How to produce Trusted Web Activity (TWA) for your website

A. Create some Empty Project in android studio

B. Keystore

The keystore is to sign the APK file. Keystore is to make .aab and .apk file.

Create keystore file

keytool -genkey -v -keystore lab_example.keystore -alias lab_example -keyalg RSA -keysize 2048 -validity 10000

Now we have something like this

File lab_example.keystore

Info:

alias: lab_example
key store password: example
key password: example

Sign

in same directory to get the SHA-256 run this

keytool -list -v -keystore lab_example.keystore -alias lab_example -storepass example -keypass example | grep SHA256

Make assetlinks.json

Go here to make the assetlinks.json file

Upload the assetlinks.json to your website

Put that file into https://yourwebsite.com/.well-known/assetlinks.json

C. Need to write to your code

Shortcut to open file in Android Studio Shift + Cmd + O

File MainActivity.kt

package com.example.yourAppName

import android.net.Uri
import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.tooling.preview.Preview
import com.example.yourAppName.ui.theme.yourAppNameTheme
import com.google.androidbrowserhelper.trusted.TwaLauncher

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        // Launch the TWA
        launchTwa("https://example.com")

        setContent {
            yourAppNameTheme {
                // A surface container using the 'background' color from the theme
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background
                ) {
                    EmptyScreen()
                }
            }
        }
    }

    private fun launchTwa(url: String) {
        // Create an instance of TwaLauncher and launch the TWA with the specified URL
        val twaLauncher = TwaLauncher(this)
        twaLauncher.launch(Uri.parse(url))

        // Optionally finish the activity so it doesn’t stay in the back stack
        finish()
    }
}

@Composable
fun EmptyScreen() {
    // This can be an empty Composable, or you can show a message or loading screen if needed
}

@Preview(showBackground = true)
@Composable
fun GreetingPreview() {
    yourAppNameTheme {
        EmptyScreen()
    }
}

File build.gradle.kts

dependencies {
    implementation ("androidx.browser:browser:1.4.0")
    implementation ("com.google.androidbrowserhelper:androidbrowserhelper:2.4.0")
}

How to build the APK & AAB file

In google play console you need the .aab file

Try to product signed .apk release to try on your device.

Upload to Google Play Console

Before you upload to Google Play Console

You need to prepare some information:

• Need some privacy policy page. eg. https://yourwebsite.com/privacy
• Need screenshots of the app, at least 3 screenshots

After google review

• Need 20 email address, for tester. Then they need to keep the app installed for 14 days.

Yeay your app ready