Working on trying to pass objects, unwrap them to C/C++ types, do something, then return the result as an object. Now I get why people say JNI is tricky

app/src/main/cpp/Demo.cpp

@@ -251,7 +251,7 @@ Java_com_example_mear_activities_LoginActivity_retrieveSong(
 extern "C"
 JNIEXPORT jobject
 JNICALL
-Java_com_example_mear_activities_LoginActivity_retrieveUserCredentials(
+Java_com_example_mear_repositories_UserRepository_retrieveUserCredentials(
         JNIEnv *env,
         jobject thisObj,
         jstring dataPath
@@ -275,6 +275,43 @@ Java_com_example_mear_activities_LoginActivity_retrieveUserCredentials(
     return userObj;
 }
 
+extern "C"
+JNIEXPORT jobject
+JNICALL
+Java_com_example_mear_repositories_UserRepository_logUser(
+        JNIEnv *env,
+        jobject thisObj,
+        jobject user,
+        jstring apiUri ) {
+    jclass userClass = env->GetObjectClass(user);
+    //auto tok = env->CallObjectMethod(token, env->GetMethodID(tokenClass, "setAccessToken", "(Ljava/lang/String;)V"));
+    auto passwordField = env->GetFieldID(userClass, "getPassword", "(Ljava/lang/String;)V");
+    //auto passwordM = env->CallObjectMethod(user, env->GetMethodID(userClass, "password", "(Ljava/lang/String;)V"));
+    //auto passwordMOne = env->CallObjectMethod(user, env->GetMethodID(userClass, "getPassword", "(Ljava/lang/String;)V"));
+    auto password = env->GetObjectField(user, passwordField);
+    //auto username = env->CallObjectMethod(user, env->GetMethodID(userClass, "setUsername", "(Ljava/lang/String;)V"));
+    auto usernameField = env->GetFieldID(userClass, "setUsername", "(Ljava/lang/String;)V");
+    auto username = env->GetObjectField(user, usernameField);
+
+    const std::string usr = env->GetStringUTFChars((jstring)username, nullptr);
+    const std::string pass = env->GetStringUTFChars((jstring)password, nullptr);
+    const std::string api = env->GetStringUTFChars(apiUri, nullptr);
+
+    model::Token token(fetchToken(usr, pass, api));
+
+    jclass tokenClass = env->FindClass( "com/example/mear/models/Token");
+    jmethodID jconstructor = env->GetMethodID( tokenClass,  "<init>", "()V" );
+    jobject tokenObj = env->NewObject( tokenClass, jconstructor );
+
+    jmethodID tokenAccess = env->GetMethodID( tokenClass,  "setAccessToken", "(Ljava/lang/String;)V" );
+
+    jstring title = env->NewStringUTF(token.accessToken.c_str());
+
+    env->CallVoidMethod(tokenObj, tokenAccess, title);
+
+    return tokenObj;
+}
+
 
 extern "C"
 JNIEXPORT jstring
@@ -299,7 +336,7 @@ Java_com_example_mear_activities_LoginActivity_logUser(
 extern "C"
 JNIEXPORT jboolean
 JNICALL
-Java_com_example_mear_activities_LoginActivity_isUserTableEmpty(
+Java_com_example_mear_repositories_UserRepository_isUserTableEmpty(
         JNIEnv *env,
         jobject thisObj,
         jstring dataPath
@@ -313,7 +350,7 @@ Java_com_example_mear_activities_LoginActivity_isUserTableEmpty(
 extern "C"
 JNIEXPORT jboolean
 JNICALL
-Java_com_example_mear_activities_LoginActivity_doesDatabaseExist(
+Java_com_example_mear_repositories_BaseRepository_doesDatabaseExist(
         JNIEnv *env,
         jobject thidObj,
         jstring dataPath

app/src/main/java/com/example/mear/activities/LoginActivity.kt

@@ -11,7 +11,9 @@ import kotlinx.android.synthetic.main.content_login.*
 import org.jetbrains.anko.toast
 
 import com.example.mear.models.Song
+import com.example.mear.models.Token
 import com.example.mear.models.User
+import com.example.mear.repositories.UserRepository
 
 class LoginActivity : BaseServiceActivity() {
 
@@ -24,12 +26,12 @@ class LoginActivity : BaseServiceActivity() {
 
     private external fun retrieveSong(tok: String, api: String, songId: Int): Song
 
-    private external fun retrieveUserCredentials(path: String): User
+    //private external fun retrieveUserCredentials(path: String): User
 
     private external fun logUser(usr: String, pass: String, api: String): String
 
-    private external fun doesDatabaseExist(path: String): Boolean
-    private external fun isUserTableEmpty(path: String): Boolean
+    //private external fun doesDatabaseExist(path: String): Boolean
+    //private external fun isUserTableEmpty(path: String): Boolean
 
     private external fun pathIteratorDemo(path: String)
     private external fun saveUserCredentials(username: String, password: String, appDir: String)
@@ -41,8 +43,9 @@ class LoginActivity : BaseServiceActivity() {
         setSupportActionBar(toolbar)
 
         val pa = appDirectory()
-        if (doesDatabaseExist(pa) && !isUserTableEmpty(pa)) {
-            val usr = retrieveUserCredentials(pa)
+        val usrRepo = UserRepository()
+        if (usrRepo.databaseExist(pa) && !usrRepo.isTableEmpty(pa)) {
+            val usr = usrRepo.retrieveCredentials(pa)
             username.setText(usr.username)
             password.setText(usr.password)
         }
@@ -71,22 +74,26 @@ class LoginActivity : BaseServiceActivity() {
 
         val saveCred = saveUserCred.isChecked
 
-        val usernameStr = username.text.toString()
-        val passwordStr = password.text.toString()
         var apiUriStr = apiUri.text.toString()
+        val usr = User()
+        usr.username = username.text.toString()
+        usr.password = password.text.toString()
 
         if (apiUriStr.isEmpty()) {
-            apiUriStr = ""
+            apiUriStr = "https://www.soaricarus.com"
         }
 
-        val token = logUser(usernameStr, passwordStr, apiUriStr)
+        val myToken = Token(logUser(usr.username, usr.password, apiUriStr))
+        //val token = logUser(usernameStr, passwordStr, apiUriStr)
+        val usrRepo = UserRepository()
+        //val newToken = usrRepo.fetchToken(usr, apiUriStr)
 
         try {
             val songId = 4
-            val song = retrieveSong(token, apiUriStr, songId)
+            val song = retrieveSong(myToken.accessToken, apiUriStr, songId)
             val pa = appDirectory()
-            if (saveCred && isUserTableEmpty(pa)) {
-                saveUserCredentials(usernameStr, passwordStr, pa)
+            if (saveCred && usrRepo.isTableEmpty(pa)) {
+                saveUserCredentials(usr.username, usr.password, pa)
             }
             //startActivity(Intent(this, IcarusSongActivity::class.java))
         }

app/src/main/java/com/example/mear/repositories/BaseRepository.kt

@@ -0,0 +1,17 @@
+package com.example.mear.repositories
+
+open class BaseRepository {
+
+    companion object {
+        init {
+            System.loadLibrary("native-lib")
+        }
+    }
+
+
+    private external fun doesDatabaseExist(path: String): Boolean
+
+    fun databaseExist(path: String): Boolean {
+        return doesDatabaseExist(path)
+    }
+}

app/src/main/java/com/example/mear/repositories/UserRepository.kt

@@ -0,0 +1,37 @@
+package com.example.mear.repositories
+
+import com.example.mear.models.Token
+import com.example.mear.models.User
+
+class UserRepository : BaseRepository() {
+
+    private external fun logUser(user: User, apiUri: String) : Token
+
+    private external fun retrieveUserCredentials(path: String) : User
+
+    private external fun isUserTableEmpty(path: String): Boolean
+
+    private external fun saveUserCredentials(username: User)
+
+
+    fun fetchToken(user: User, apiUri: String): Token {
+        val usr = logUser(user, apiUri)
+
+        return usr
+    }
+
+
+    fun retrieveCredentials(path: String): User {
+        return retrieveUserCredentials(path)
+    }
+
+
+    fun isTableEmpty(path: String): Boolean {
+        return isUserTableEmpty(path)
+    }
+
+
+    fun saveCredentials(user: User) {
+        saveUserCredentials(user)
+    }
+}