system proxy & build_windows script

android/app/src/main/kotlin/com/github/wgh136/pixes/MainActivity.kt

@@ -1,5 +1,29 @@
 package com.github.wgh136.pixes
 
 import io.flutter.embedding.android.FlutterActivity
+import io.flutter.plugins.GeneratedPluginRegistrant
+import io.flutter.plugin.common.MethodChannel
+import io.flutter.embedding.engine.FlutterEngine
 
-class MainActivity: FlutterActivity()
+class MainActivity: FlutterActivity() {
+    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
+        GeneratedPluginRegistrant.registerWith(flutterEngine)
+        //获取http代理
+        MethodChannel(
+            flutterEngine.dartExecutor.binaryMessenger,
+            "pixes/proxy"
+        ).setMethodCallHandler { _, res ->
+            res.success(getProxy())
+        }
+    }
+
+    private fun getProxy(): String{
+        val host = System.getProperty("http.proxyHost")
+        val port = System.getProperty("http.proxyPort")
+        return if(host!=null&&port!=null){
+            "$host:$port"
+        }else{
+            "No Proxy"
+        }
+    }
+}