Android同步项目时报 Gradle sync failed: Could not HEAD ... Received status code 400 from server: Bad Reque

解决方案如下：

进入到gradle缓存目录C:\Users\用户名\.gradle，找到gradle.properties文件，发现开了代理，注释掉即可

## For more details on how to configure your build environment visit
# http://www.gradle.org/docs/current/userguide/build_environment.html
#
# Specifies the JVM arguments used for the daemon process.
# The setting is particularly useful for tweaking memory settings.
# Default value: -Xmx1024m -XX:MaxPermSize=256m
# org.gradle.jvmargs=-Xmx2048m -XX:MaxPermSize=512m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8
#
# When configured, Gradle will run in incubating parallel mode.
# This option should only be used with decoupled projects. More details, visit
# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
# org.gradle.parallel=true
#Sat Aug 15 11:26:18 CST 2020
#systemProp.https.proxyPort=80
#systemProp.http.proxyHost=mirrors.neusoft.edu.cn
#systemProp.https.proxyHost=mirrors.neusoft.edu.cn
#systemProp.http.proxyPort=80