Sample Android app on Kotlin

android/.gitignore

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+*.iml
+.gradle
+/local.properties
+/.idea/caches
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+/.idea/navEditor.xml
+/.idea/assetWizardSettings.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+local.properties

android/app/.gitignore

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+/build

android/app/build.gradle.kts

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+plugins {
+    alias(libs.plugins.androidApplication)
+    alias(libs.plugins.jetbrainsKotlinAndroid)
+    alias(libs.plugins.daggerHilt)
+    alias(libs.plugins.kotlinKapt)
+}
+
+android {
+    namespace = "com.zk.android.app"
+    compileSdk = 34
+
+    defaultConfig {
+        applicationId = "com.zk.android.app"
+        minSdk = 24
+        targetSdk = 33
+        versionCode = 1
+        versionName = "1.0"
+        //TODO Insert your key here
+        //buildConfigField("String", "PRIVATE_KEY", "\"<WALLET_PRIVATE_KEY>\"")
+    }
+    flavorDimensions.add("default")
+
+    productFlavors {
+        create("mainnet") {
+            applicationIdSuffix = ".debug"
+            buildConfigField("String", "RPC_ETH_URL", "\"https://rpc.ankr.com/eth\"")
+            buildConfigField("String", "ZK_ERA_URL", "\"https://mainnet.era.zksync.io\"")
+            buildConfigField("String", "ZK_ERA_SOCKET", "\"wss://mainnet.era.zksync.io/ws\"")
+        }
+        create("sepolia") {
+            buildConfigField("String", "RPC_ETH_URL", "\"https://rpc.ankr.com/eth_sepolia\"")
+            buildConfigField("String", "ZK_ERA_URL", "\"https://sepolia.era.zksync.dev\"")
+            buildConfigField("String", "ZK_ERA_SOCKET", "\"wss://sepolia.era.zksync.dev/ws\"")
+        }
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
+        }
+    }
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+    buildFeatures {
+        viewBinding = true
+        buildConfig = true
+    }
+}
+
+dependencies {
+
+    //Zk
+    implementation(libs.zksync)
+    implementation(libs.web3j.core)
+    implementation(libs.web3j.crypto)
+
+    implementation(libs.androidx.core.ktx)
+    implementation(libs.androidx.core.splashscreen)
+    implementation(libs.androidx.appcompat)
+    implementation(libs.androidx.constraintlayout)
+    implementation(libs.androidx.navigation.fragment.ktx)
+    implementation(libs.androidx.navigation.ui.ktx)
+    implementation(libs.lifecycle.viewmodel.ktx)
+    implementation(libs.lifecycle.runtime.ktx)
+
+    implementation(libs.material)
+    implementation(libs.orbit.viewmodel)
+    implementation(libs.lottie)
+
+    // Dependency injection
+    implementation(libs.hilt.android)
+    kapt(libs.hilt.compiler)
+    kapt(libs.androidx.hilt.compiler)
+    implementation(libs.hilt.navigation.fragment)
+}

android/app/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile
+
+# JSR 305 annotations are for embedding nullability information.
+-dontwarn javax.annotation.**
+
+# A resource is loaded with a relative path so the package of this class must be preserved.
+-keeppackagenames okhttp3.internal.publicsuffix.*
+-adaptresourcefilenames okhttp3/internal/publicsuffix/PublicSuffixDatabase.gz
+
+# Animal Sniffer compileOnly dependency to ensure APIs are compatible with older versions of Java.
+-dontwarn org.codehaus.mojo.animal_sniffer.*
+
+# OkHttp platform used only on JVM and when Conscrypt and other security providers are available.
+-dontwarn okhttp3.internal.platform.**
+-dontwarn org.conscrypt.**
+-dontwarn org.bouncycastle.**
+-dontwarn org.openjsse.**

android/app/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <uses-permission android:name="android.permission.INTERNET" />
+
+    <application
+        android:allowBackup="true"
+        android:dataExtractionRules="@xml/data_extraction_rules"
+        android:fullBackupContent="@xml/backup_rules"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:name=".ZkSynApp"
+        android:theme="@style/AppTheme.Starting"
+        tools:targetApi="33">
+        <activity
+            android:name=".presentation.MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

android/app/src/main/java/com/zk/android/app/ZkSynApp.kt

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+package com.zk.android.app
+
+import android.app.Application
+import dagger.hilt.android.HiltAndroidApp
+
+@HiltAndroidApp
+class ZkSynApp : Application()

android/app/src/main/java/com/zk/android/app/di/ZkModule.kt

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+package com.zk.android.app.di
+
+import com.zk.android.app.BuildConfig
+import com.zk.android.app.network.ZkConfig
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import io.zksync.protocol.ZkSync
+import org.web3j.crypto.Credentials
+import org.web3j.protocol.Web3j
+import org.web3j.protocol.http.HttpService
+import javax.inject.Singleton
+
+
+@Module
+@InstallIn(SingletonComponent::class)
+class ZkModule {
+
+    @Provides
+    @Singleton
+    fun provideConfig(): ZkConfig {
+        return ZkConfig(
+            BuildConfig.RPC_ETH_URL,
+            BuildConfig.ZK_ERA_URL,
+            BuildConfig.ZK_ERA_SOCKET,
+            BuildConfig.PRIVATE_KEY
+        )
+    }
+
+    @Provides
+    @Singleton
+    fun provideWeb3j(config: ZkConfig): Web3j {
+        return Web3j.build(HttpService(config.rpc))
+    }
+
+    @Provides
+    @Singleton
+    fun provideZkSync(config: ZkConfig): ZkSync {
+        return ZkSync.build(HttpService(config.url))
+    }
+
+    @Provides
+    @Singleton
+    fun provideCredentials(config: ZkConfig): Credentials {
+        return Credentials.create(config.privateKey)
+    }
+}

android/app/src/main/java/com/zk/android/app/domain/balance/BalanceModelDomain.kt

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+package com.zk.android.app.domain.balance
+
+import java.math.BigInteger
+
+
+data class BalanceModelDomain (
+    val l1Balance: BigInteger,
+    val l2Balance: BigInteger,
+)

android/app/src/main/java/com/zk/android/app/domain/balance/GetBalanceUseCase.kt

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+package com.zk.android.app.domain.balance
+
+import com.zk.android.app.network.WalletProvider
+import com.zk.android.app.utils.sendSafe
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.withContext
+import java.math.BigInteger
+import javax.inject.Inject
+
+
+class GetBalanceUseCase @Inject constructor(
+    private val walletProvider: WalletProvider
+) {
+
+    suspend fun getBalance(): Result<BalanceModelDomain> = withContext(Dispatchers.IO) {
+        val wallet = walletProvider.create().getOrElse {
+            return@withContext Result.failure(it)
+        }
+
+        val l1Balance: BigInteger = wallet.balanceL1.sendSafe().getOrElse {
+            return@withContext Result.failure(it)
+        }
+        val l2Balance: BigInteger = wallet.balance.sendSafe().getOrElse {
+            return@withContext Result.failure(it)
+        }
+
+        return@withContext Result.success(
+            BalanceModelDomain(
+                l1Balance,
+                l2Balance
+            )
+        )
+    }
+}

android/app/src/main/java/com/zk/android/app/domain/deposit/DepositModelDomain.kt

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+package com.zk.android.app.domain.deposit
+
+import com.zk.android.app.domain.balance.BalanceModelDomain
+
+
+data class DepositModelDomain (
+    val newBalance: BalanceModelDomain
+)

android/app/src/main/java/com/zk/android/app/domain/deposit/DepositUseCase.kt

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+package com.zk.android.app.domain.deposit
+
+import com.zk.android.app.domain.balance.GetBalanceUseCase
+import com.zk.android.app.network.WalletProvider
+import com.zk.android.app.utils.toWei
+import com.zk.android.app.utils.waitForTransactionReceiptSafe
+import io.zksync.transaction.type.DepositTransaction
+import io.zksync.utils.ZkSyncAddresses
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import java.math.BigInteger
+import javax.inject.Inject
+
+
+class DepositUseCase @Inject constructor(
+    private val walletProvider: WalletProvider,
+    private val balanceUseCase: GetBalanceUseCase
+) {
+
+    suspend fun deposit(amount: Float): Result<DepositModelDomain> = withContext(Dispatchers.IO) {
+        val wallet = walletProvider.create().getOrElse {
+            return@withContext Result.failure(it)
+        }
+
+        val sendAmount: BigInteger = amount.toWei()
+
+        val transaction = DepositTransaction(ZkSyncAddresses.ETH_ADDRESS, sendAmount)
+        val hash = wallet.deposit(transaction).sendAsync().join().result
+        wallet.transactionReceiptProcessorL1.waitForTransactionReceiptSafe(hash)
+
+        val newBalance = balanceUseCase.getBalance().getOrElse {
+            return@withContext Result.failure(it)
+        }
+
+        return@withContext Result.success(DepositModelDomain(newBalance))
+    }
+}

android/app/src/main/java/com/zk/android/app/network/WalletProvider.kt

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+package com.zk.android.app.network
+
+import androidx.annotation.WorkerThread
+import io.zksync.protocol.ZkSync
+import io.zksync.protocol.account.Wallet
+import org.web3j.crypto.Credentials
+import org.web3j.protocol.Web3j
+import javax.inject.Inject
+
+
+class WalletProvider @Inject constructor(
+    private val web3: Web3j,
+    private val zkSync: ZkSync,
+    private val credentials: Credentials
+) {
+
+    @WorkerThread
+    //TODO can we use single Wallet instance?
+    fun create(): Result<Wallet> {
+        return runCatching { Wallet(web3, zkSync, credentials) }
+    }
+}

android/app/src/main/java/com/zk/android/app/network/ZkConfig.kt

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+package com.zk.android.app.network
+
+
+data class ZkConfig(
+    val rpc: String,
+    val url: String,
+    val socket: String,
+    val privateKey: String
+)

android/app/src/main/java/com/zk/android/app/presentation/MainActivity.kt

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+package com.zk.android.app.presentation
+
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+import androidx.navigation.findNavController
+import androidx.navigation.ui.AppBarConfiguration
+import com.zk.android.app.R
+import com.zk.android.app.databinding.ActivityMainBinding
+import dagger.hilt.android.AndroidEntryPoint
+
+@AndroidEntryPoint
+class MainActivity : AppCompatActivity() {
+
+    private lateinit var appBarConfiguration: AppBarConfiguration
+    private lateinit var binding: ActivityMainBinding
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        setTheme(R.style.Theme_ZkSyncApp)
+        super.onCreate(savedInstanceState)
+
+        binding = ActivityMainBinding.inflate(layoutInflater)
+        setContentView(binding.root)
+
+        val navController = findNavController(R.id.nav_host_fragment_content_main)
+        appBarConfiguration = AppBarConfiguration(navController.graph)
+    }
+}