InstantappLauncher.java

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val button = findViewById(R.id.button)
        val editText = findViewById(R.id.editText) as EditText

        button.setOnClickListener {
            val intent = Intent("com.google.android.instantapps.START")
            intent.addCategory(Intent.CATEGORY_BROWSABLE)

            // Instant apps need to end with a / or the urls don't work
            var text = editText.text.toString()
            if (!text.endsWith("/")) {
                text += "/"
            }
            intent.data = Uri.parse(text)
            startActivity(intent)
        }
    }
}