Migrate to null-safety

.gitignore

@@ -11,3 +11,8 @@ pubspec.lock
 # Directory created by dartdoc
 # If you don't generate documentation locally you can remove this line.
 doc/api/
+
+qrcode/android/.project
+qrcode/example/android/.project
+.DS_Store
+qrcode/android/.idea

qrcode/android/.settings/org.eclipse.buildship.core.prefs

@@ -1,2 +1,13 @@
-connection.project.dir=../example/android
+arguments=
+auto.sync=false
+build.scans.enabled=false
+connection.gradle.distribution=GRADLE_DISTRIBUTION(VERSION(7.0-rc-1))
+connection.project.dir=
 eclipse.preferences.version=1
+gradle.user.home=
+java.home=/Library/Java/JavaVirtualMachines/jdk-12.0.1.jdk/Contents/Home
+jvm.arguments=
+offline.mode=false
+override.workspace.settings=true
+show.console.view=true
+show.executions.view=true

qrcode/android/build.gradle

@@ -2,14 +2,14 @@ group 'com.example.qrcode'
 version '1.0-SNAPSHOT'
 
 buildscript {
-    ext.kotlin_version = '1.3.10'
+    ext.kotlin_version = '1.5.21'
     repositories {
         google()
         jcenter()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.1'
+        classpath 'com.android.tools.build:gradle:7.0.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -27,13 +27,13 @@ apply plugin: 'kotlin-android-extensions'
 apply plugin: 'kotlin-kapt'
 
 android {
-    compileSdkVersion 28
+    compileSdkVersion 29
 
     sourceSets {
         main.java.srcDirs += 'src/main/kotlin'
     }
     defaultConfig {
-        minSdkVersion 16
+        minSdkVersion 21
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }
     lintOptions {
@@ -43,6 +43,7 @@ android {
 
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
-    implementation "com.journeyapps:zxing-android-embedded:4.1.0"
-    implementation "androidx.appcompat:appcompat:1.0.2"
+    implementation('com.journeyapps:zxing-android-embedded:4.2.0') { transitive = false }
+    implementation 'androidx.appcompat:appcompat:1.0.2'
+    implementation 'com.google.zxing:core:3.3.0'
 }

qrcode/android/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists