kotlin android app development course, considering API level compatibility

In Android development, API levels are a very important concept. The API level identifies a specific version of the Android platform and defines the features and APIs available for use in apps. In this tutorial, we will delve into how to consider API level compatibility when developing Android apps using Kotlin. This will help you learn how to make your apps work smoothly across various Android devices.

1. Understanding API Levels

An API level is an integer associated with the version of the Android operating system. Each Android version has a specific API level, and the higher the level, the more new features and APIs are added. For example:

  • Android 4.0 (Ice Cream Sandwich) -> API Level 14
  • Android 5.0 (Lollipop) -> API Level 21
  • Android 6.0 (Marshmallow) -> API Level 23
  • Android 8.0 (Oreo) -> API Level 26
  • Android 10.0 -> API Level 29
  • Android 12.0 -> API Level 31

Understanding which features are supported only at specific API levels is essential. This ensures that your app runs well on specific Android versions.

2. Configuring the build.gradle

The first step in setting the API level in an Android project is to configure the build.gradle file. This file contains settings for the smooth build of the app. Here is an example of configuring the API level:

android {
    compileSdkVersion 31 // The most recent SDK level
    defaultConfig {
        applicationId "com.example.myapp"
        minSdkVersion 21 // Minimum supported API level
        targetSdkVersion 31 // API level the app should work well on
        versionCode 1
        versionName "1.0"
    }
}

compileSdkVersion defines the version of the SDK to be used for compiling the app, while minSdkVersion sets the minimum API level the app can be installed on. targetSdkVersion is the API level that the app expects to function on, and features may be restricted on devices below this level.

3. Writing Code with API Level Compatibility in Mind

When developing an app, the code should be written to be compatible across various API levels. During this process, you can use Build.VERSION.SDK_INT to check the current device’s API level and apply different logic accordingly. Here is an example of this:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
    // Code that runs only on Android 5.0 (Lollipop) and above
    val myView = MaterialButton(this)
} else {
    // Code that runs on Android 5.0 (Lollipop) and below
    val myView = Button(this)
}

3.1. Differentiating Functionality Through Runtime Checks

Since the features available can vary based on API levels, it is crucial to check for runtime permissions or the availability of specific features in your code. For example, the permissions required to request location information may vary depending on the API level.

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
    // Code to request permission
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.ACCESS_FINE_LOCATION), LOCATION_PERMISSION_REQUEST_CODE)
    }
} else {
    // Back in the days when permissions were not needed
    getLocation()
}

4. Alternatives for Legacy Support

Sometimes, there may be a need to support older API levels. In such cases, the Jetpack libraries can be utilized to handle legacy API support. Jetpack provides various Android architecture components and libraries that help you easily access necessary features for older devices.

4.1. Maintaining Compatibility Through Jetpack

For instance, using Jetpack libraries like ViewModel or LiveData allows for better management with less code, even on older API levels, contributing to the app’s stability.

class MyViewModel : ViewModel() {
    val myData: LiveData> = MutableLiveData()
    // Data processing code
}

5. Optimization and Testing

It is also important to test your app across various API levels. Using the Android Emulator allows you to conduct tests across different device configurations. It is advisable to repeatedly test various environments for each API level to identify potential issues in advance.

5.1. Real Device Testing

Testing on real devices is equally essential. By testing on various devices, you can identify compatibility issues that may arise and rectify them in advance.

Conclusion

In this tutorial, we dealt with how important API level compatibility is in Android app development using Kotlin. By understanding API levels and appropriately configuring the build.gradle file and writing code, you can ensure that your applications function smoothly across various Android devices. Furthermore, legacy support through Jetpack and thorough testing can help prevent issues beforehand.

We hope this helps you in your future journey of Kotlin Android app development!