Android Studio : Could not download FastInfoset.jar (com.sun.xml.fastinfoset:FastInfoset:1.2.15): No cached version available for offline mode error

I am a new user of the android studio. Initially, I faced with problems like the run button being disabled, and the XML display showing nothing.

When I was trying to resolve these problems, I confront with a bunch of error codes.

A problem occurred configuring root project 'Myfirstapp'.
   > Could not resolve all artifacts for configuration ':classpath'.
   > Could not download protobuf-java.jar (com.google.protobuf:protobuf-java:3.4.0): No cached version available for offline mode
   > Could not download bcpkix-jdk15on.jar (org.bouncycastle:bcpkix-jdk15on:1.56): No cached version available for offline mode
   > Could not download bcprov-jdk15on.jar (org.bouncycastle:bcprov-jdk15on:1.56): No cached version available for offline mode
   > Could not download fastutil.jar (it.unimi.dsi:fastutil:7.2.0): No cached version available for offline mode
   > Could not download jimfs.jar (com.google.jimfs:jimfs:1.1): No cached version available for offline mode
   > Could not download guava.jar (com.google.guava:guava:27.1-jre): No cached version available for offline mode
   > Could not download httpclient.jar (org.apache.httpcomponents:httpclient:4.5.6): No cached version available for offline mode
   > Could not download httpcore.jar (org.apache.httpcomponents:httpcore:4.4.10): No cached version available for offline mode
   > Could not download kotlin-reflect.jar (org.jetbrains.kotlin:kotlin-reflect:1.3.71): No cached version available for offline mode
   > Could not download antlr4.jar (org.antlr:antlr4:4.5.3): No cached version available for offline mode
   > Could not download juniversalchardet.jar (com.googlecode.juniversalchardet:juniversalchardet:1.0.3): No cached version available for offline mode
   > Could not download gson.jar (com.google.code.gson:gson:2.8.5): No cached version available for offline mode
   > Could not download kotlin-stdlib.jar (org.jetbrains.kotlin:kotlin-stdlib:1.3.71): No cached version available for offline mode
   > Could not download proguard-base.jar (net.sf.proguard:proguard-base:6.0.3): No cached version available for offline mode
   > Could not download jdom2.jar (org.jdom:jdom2:2.0.6): No cached version available for offline mode
   > Could not download commons-compress.jar (org.apache.commons:commons-compress:1.12): No cached version available for offline mode
   > Could not download trove4j.jar (org.jetbrains.trove4j:trove4j:20160824): No cached version available for offline mode
   > Could not download commons-codec.jar (commons-codec:commons-codec:1.10): No cached version available for offline mode
   > Could not download jaxb-runtime.jar (org.glassfish.jaxb:jaxb-runtime:2.3.1): No cached version available for offline mode
   > Could not download FastInfoset.jar (com.sun.xml.fastinfoset:FastInfoset:1.2.15): No cached version available for offline mode

Here is a screenshot of errors i am facing:

Make sure you have a stable internet connection before try to sync your project. an check your proxy settings. Make sure the auto detect option is checked. you can access it in Files > Settings > Appearance and Behavior > System Settings > HTTP proxy for windows though. Am sure for linux its the same path.
and to enable and disable gradle offline mode,, its just easy on android 3.6 an the right pane in the image second right icon under gradle

Note on Gradle you are using "Gradle offline" that is why the cache is failing (6th button from the left).

If deactivated the "No cached version available for offline mode" errors would disappear.

You're currently using offline mode.

In order to use gradle's offline mode, it must've been connected to the internet at least once to download the required dependencies and cache the modules that are going to be used in your project.

The process to disable it is very simple:

1. Click on the word gradle in your right side of the screen.

2. A panel will appear with some information and tasks, from the top tools bar (The one below the word gradle in your picture) and to the very right, you'll see a button with settings (configuration) icon, to its left, there's a highlighted button with crossed-line icon, click on it to enable online mode.

3. You'll need to sync your project (You will need to have access to the internet), by going to Files -> Sync Project with gradle files

4. Then Run -> Rebuild, to build the project and have the preview in your designer.

5. After the sync finishes, you can repeat the first step to toggle offline mode if you wish to, your project will have cached the modules you need and you'll be able to build your project without internet.

> Source: https://developer.android.com/studio/releases#3.6-gradle-offline-ui
>
Search for: New location to toggle Gradle's offline mode
>
> More about Offline-Mode: https://developer.android.com/studio/build/optimize-your-build#offline_mode
>
> Search for: Enable offline mode

#Happy coding!