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How to apply a filter to an image in ImageView in Kotlin Android

How to apply a filter to an image in ImageView in Kotlin Android.

Here's a detailed step-by-step tutorial on how to apply a filter to an image in an ImageView using Kotlin in Android:

Step 1: Set up the project​

  • Create a new Android project in Android Studio.
  • Make sure you have the necessary dependencies added in your project's build.gradle file.

Step 2: Add an ImageView to your layout​

  • Open the layout file (e.g., activity_main.xml) and add an ImageView element.
  • Set the desired height and width for the ImageView.
  • Optionally, set an image source for the ImageView using the src attribute.

Step 3: Create a filter resource file​

  • Right-click on the res folder in the project hierarchy and create a new resource file of type "color".
  • Give the file a name, such as "image_filter.xml".
  • In the XML file, define the desired filter using the <color> tag and specify the desired color values.

Step 4: Apply the filter programmatically​

  • Open the Kotlin file for your activity (e.g., MainActivity.kt).
  • Get a reference to the ImageView using findViewById or view binding.
  • Load the filter resource file using ContextCompat.getColorFilter().
  • Apply the filter to the ImageView using the colorFilter property.

Here's an example code snippet:

// Step 4: Apply the filter programmatically
class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // Step 4.1: Get a reference to the ImageView
        val imageView = findViewById<ImageView>(R.id.imageView)

        // Step 4.2: Load the filter resource file
        val filterColor = ContextCompat.getColorFilter(this, R.color.image_filter)

        // Step 4.3: Apply the filter to the ImageView
        imageView.colorFilter = filterColor
    }
}

Step 5: Run the app​

  • Build and run the app on an emulator or physical device.
  • The ImageView should now display the image with the applied filter.

That's it! You have successfully applied a filter to an image in an ImageView using Kotlin in Android. You can experiment with different filter colors and apply them to achieve different visual effects in your app.