Android Studio 3.0.1 Error: Gradle project sync failed. Basic functionality (e.g. editing, debugging) will not work properly

Question

I've installed Android studio 3.0.1 and tried to build very first app with choosing an empty activity, but I've get the message:

Gradle project sync failed. Basic functionality (e.g. editing, debugging) will not work properly

and error message like this:

Unable to resolve dependency for ':app@releaseUnitTest/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 parse POM https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.pom Already seen doctype.

and this is first part of log message is:

2018-01-03 11:11:12,671 [d thread 8] WARN - ect.sync.idea.ProjectSetUpTask - Already seen doctype. Consult IDE log for more details (Help | Show Log) 2018-01-03 11:11:12,671 [d thread 8] INFO - e.project.sync.GradleSyncState - Gradle sync failed: Already seen doctype.

I've tried some suggested solution like changing gradle version, update Kotlin plugin(!) and so, but they didn't work.

Any solution?

Answer 1

This problem occurs when the Build Tools Version is not set for the project. You just set the build tools version by following this process...

By opening your project structure [File->Project Structure] and selecting the Build Tools Version from app's property tab in Modules section.

This will add build tools version to your gradle file (Module:app) and re-sync the project.

Answer 2

The problem caused by my connection. I needed to set proxy to download some components.

Answer 3

The error happens under fluctuating network. So at first make sure your connection is stable. Plus, if you are using any VPN check your gradle.properties is configured correctly.

The correct form of VPN connection on gradle.properties is as follows,

systemProp.http.proxyHost=127.0.0.1
systemProp.http.proxyPort=8080
systemProp.https.proxyHost=127.0.0.1
systemProp.https.proxyPort=8080

My host connection is 127.0.0.1, and its port is 8080 for both http and https.

Just one more thing, make sure adding https (It is mandatory).

Answer 4

I had the same problem when i was upgrading to android studio 3.1.2 and the problem i was using the previous JDK which i installed before 5 years back.

The steps:-

Go to File -> Project Structures -> SDK Location -> JDK Location -> check the 
Option Use embedded JDK (recommended).

Answer 5

Suddenly My Project showing this Error(Gradle project sync failed. Basic functionality (e.g. editing, debugging) will not work properly). Then i Try to various solutions but not solved.
Then i close the android studio, and open the project location and delete the .idea and .iml file, After deleting this file open the project again on Android studio, after that the project working fine.

Answer 6

For me the issue was one of the external libraries required SDK 28 but android studio didnt have it so it did not work. I installed SDK 28 and the problem was fixed. I saw the problem in the log file it generated

Answer 7

I had the same problem, I did download gradle version and used it as a local distribution. Settings/Build,../Gradle/Use local distribution. Else you will have to reinstall all the software.

Answer 8

The solution is kinda of very simple. It's because the "compileSdkVersion" that you are using in your build.gradle (Module:app) is higher than the SDK installed in your Android studio. Now, what to do? Just go on SDK Manager and download an Api Level higher or equal to your "compileSdkVersion" and you're done

Answer 9

Look at the manifest, something may have to go wrong there. In my case I had this label <uses-sdk android: minSdkVersion = "7" android: targetSdkVersion = "15" />, which was from an example. Then the error is displayed, and the correspondent is now updated <uses-sdk android: minSdkVersion = "15" android: targetSdkVersion = "27" />

Answer 10

I tried all suggestions, only one works for me:

• open 'Gradle' tab on right vertical panel
• right click on project name
• 'Refresh Gradle Dependencies' and wait background downloading
• right click on project name again
• 'Reload Gradle Project' and wait refreshing

Answer 11

Gradle project sync failed. Basic functionality (e.g. editing, debugging) will not work properly

Go to gradle scripts -> build gradle(app) -> made following changes:

Finally it works.