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Could not find method compileSdk() for arguments [30] on extension 'android' of type com.android.build.gradle.internal.dsl.BaseAppModuleExtension

I got the above error compileSdk() not found. While creating the app I have installed TargetSdk 31 and min SDK 19 But Apk does not install on Oreo Version so I have changed TargetSdk 31 to 31 and minSdk 19 to 16. I have uninstalled SDK 31 but it partially uninstalls. Please help me to solve this problem I am new to Android.

I have been strugling with this issue for hours until I looked at some older project. For some reason, newer versions of Android Studio mess up the directives from the Gradle file.
Just add "Version" after the name and it will work. So where you see "compileSdk" just rename it to "compileSdkVersion". You will probably also have to do that in "targetSdk" and so on.

in your <android_proj>/app/build.grandle instead of targetSdk 30 use:
android {
...
defaultConfig {
...
targetSdkVersion 30
}
}

How to get "CompileSdkversion" programmatically in Android

I have an About box in my App that displays information about the App, the phone and the data it uses. It's very useful when a user has a problem. I can get the phone's SDK version using "android.os.Build.VERSION.SDK_INT". However, I haven't found a way to get the value of "CompileSdkversion" which indicates the SDK version the App was compiled with. This is the value that is set in the build.gradle file.

While the Android OS version varies by user, the compileSdkVersion does not. For version X.Y.Z of your app, the compileSdkVersion is whatever you said it was when you compiled that app version. So long as your about box contains the app version, you know what compileSdkVersion that you used, if you keep track of that (e.g., check what it was in your version control system).
But, if you really want to have it be available to you at runtime, you have two options.
If your minSdkVersion is 31 or higher, you can use compileSdkVersion on ApplicationInfo. However, most likely, if you are reading this before the year 2026, your minSdkVersion is lower than that.
For older devices than Android 12, you could add a BuildConfig field for it, at least with newer versions of the Android Gradle Plugin:
android {
compileSdk 31
defaultConfig {
applicationId "com.commonsware.android.myapplication"
minSdk 23
targetSdk 31
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
buildConfigField "int", "COMPILE_SDK_VERSION", "$compileSdk"
}
// other stuff goes here
}
This takes your defined value for compileSdk and hoists it into BuildConfig.COMPILE_SDK_VERSION, so you can reference it at runtime. This was tested using a scrap Arctic Fox project, using Gradle 7.0.2 and 7.0.3 of the Android Gradle Plugin.

Here is the relationship between the three values:
minSdkVersion (lowest possible) <=
targetSdkVersion == compileSdkVersion (latest SDK)
CompileSdkVersion has nothing to do with what devices can and cannot run your app. Usually, you set this to be the latest version of the Android SDK.
And the targetSdkVersion should be fully tested and less or equal to compileSdkVersion.(It depends on your app)
If you are using the features of API level of 26 then you need to use compileSdkVersion 26, the lower version will give you an error.
Android supports backward compatibility
(i.e. an app compiled on 26 can also run on a phone having API level 26 or lower).

Considering your use-case, wouldn't a better approach be just to show the current app version? If you know the version, you could look up how/when it was created (via git tags, for example) and then find out the SDK version it was compiled with.

Android Studio API level error for Android Wear

I am trying to run and test a simple android application using android studio(version 3.0.1) on a smartwatch, I am getting the below error with respect to the gradle sync. (I am creating an new project by selecting the wear with the API level of 22 which is same as smartwatch API level).
Error:Execution failed for task ':app:processDebugManifest'.
Manifest merger failed : uses-sdk:minSdkVersion 22 cannot be smaller than version 23 declared in library [com.android.support:wear:26.1.0] C:\Users\Sai.gradle\caches\transforms-1\files-1.1\wear-26.1.0.aar\5b2a40104c2cc0843c9e44597771b49a\AndroidManifest.xml as the library might be using APIs not available in 22
Suggestion: use a compatible library with a minSdk of at most 22,
or increase this project's minSdk version to at least 23,
or use tools:overrideLibrary="android.support.wear" to force usage (may lead to runtime failures)
I have looked up for this error in most of the stackoverflow post's and they suggested to change the minimum SDK version in the build.GRADLE (app module) file in the defaultConfig section to 23, and the error doesn’t appear when I change the version to 23 as below.
defaultConfig {
applicationId "com.example.sai.wearexample"
minSdkVersion 23
targetSdkVersion 26
versionCode 1
versionName "1.0"
}
But, if I change the minSdkVersion version to 23 then there is the below error while I want to run the application on the smartwatch.
I have looked into many of the answers in the stackoverflow but I am not able to get any of the specific resolutions for this question. I am stuck in between these two errors, any help would be appreciated.

You should not use com.android.support:wear for api <23.
For the views you can add:
provided 'com.google.android.wearable:wearable:2.3.0'
compile 'com.google.android.support:wearable:2.3.0'
And change in your java and xml the code for use the tools of
com.google.android.wearable
instead
com.google.android.support:wearable
For example, use android.support.wearable.view.BoxInsetLayout instead of android.support.wear.widget.BoxInsetLayout.
I hope I have helped.

'Calling new methods on older versions' lint check not finding higher than minimum api calls in Android Studio

I'm developing an Android app on Android Studio and I'm calling a method from API level 19. My build.gradle looks like this:
android {
compileSdkVersion 24
buildToolsVersion '24.0.2'
productFlavors {
// Define separate dev and prod product flavors.
dev {
// dev utilizes minSDKVersion = 21 to allow the Android gradle plugin
// to pre-dex each module and produce an APK that can be tested on
// Android Lollipop without time consuming dex merging processes.
minSdkVersion 21
}
prod {
// The actual minSdkVersion for the application.
minSdkVersion 16
}
}
defaultConfig {
applicationId "com.myapp"
minSdkVersion 16
multiDexEnabled true
targetSdkVersion 24
versionCode 1
versionName "1.0"
}
}
I have no lint.xml files in my project, so no lint checks are overriden.
The problem is that the lint check "Calling new methods on older versions." doesn't find the method call for API level 19. If I open the build variants panel and select prodDebug or prodRelease the method gets underlined in red, but the project builds well. How can I get Android Studio to effectively show the aforementioned method in the analyze result or to block me from correctly building the project?
Edit
I found a way to search for methods not complying with the minimum SDK. By going to the Gradle panel on the right and running the lint task, an HTML report is generated, which finally shows the API 19 call along with other calls. Why is this not implemented into Android Studio?
Since this still does not work in Android Studio per se, but rather in Gradle, I'm not closing the question yet.

Gradle won't tell you if you are using the methods that are not supported in you minSDK if your compiled SDK version is not the minimum one. read more about it
So simply the solution is use lint feature i.e inspectcode
right click , either on project/class then => analyze=>inspectCode

Android application compatibility with old APIs

I created an app with the API 22 and I want to know if is necessary create a new project to make it compatible with the previous versions (for example with the API 19) or if I can do something simpler and efficient

If you're using gradle just set the minSdkVersion to the number you'd like to use:
defaultConfig {
applicationId "com.example.mypackage"
minSdkVersion 16
targetSdkVersion 24
versionCode 1
versionName "1.0"
}
in the app's build.gradle file

There are 2 way,
1) Set your "minSdkVersion" from gradle file
or
2) In Android Studio,
File --> Project Structure --> app (on left menu) --> Flavors
then set "Min Sdk Version"