[SOLVED] UnityWebRequest Unknown Error - Android 9(API 레벨 28+)

안드로이드 API 9에서 webrequest http post 통신시 에러발생 (unknown error)

https://forum.unity.com/threads/android-9-cleartext-http-traffic-to-my_ip-not

permitted.594298/

https://developer.android.com/guide/topics/manifest/application-element

Android OS 9 Pie 버전부터는 WebView에 일반적인 텍스트로 "http://" URL 접근이 막혔음.

(tagetSdkVersion 28 이상일 경우)

참고 : https://developer.android.com/training/articles/security-config#CleartextTrafficPermitted

[해결방법]

https://stackoverflow.com/questions/45940861/android-8-cleartext-http-traffic-not-permitted

방법1. AndroidManifest.xml 에서 application 의 usesClearTextTraffic 속성 수정

<?xml version="1.0" encoding="utf-8"?>

<manifest ...>

    ...

    <application

        ...

        android:usesCleartextTraffic="true"

https://nobase-dev.tistory.com/category/Android%EA%B0%9C%EB%B0%9C/Tips

<?xml version="1.0" encoding="utf-8"?>
<!-- This file was automatically generated by the Google Play Games plugin for Unity
     Do not edit. -->
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.google.example.games.mainlibproj"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-sdk android:minSdkVersion="14" />
     
    <application android:usesCleartextTraffic="true">
        
        <!-- The space in these forces it to be interpreted as a string vs. int -->
        <meta-data android:name="com.google.android.gms.games.APP_ID"
            android:value="\u003319835351291" />
        <!-- Keep track of which plugin is being used -->
        <meta-data android:name="com.google.android.gms.games.unityVersion"
            android:value="\u0030.9.57" />
        <activity android:name="com.google.games.bridge.NativeBridgeActivity"
            android:theme="@android:style/Theme.Translucent.NoTitleBar.Fullscreen" />
    </application>
</manifest>