编译错误提示信息：

Suggestion: add 'tools:replace="android:networkSecurityConfig"' to <application> element at AndroidManifest.xml:16:5-199:19 to override.

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        android:networkSecurityConfig="@xml/network_security_config"
        tools:replace="android:networkSecurityConfig">

除了加这句以外，还应该加一句

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
 

否则会报错 The prefix "tools" for attribute "tools:replace" associated with an element type "application" is not bound.