how to get compileSdkVersion equal or higer than the options shown - android-studio

Question

I'm making an app with ads in it with AdMob: https://developers.google.com/admob/android/quick-start?hl=he.
In order to that I need a "compileSdkVersion 28 or higher", so when I tried to change it by doing:
right-click on "app" > open module settings > compile SDK version, I was shown that the maximum option is: compile SDK version 27, and not 28 the minimum requirements for Google AdMob
also here is my build.gradle(Module: app):
apply plugin: 'com.android.application'
android {
compileSdkVersion 26
defaultConfig {
applicationId "com.example.admin.minesweeperyannai"
minSdkVersion 21
targetSdkVersion 26
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:26.1.0'
implementation 'com.android.support.constraint:constraint-layout:1.1.3'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
implementation 'com.google.android.gms:play-services-ads:19.4.0'//Google AdMob dependency
}
Also, I checked on their website and found out that I cant use lower versions than 19.4.0 or 18.1.0 (I didn't understand which one is the minimum but both of them didn't work).
This is the error I get when I try to use one of those versions:
error: failed linking references.
And I know my code is good because I've tried using the version: "play-services-ads 17.1.1" and it worked but only with test ads and not real ads, so to sum up I would like to know how to get Compile Sdk Version 28 or higher in order to show ads on my app.

Answer 1

This menu showing you the versions that you already installed it
so to get version 28 or 29 you need to install it
The first option is to change it from build.gradle file for example
android
compileSdkVersion 29
defaultConfig {
.....
minSdkVersion 21
targetSdkVersion 29
}
....
}
Or from SDK Manager select show package details and install Android SDK Platform 28 or 29 then select it from the Compile Sdk Version menu