相关疑难解决方法(0)

我尝试将recyclerview添加到我的项目并出现此错误,我从android studio依赖项添加它

升级到androidstudio 3.0后,gradle停止工作:

无法解析':app @ debug/compileClasspath'的依赖关系:无法解析com.android.support:appcompat-v7:26.1.0.

无法解析com.android.support:appcompat-v7:26.1.0.要求:项目:app

无法解析com.android.support:appcompat-v7:26.1.0.无法获取资源" https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.pom ".无法获取" https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.pom ".连接到dl.google.com:443 [dl.google.com/172.217.22.110]失败:连接超时:连接已连接超时:连接

我检查了代理,它的工作原理.

这是一个新项目,没有改变android studio向导生成的内容.

谢谢你的帮助.

我安装了最新版本的android studio。我有已经安装的jdk 8。当我打开android studio时，出现以下错误。

Unable to resolve dependency for ':app@debugUnitTest/compileClasspath': Could not resolve com.android.support:appcompat-v7:26.1.0.

Could not resolve com.android.support:appcompat-v7:26.1.0.
Required by:
    project :app
 > Could not resolve com.android.support:appcompat-v7:26.1.0.
    > Could not get resource 'https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.pom'.
          > Could not GET 'https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.pom'.
                   > sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
                               > PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
                                              > unable to find valid certification path to requested target  

因此，我删除了JDK …

我下载了Android Studio 3.0,并开始关注构建我的第一个应用教程.但Gradle抛出的错误如下:

无法解析com.android.support:appcompat-v7:26.1.0.

我搜索的SO像类似的问题,这个和那个,但没有人帮助我.

最终我发现我正在使用Android Studio的代理:

要解决这个错误,我必须通过将这些行添加到gradle.properties文件来实现Gradle的代理:

systemProp.http.proxyHost=127.0.0.1
systemProp.http.nonProxyHosts=localhost, 127.0.0.1
org.gradle.jvmargs=-Xmx1536m
systemProp.http.proxyPort=8118

systemProp.https.proxyHost=127.0.0.1
systemProp.https.nonProxyHosts=localhost, 127.0.0.1
systemProp.https.proxyPort=8118

添加上述语句后gradle.properties,错误得到解决.请注意,需要将两个 代理HTTP和HTTPS代理添加到Gradle属性

There are many different questions about this, but the problems there are about using v7.28.0, v7.28.+, v7.28.0.0-rc02 But when I sync my project I get this error:

Unable to resolve dependency for ':app@debug/compileClasspath': Could not resolve com.android.support:appcompat-v7:28.0.0.

I've checked Support library setup and followed it's instructions but it didn't help.

This is my module app

buildscript {
    repositories {
        maven { url 'https://plugins.gradle.org/m2/'}
    }
    dependencies {
        classpath 'gradle.plugin.com.onesignal:onesignal-gradle-plugin:0.12.1'
    }
}
apply plugin: 'com.onesignal.androidsdk.onesignal-gradle-plugin'

repositories {
    maven { url …