初次运行Android报错Connect to 127.0.0.1:7890 [/127.0.0.1] failed: Connection refused (Connection refused)

在下载好各种依赖及启动虚拟机后，运行android app, 在build过程中会报错 connect fail，log中会有错误信息例如：

“Could not resolve all files for configuration ':app:_internal_aapt2_binary'.”

“Connect to 127.0.0.1:7890 [/127.0.0.1] failed: Connection refused (Connection refused)”

查了一些文章，做了三处修改，不确定是哪个生效了，大家可以挨个试一下。

1. 修改build.gradle中的配置

初次创建工程时，build.gradle中默认为：

buildscript {
    repositories {
        google()
        jcenter()
      
    }
    dependencies {
        classpath "com.android.tools.build:gradle:4.1.2"

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

allprojects {
    repositories {
        google()
        jcenter()
    }
}

参考网上大家分享的修改，把jcenter()注释掉后增加了一些maven地址，如下

buildscript {
    repositories {
        google()
        //jcenter()
        maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
        maven { url 'https://maven.aliyun.com/repository/public/' }
        maven { url 'https://maven.aliyun.com/repository/google/' }
        maven { url 'https://maven.aliyun.com/repository/jcenter/' }
        maven { url 'https://maven.aliyun.com/repository/central/' }
    }
    dependencies {
        classpath "com.android.tools.build:gradle:4.1.2"

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

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

根据as的弹窗提示选择“sync now”，会重新下载很多包。

2. 关掉proxy setting

做完第一步之后build还是会报错，彻底关掉as之后，重新打开，在HTTP Proxy设置中将“Auto-dectect proxy settings" 切换为 “No proxy".

3. 注释掉自动生成的proxyhost和proxyport配置

 第三步做完就，BUILD SUCCESSFUL啦！