copy license files to flutter assets during build

android/app/collect_licenses.gradle

@@ -2,7 +2,7 @@ import groovy.json.JsonOutput
 
 import java.util.regex.Pattern
 
-def collectLicenses(File ossPluginResDir, File outDir) {
+def collectLicenses(File rootDir, File ossPluginResDir, File outDir) {
 
     def pattern = Pattern.compile("^(\\d+:\\d+) (.*)\$")
 
@@ -21,11 +21,13 @@ def collectLicenses(File ossPluginResDir, File outDir) {
         throw new GradleException("Cannot find/read ${metadata.absolutePath}")
     }
 
-    if (!outDir.isDirectory() || !outDir.canExecute()) {
-        throw new GradleException("Insufficient permissions to ${outDir.absolutePath}")
+    if (!outDir.exists() || !outDir.canExecute()) {
+        if (!outDir.mkdir()) {
+            throw new GradleException("Failed to create ${outDir.absolutePath}")
+        }
     }
 
-    def outFile = new File(outDir, "android_licenses.json")
+    def outFile = new File(outDir, "android.json")
     if (outFile.exists()) {
         outFile.delete()
     }
@@ -35,10 +37,12 @@ def collectLicenses(File ossPluginResDir, File outDir) {
     var index = 0
     licenses.eachLine { line ->
         def indices = "$index:${line.length()}"
+        println line
         licenseMap[indices] = line
         index += line.length() + 1
     }
 
+    println "Modules:"
     def licenseList = []
     metadata.eachLine { line ->
         def matcher = pattern.matcher(line)
@@ -56,17 +60,32 @@ def collectLicenses(File ossPluginResDir, File outDir) {
     }
 
     // add zxing_licenses which are not detected
+    println "adding zxing licenses"
     licenseList.add(PackageName: "ZXing Core (3.3.0)", PackageLicense: "https://www.apache.org/licenses/LICENSE-2.0.txt")
     licenseList.add(PackageName: "ZXing Android Core (3.3.0)", PackageLicense: "https://www.apache.org/licenses/LICENSE-2.0.txt")
 
     outFile.write(new JsonOutput().toJson(licenseList))
     println "Created ${outFile.absolutePath}"
+
+    // copy license assets to flutter resources
+    def licensesDir = new File(rootDir, "licenses/");
+    copy {
+        from(licensesDir.absolutePath) {
+            include "**/*txt"
+            include "**/*json"
+        }
+        into outDir
+    }
+
+    // remove not needed oss-licenses-plugin files
+    licenses.delete()
+    metadata.delete()
 }
 
 task collectLicenses() {
     dependsOn(":app:releaseOssLicensesTask")
     doLast {
-        def inputDir = new File(project.buildDir, "generated/third_party_licenses/release/res/raw/")
-        collectLicenses(inputDir, new File(project.rootDir.parent, "assets/licenses/"))
+        def ossPluginResDir = new File(project.buildDir, "generated/third_party_licenses/release/res/raw/")
+        collectLicenses(project.rootDir, ossPluginResDir, new File(project.rootDir.parent, "assets/licenses/android/"))
     }
 }

assets/licenses/.gitignore

@@ -1,2 +1,2 @@
 helper.json
-android_licenses.json
+android/*

lib/android/init.dart

@@ -91,21 +91,29 @@ class DismissKeyboard extends StatelessWidget {
 }
 
 void _initLicenses() async {
+
+  const licenseDir = 'assets/licenses/android';
+
   final androidProjectsToLicenseUrl = await rootBundle.loadStructuredData<List>(
-    'assets/licenses/android_licenses.json',
+    '$licenseDir/android.json',
     (value) async => jsonDecode(value),
   );
 
   // mapping from url to license text
-  final urlToFile = await rootBundle.loadStructuredData<Map>(
-    'assets/licenses/license_indices.json',
-    (value) async => jsonDecode(value),
+  final fileMap = await rootBundle.loadStructuredData<Map>(
+    '$licenseDir/map.json',
+        (value) async => jsonDecode(value),
   );
 
   final urlToLicense = <String, String>{};
-  urlToFile.forEach((url, file) async {
-    final licenseText = await rootBundle.loadString('assets/licenses/$file');
-    urlToLicense[url] = licenseText;
+  fileMap.forEach((url, file) async {
+    String licenseText = url;
+    try {
+      licenseText = await rootBundle.loadString('$licenseDir/$file');
+      urlToLicense[url] = licenseText;
+    } catch (_) {
+      // failed to read license file, will use the url
+    }
   });
 
   if (androidProjectsToLicenseUrl.isNotEmpty) {

pubspec.yaml

@@ -91,6 +91,7 @@ flutter:
     - assets/product-images/
     - assets/graphics/
     - assets/licenses/
+    - assets/licenses/android/
 
   # An image asset can refer to one or more resolution-specific "variants", see
   # https://flutter.dev/assets-and-images/#resolution-aware.