.0"
   flutter_test:
     dependency: "direct dev"
     description: flutter

lib/flutter_nfc_kit.dart

@@ -523,4 +523,138 @@ class FlutterNfcKit {
   static Future<Uint8List> readSector(int index) async {
     return await _channel.invokeMethod('readSector', {'index': index});
   }
+
+  /// Read a custom number of bytes from a MIFARE Classic tag (Android only).
+  ///
+  /// Requires a valid NFC session and a MIFARE Classic tag.
+  ///
+  /// Authentication is performed on each sector before reading.
+  /// Reading starts from [startSector] and [startBlockInSector], and continues
+  /// until [numBytes] are read.
+  ///
+  /// Note: Trailer blocks (last block of each sector) are skipped for safety,
+  /// as they contain key and access bits.
+  ///
+  /// Throws an [Exception] if the tag is not MIFARE Classic or if authentication fails.
+  ///
+  /// Returns a [List<int>] of the requested bytes (up to [numBytes]).
+  Future<List<int>> readDataFromTag({
+    required NFCTag tag,
+    int startSector = 1,
+    int startBlockInSector = 1,
+    int numBytes = 36,
+    String keyA = 'FFFFFFFFFFFF',
+    String? keyB,
+  }) async {
+    if (tag.type != NFCTagType.mifare_classic) {
+      throw Exception(
+          'Only MIFARE Classic tags are supported for this operation.');
+    }
+
+    final List<int> result = [];
+    final int neededBlocks = (numBytes / 16).ceil();
+    int blocksRead = 0;
+
+    for (int currentSector = startSector;
+        currentSector < tag.mifareInfo!.sectorCount!;
+        currentSector++) {
+      if (blocksRead >= neededBlocks) {
+        break;
+      }
+
+      final bool authOk = await FlutterNfcKit.authenticateSector(currentSector,
+          keyA: keyA, keyB: keyB);
+      if (!authOk) {
+        throw Exception('Authentication failed for $currentSector sector.');
+      }
+
+      int blockStart = (currentSector == startSector) ? startBlockInSector : 0;
+      int blocksInSector = (currentSector < 32) ? 4 : 16;
+
+      for (int blockOffset = blockStart;
+          blockOffset < blocksInSector - 1;
+          blockOffset++) {
+        if (blocksRead >= neededBlocks) break;
+
+        final int blockIndex = (currentSector < 32)
+            ? currentSector * 4 + blockOffset
+            : 32 * 4 + (currentSector - 32) * 16 + blockOffset;
+
+        final Uint8List block = await FlutterNfcKit.readBlock(blockIndex);
+        result.addAll(block);
+        blocksRead++;
+      }
+    }
+
+    return result.take(numBytes).toList();
+  }
+
+  /// Write a list of bytes to a MIFARE Classic tag (Android only).
+  ///
+  /// Requires a valid NFC session and a MIFARE Classic tag.
+  ///
+  /// Authentication is performed on each sector before writing.
+  /// Writing starts from [startSector] and [startBlockInSector], and continues
+  /// until all bytes in [data] are written.
+  ///
+  /// Note: Trailer blocks (last block of each sector) are skipped to prevent
+  /// overwriting sector keys and access conditions.
+  ///
+  /// Each block is 16 bytes. If a block is partially filled, it is padded with zeros.
+  ///
+  /// Throws an [Exception] if the tag is not MIFARE Classic or if authentication fails.
+  Future<void> writeDataToTag({
+    required NFCTag tag,
+    required List<int> data,
+    int startSector = 1,
+    int startBlockInSector = 1,
+    String keyA = 'FFFFFFFFFFFF',
+    String? keyB,
+  }) async {
+    if (tag.type != NFCTagType.mifare_classic) {
+      throw Exception(
+          'Only MIFARE Classic tags are supported for this operation.');
+    }
+
+    final int neededBlocks = (data.length / 16).ceil();
+    int blocksWritten = 0;
+
+    for (int currentSector = startSector;
+        currentSector < tag.mifareInfo!.sectorCount!;
+        currentSector++) {
+      if (blocksWritten >= neededBlocks) {
+        break;
+      }
+
+      final bool authOk = await FlutterNfcKit.authenticateSector(currentSector,
+          keyA: keyA, keyB: keyB);
+      if (!authOk) {
+        throw Exception('Authentication failed for $currentSector sector.');
+      }
+
+      int blockStart = (currentSector == startSector) ? startBlockInSector : 0;
+      int blocksInSector = (currentSector < 32) ? 4 : 16;
+
+      for (int blockOffset = blockStart;
+          blockOffset < blocksInSector - 1;
+          blockOffset++) {
+        if (blocksWritten >= neededBlocks) {
+          break;
+        }
+
+        final int blockIndex = (currentSector < 32)
+            ? currentSector * 4 + blockOffset
+            : 32 * 4 + (currentSector - 32) * 16 + blockOffset;
+
+        final List<int> blockData = List.filled(16, 0);
+        for (int i = 0; i < 16 && (blocksWritten * 16 + i) < data.length; i++) {
+          blockData[i] = data[blocksWritten * 16 + i];
+        }
+
+        await FlutterNfcKit.writeBlock(
+            blockIndex, Uint8List.fromList(blockData));
+        blocksWritten++;
+      }
+    }
+  }
 }

pubspec.yaml

@@ -1,6 +1,6 @@
 name: flutter_nfc_kit
 description: Provide NFC functionality on Android, iOS & Web, including reading metadata, read & write NDEF records, and transceive layer 3 & 4 data with NFC tags / cards
-version: 3.6.0-rc.6
+version: 3.6.0
 homepage: "https://github.com/nfcim/flutter_nfc_kit"
 
 environment: