diff --git a/example/build.gradle b/example/build.gradle
index b8796b2..957959f 100644
--- a/example/build.gradle
+++ b/example/build.gradle
@@ -32,7 +32,7 @@ android {
 }
 
 dependencies {
-//    implementation project(path: ':fcl-android')
+    implementation project(path: ':fcl-android')
 
     implementation 'androidx.core:core-ktx:1.7.0'
     implementation 'androidx.appcompat:appcompat:1.4.1'
@@ -42,7 +42,7 @@ dependencies {
 
     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.5.2'
 
-    implementation 'com.github.Outblock:fcl-android:0.03'
+//    implementation 'com.github.Outblock:fcl-android:0.03'
 
     testImplementation 'junit:junit:4.13.2'
     androidTestImplementation 'androidx.test.ext:junit:1.1.3'
diff --git a/example/src/main/java/io/outblock/fcl/example/MainActivity.kt b/example/src/main/java/io/outblock/fcl/example/MainActivity.kt
index c421276..bba13e3 100644
--- a/example/src/main/java/io/outblock/fcl/example/MainActivity.kt
+++ b/example/src/main/java/io/outblock/fcl/example/MainActivity.kt
@@ -15,8 +15,9 @@ import androidx.core.content.ContextCompat
 import com.google.android.material.tabs.TabLayout
 import io.outblock.fcl.Fcl
 import io.outblock.fcl.provider.WalletProvider
-import io.outblock.fcl.utils.ioScope
-import io.outblock.fcl.utils.uiScope
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
 
 class MainActivity : AppCompatActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -46,7 +47,7 @@ class MainActivity : AppCompatActivity() {
         """.trimIndent()
         )
         findViewById<View>(R.id.button_query).setOnClickListener {
-            ioScope {
+            CoroutineScope(Dispatchers.IO).launch {
                 val cadence = edittext.text.toString()
                 val result = Fcl.query {
                     cadence(cadence)
@@ -54,17 +55,17 @@ class MainActivity : AppCompatActivity() {
                     arg { int(3) }
                     arg { address("0xba1132bc08f82fe2") }
                 }
-                uiScope { findViewById<TextView>(R.id.query_result_view).text = result }
+                CoroutineScope(Dispatchers.Main).launch { findViewById<TextView>(R.id.query_result_view).text = result }
             }
         }
     }
 
     private fun setupSignMessage() {
         findViewById<View>(R.id.button_sign_message).setOnClickListener {
-            ioScope {
+            CoroutineScope(Dispatchers.IO).launch {
                 val message = findViewById<EditText>(R.id.sign_message_edittext).text.toString()
                 val signature = Fcl.signMessage(message)
-                uiScope { findViewById<TextView>(R.id.signed_message_view).text = signature }
+                CoroutineScope(Dispatchers.Main).launch { findViewById<TextView>(R.id.signed_message_view).text = signature }
             }
         }
     }
@@ -91,11 +92,11 @@ class MainActivity : AppCompatActivity() {
 
         findViewById<View>(R.id.auth_button).setOnClickListener {
             val provider = if (tabLayout.selectedTabPosition == 0) WalletProvider.DAPPER else WalletProvider.BLOCTO
-            ioScope {
+            CoroutineScope(Dispatchers.IO).launch {
                 val auth = Fcl.authenticate(provider)
                 Log.d(TAG, "authenticate complete:$auth")
-                uiScope {
-                    Toast.makeText(this, "authenticate complete", Toast.LENGTH_SHORT).show()
+                CoroutineScope(Dispatchers.Main).launch {
+                    Toast.makeText(this@MainActivity, "authenticate complete", Toast.LENGTH_SHORT).show()
                     findViewById<TextView>(R.id.address).text = auth.address
                 }
             }
@@ -123,7 +124,7 @@ class MainActivity : AppCompatActivity() {
         )
 
         button.setOnClickListener {
-            ioScope {
+            CoroutineScope(Dispatchers.IO).launch {
                 val tid = Fcl.mutate {
                     cadence(editText.text.toString())
                     arg { string("Test2") }
@@ -131,7 +132,7 @@ class MainActivity : AppCompatActivity() {
                     gaslimit(1000)
                 }
                 Log.d(TAG, "tid:$tid")
-                uiScope {
+                CoroutineScope(Dispatchers.Main).launch {
                     txidView.text = tid
                     txidLayout.visibility = View.VISIBLE
                     viewOnFlowScanView.setOnClickListener {
@@ -144,7 +145,7 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
-    fun String.openInSystemBrowser(context: Context) {
+    private fun String.openInSystemBrowser(context: Context) {
         ContextCompat.startActivity(context, Intent(Intent.ACTION_VIEW, Uri.parse(this)), null)
     }
 
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/CoroutineUtils.kt b/fcl-android/src/main/java/io/outblock/fcl/utils/CoroutineUtils.kt
index 4beb1fb..fd12815 100644
--- a/fcl-android/src/main/java/io/outblock/fcl/utils/CoroutineUtils.kt
+++ b/fcl-android/src/main/java/io/outblock/fcl/utils/CoroutineUtils.kt
@@ -3,20 +3,20 @@ package io.outblock.fcl.utils
 import io.outblock.fcl.BuildConfig
 import kotlinx.coroutines.*
 
-fun ioScope(unit: suspend () -> Unit) = CoroutineScope(Dispatchers.IO).launch { execute(unit) }
+internal fun ioScope(unit: suspend () -> Unit) = CoroutineScope(Dispatchers.IO).launch { execute(unit) }
 
-suspend fun contextScope(unit: suspend () -> Unit) = withContext(Dispatchers.Main) { execute(unit) }
+internal suspend fun contextScope(unit: suspend () -> Unit) = withContext(Dispatchers.Main) { execute(unit) }
 
-fun uiScope(unit: suspend () -> Unit) = CoroutineScope(Dispatchers.Main).launch { execute(unit) }
+internal fun uiScope(unit: suspend () -> Unit) = CoroutineScope(Dispatchers.Main).launch { execute(unit) }
 
-fun uiDelay(delayMs: Long, unit: suspend () -> Unit) = CoroutineScope(Dispatchers.Main).launch {
+internal fun uiDelay(delayMs: Long, unit: suspend () -> Unit) = CoroutineScope(Dispatchers.Main).launch {
     delay(delayMs)
     execute(unit)
 }
 
-fun cpuScope(unit: suspend () -> Unit) = CoroutineScope(Dispatchers.Default).launch { execute(unit) }
+internal fun cpuScope(unit: suspend () -> Unit) = CoroutineScope(Dispatchers.Default).launch { execute(unit) }
 
-suspend fun repeatWhen(
+internal suspend fun repeatWhen(
     predicate: suspend () -> Boolean,
     block: suspend () -> Unit,
 ) {
@@ -25,7 +25,7 @@ suspend fun repeatWhen(
     }
 }
 
-suspend fun runBlockDelay(timeMillis: Long, block: suspend () -> Unit) {
+internal suspend fun runBlockDelay(timeMillis: Long, block: suspend () -> Unit) {
     val startTime = System.currentTimeMillis()
     block.invoke()
     val elapsedTime = System.currentTimeMillis() - startTime
diff --git a/fcl-android/src/main/java/io/outblock/fcl/utils/Log.kt b/fcl-android/src/main/java/io/outblock/fcl/utils/Log.kt
index 3d74dea..06d3235 100644
--- a/fcl-android/src/main/java/io/outblock/fcl/utils/Log.kt
+++ b/fcl-android/src/main/java/io/outblock/fcl/utils/Log.kt
@@ -5,27 +5,27 @@ import io.outblock.fcl.BuildConfig
 
 private val PRINT_LOG = BuildConfig.DEBUG
 
-fun logv(tag: String?, msg: Any?) {
+internal fun logv(tag: String?, msg: Any?) {
     log(tag, msg, Log.VERBOSE)
 }
 
-fun logd(tag: String?, msg: Any?) {
+internal fun logd(tag: String?, msg: Any?) {
     log(tag, msg, Log.DEBUG)
 }
 
-fun logi(tag: String?, msg: Any?) {
+internal fun logi(tag: String?, msg: Any?) {
     log(tag, msg, Log.INFO)
 }
 
-fun logw(tag: String?, msg: Any?) {
+internal fun logw(tag: String?, msg: Any?) {
     log(tag, msg, Log.WARN)
 }
 
-fun loge(tag: String?, msg: Any?) {
+internal fun loge(tag: String?, msg: Any?) {
     log(tag, msg, Log.ERROR)
 }
 
-fun loge(msg: Throwable?, printStackTrace: Boolean = true) {
+internal fun loge(msg: Throwable?, printStackTrace: Boolean = true) {
     log("Exception", msg?.message ?: "", Log.ERROR)
     if (PRINT_LOG && printStackTrace) {
         msg?.printStackTrace()