如果你嘗試使用 http 連結 OkHttp3 就拋出異常: CLEARTEXT communication to " + host + " not permitted by network security policy

開發過程中由於 https ssl 需要購買證書，費用較高，通常測試環境我們仍然使用 http 下面方法是開啟 http 模式，

創建檔案 res/xml/network_security_config.xml 內容如下

		
neo@MacBook-Pro ~/AndroidStudioProjects/okhttp % cat app/src/main/res/xml/network_security_config.xml 
<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <domain-config cleartextTrafficPermitted="true">
        <domain includeSubdomains="true">localhost</domain>
    </domain-config>
</network-security-config>		
		
		

再 app/src/main/AndroidManifest.xml 檔案中增加 android:networkSecurityConfig="@xml/network_security_config"

		
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="cn.netkiller.okhttp">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:networkSecurityConfig="@xml/network_security_config">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

    <uses-permission android:name="android.permission.INTERNET" />
</manifest>