Add slf4j logging for kotlin jvm and android

bdk-kotlin/android/build.gradle

@@ -1,6 +1,5 @@
 apply plugin: 'com.android.library'
 apply plugin: 'kotlin-android'
-//apply plugin: 'kotlin-android-extensions'
 apply plugin: 'maven-publish'
 
 android {
@@ -24,15 +23,7 @@ android {
     }
 }
 
-//task buildRust(type: Exec) {
-//    workingDir '../'
-//    commandLine './build.sh'
-//}
-
 afterEvaluate {
-//    android.libraryVariants.all { variant ->
-//        variant.javaCompileProvider.get().dependsOn(buildRust)
-//    }
 
     publishing {
         publications {
@@ -68,7 +59,9 @@ dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
     implementation 'androidx.appcompat:appcompat:1.3.0'
     implementation 'androidx.core:core-ktx:1.5.0'
-    
+    api "org.slf4j:slf4j-api:1.7.30"
+
+    androidTestImplementation 'com.github.tony19:logback-android:2.0.0'
     androidTestImplementation (project(':test-fixtures')) {
         exclude group: 'net.java.dev.jna', module: 'jna'
     }

bdk-kotlin/android/src/androidTest/assets/logback.xml

@@ -0,0 +1,14 @@
+<configuration>
+    <appender name="logcat" class="ch.qos.logback.classic.android.LogcatAppender">
+        <tagEncoder>
+            <pattern>%logger{12}</pattern>
+        </tagEncoder>
+        <encoder>
+            <pattern>[%-20thread] %msg</pattern>
+        </encoder>
+    </appender>
+
+    <root level="DEBUG">
+        <appender-ref ref="logcat" />
+    </root>
+</configuration>

bdk-kotlin/jvm/build.gradle

@@ -20,6 +20,9 @@ dependencies {
     implementation platform('org.jetbrains.kotlin:kotlin-bom')
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
     implementation "net.java.dev.jna:jna:5.8.0"
+    api "org.slf4j:slf4j-api:1.7.30"
+    testImplementation "ch.qos.logback:logback-classic:1.2.3"
+    testImplementation "ch.qos.logback:logback-core:1.2.3"
     testImplementation 'org.jetbrains.kotlin:kotlin-test-junit'
     testImplementation (project(':test-fixtures'))
 }

bdk-kotlin/test-fixtures/build.gradle

@@ -9,6 +9,7 @@ dependencies {
     implementation "net.java.dev.jna:jna:5.8.0"
     implementation (project(':jvm'))
     implementation 'org.jetbrains.kotlin:kotlin-test-junit'
+    api "org.slf4j:slf4j-api:1.7.30"
 }
 
 java {

bdk-kotlin/test-fixtures/src/main/java/org/bitcoindevkit/bdk/LibTest.kt

@@ -3,6 +3,8 @@ package org.bitcoindevkit.bdk
 import com.sun.jna.Native
 import org.junit.*
 import org.junit.Assert.assertEquals
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
 import kotlin.test.assertNotNull
 import kotlin.test.assertNull
 
@@ -13,6 +15,8 @@ import kotlin.test.assertNull
 abstract class LibTest {
 
     companion object {
+        private val log: Logger = LoggerFactory.getLogger(LibTest::class.java)
+        
         private val bdkFfi: Lib = Native.load("bdk_ffi", Lib::class.java)
         private lateinit var wallet_result: Lib.WalletResult_t
 
@@ -26,26 +30,26 @@ abstract class LibTest {
                 "wpkh([c258d2e4/84h/1h/0h]tpubDDYkZojQFQjht8Tm4jsS3iuEmKjTiEGjG6KnuFNKKJb5A6ZUCUZKdvLdSDWofKi4ToRCwb9poe1XdqfUnP4jaJjCB2Zwv11ZLgSbnZSNecE/1/*)"
 
             wallet_result = bdkFfi.new_wallet_result(name, desc, change)
-            //println("wallet created")
+            log.debug("wallet created")
         }
 
         @AfterClass
         @JvmStatic
         fun free_wallet() {
             bdkFfi.free_wallet_result(wallet_result)
-            //println("wallet freed")
+            log.debug("wallet freed")
         }
     }
 
     @Test
     fun wallet_sync_error() {
         val bad_wallet_result = bdkFfi.new_wallet_result("test", "bad", null)
-        //println("wallet result created")
+        log.debug("wallet result created")
         val sync_result = bdkFfi.sync_wallet(bad_wallet_result)
         val sync_err_pointer = bdkFfi.get_void_err(sync_result)
         assertNotNull(sync_err_pointer)
         val sync_err = sync_err_pointer!!.getString(0)
-        //println("wallet sync error $sync_err")
+        log.debug("wallet sync error $sync_err")
     }
 
     @Test
@@ -64,7 +68,7 @@ abstract class LibTest {
         
         bdkFfi.free_string_result(address_result)
         bdkFfi.free_string(address_pointer)
-        //println("address created from kotlin: $address")
+        log.debug("address created from kotlin: $address")
         assertEquals(address, "tb1qzg4mckdh50nwdm9hkzq06528rsu73hjxxzem3e")
     }
 }