1 Post请求失败

• 异常
  W/System.err: java.net.SocketException: socket failed: EACCES (Permission denied)

• 原因
  权限不够
  在文件清单中添加uses-permission

• 方案

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher">
        <activity android:name=".MainActivity">
        </activity>
    </application>
    <uses-permission android:name="android.permission.INTERNET"/>
</manifest>

2 Gradle下载失败

• 场景
  首次使用Android Studio新建Andorid项目,Gradle下载相关组件时过慢或失败
• 方案
  添加下载源,修改第一层文件夹下的build.gradle文件,添加maven{url ‘http://maven.aliyun.com/nexus/content/groups/public/’},完整问文件如下:

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        maven{url 'http://maven.aliyun.com/nexus/content/groups/public/'}
        google()
        jcenter()
    }
    dependencies {
        classpath "com.android.tools.build:gradle:4.0.1"

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        maven{url 'http://maven.aliyun.com/nexus/content/groups/public/'}
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

本文地址：https://blog.csdn.net/Xin_101/article/details/100661674