Update examples to fix a problem related to a breaking Flutter plugin…

…s (see: flutter/flutter#27226) and a breaking change to ImageStream listener API.

example/android/app/build.gradle

@@ -25,7 +25,7 @@ apply plugin: 'com.android.application'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 27
+    compileSdkVersion 28
 
     lintOptions {
         disable 'InvalidPackage'

example/android/gradle.properties

@@ -1 +1,2 @@
 org.gradle.jvmargs=-Xmx1536M
+android.enableR8=true

example/ios/Flutter/flutter_export_environment.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+# This is a generated file; do not edit or check into version control.
+export "FLUTTER_ROOT=C:\Users\chris\flutter"
+export "FLUTTER_APPLICATION_PATH=C:\Users\chris\Documents\matrix_gesture_detector\example"
+export "FLUTTER_TARGET=lib\main.dart"
+export "FLUTTER_BUILD_DIR=build"
+export "SYMROOT=${SOURCE_ROOT}/../build\ios"
+export "FLUTTER_FRAMEWORK_DIR=C:\Users\chris\flutter\bin\cache\artifacts\engine\ios"
+export "FLUTTER_BUILD_NAME=1.0.0"
+export "FLUTTER_BUILD_NUMBER=1"

example/lib/blur_demo.dart

@@ -59,8 +59,8 @@ class ImageData {
     ImageStream oldImageStream = imageStream;
     imageStream = imageProvider.resolve(createLocalImageConfiguration(context));
     if (imageStream.key != oldImageStream?.key) {
-      oldImageStream?.removeListener(imageLoaded);
-      imageStream.addListener(imageLoaded);
+      oldImageStream?.removeListener(ImageStreamListener(imageLoaded));
+      imageStream.addListener(ImageStreamListener(imageLoaded));
     }
   }