refactor: 重构项目 (#3)

example/android/app/build.gradle

@@ -1,8 +1,7 @@
 def localProperties = new Properties()
 def localPropertiesFile = rootProject.file('local.properties')
 if (localPropertiesFile.exists()) {
-    localPropertiesFile.withReader('UTF-8') { reader ->
-        localProperties.load(reader)
+    localPropertiesFile.withReader('UTF-8') { reader -> localProperties.load(reader)
     }
 }
 
@@ -26,16 +25,29 @@ apply plugin: 'kotlin-android'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion flutter.compileSdkVersion
+    ndkVersion flutter.ndkVersion
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
 
     sourceSets {
         main.java.srcDirs += 'src/main/kotlin'
     }
 
     defaultConfig {
+        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "dev.yanshouwang.bluetooth_low_energy_example"
+        // You can update the following values to match your application needs.
+        // For more information, see: https://docs.flutter.dev/deployment/android#reviewing-the-build-configuration.
         minSdkVersion 21
-        targetSdkVersion 30
+        targetSdkVersion flutter.targetSdkVersion
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
     }