Android target: not installed in Ubuntu

Question

I want to install Android SDK and Cordova if run this

$cordova requirements

I have the same problem

Requirements check results for android:
Java JDK: installed 
Android SDK: installed true
Android target: not installed 
android: Command failed with exit code 1 Error output:
Exception in thread "main" java.lang.UnsupportedClassVersionError: com/android/sdklib/tool/AvdManagerCli : Unsupported major.minor version 52.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:803)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:442)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:64)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:354)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:348)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:347)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:312)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
Gradle: not installed 
Could not find an installed version of Gradle either in Android Studio,
or on your system to install the gradle wrapper. Please include gradle 
in your path, or install Android Studio
Error: Some of requirements check failed

I searched for the Error but I can't find a good solution and most answers are for Windows or mac but not for Linux

sdk = /home/myland/Documents/tools
platform-tools = /home/myland/Documents/tools/platform-tools

what can I do about the problem?

Answer 1

i update java to version 8 and install Gradle and make AVD android now good

# cordova requirements
Requirements check results for android:
Java JDK: installed 1.8.0
Android SDK: installed true
Android target: installed android-26,android-25
Gradle: installed /usr/share/gradle/bin/gradle 

Answer 2

if any body get the error in linux can do the step one download last Android stdio , JDK lasts and NodeJs with install cordova

npm install -g cordova --save 

step two

export ANDROID_HOME=/home/user/Android/Sdk
export PATH=${PATH}:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools
/home/user/android-studio/gradle/gradle-4.1/bin/gradle

if install download in folder home thank you