get working folder from android java class

Author: Shivansps

code/cfile/cfile.cpp

@@ -32,7 +32,6 @@
 #include "osapi/osapi.h"
 #include "parse/encrypt.h"
 #include "cfilesystem.h"
-#include <SDL_system.h>
 
 #include <limits>
 
@@ -188,24 +187,8 @@ int cfile_init(const char *exe_dir, const char *cdrom_dir)
 	#ifndef __ANDROID__
 		strncpy(buf, exe_dir, CFILE_ROOT_DIRECTORY_LEN - 1);
 	#else
-		//Android gets the working folder path from the cmdline argument, if not present fallback to SDL path
 		(void)exe_dir;
-		extern char* Cmdline_working_folder;
-		if (Cmdline_working_folder != nullptr)
-		{
-			strncpy(buf, Cmdline_working_folder, CFILE_ROOT_DIRECTORY_LEN - 1);
-		} 
-		else
-		{
-			// fallback
-			const char* android_path = SDL_AndroidGetExternalStoragePath();
-			if (android_path == nullptr) {
-				os::dialogs::Message(os::dialogs::MESSAGEBOX_ERROR,
-					"Freespace Open needs permission to access the external storage.");
-				return 1;
-			}
-			snprintf(buf, CFILE_ROOT_DIRECTORY_LEN, "%s/files", android_path);
-		}
+		strncpy(buf, os_get_working_folder_path().c_str(), CFILE_ROOT_DIRECTORY_LEN - 1);
 	#endif
 
 	buf[CFILE_ROOT_DIRECTORY_LEN - 1] = '\0';

code/cmdline/cmdline.cpp

@@ -242,9 +242,6 @@ Flag exe_params[] =
 #ifdef WIN32
 	{ "-fix_registry",	"Use a different registry path",				true,	0,									EASY_DEFAULT,					"Troubleshoot", "http://www.hard-light.net/wiki/index.php/Command-Line_Reference#-fix_registry", },
 #endif
-#ifdef __ANDROID__
-	{ "-working_folder",	"Change working folder in Android",			true,	0,									EASY_DEFAULT,					"Android", "http://www.hard-light.net/wiki/index.php/Command-Line_Reference#-working_folder", },
-#endif
 
 	//flag					launcher text								FSO		on_flags							off_flags						category		reference URL
 	{ "-voicer",			"Enable voice recognition",					true,	0,									EASY_DEFAULT,					"Experimental",	"http://www.hard-light.net/wiki/index.php/Command-Line_Reference#-voicer", },
@@ -586,12 +583,6 @@ cmdline_parm output_script_json_arg("-output_script_json", nullptr, AT_NONE);	//
 cmdline_parm output_script_luastub_arg("-output_script_lua", nullptr, AT_NONE); // mjnmixael
 cmdline_parm generate_controlconfig_arg("-controlconfig_tbl", nullptr, AT_NONE);	
 
-// Android
-#ifdef __ANDROID__
-cmdline_parm wfolder_arg("-working_folder", "Sets the working folder when launching as a library in Android", AT_STRING, true);
-char* Cmdline_working_folder = nullptr;
-#endif
-
 // Deprecated flags - CommanderDJ
 cmdline_parm deprecated_spec_arg("-spec", "Deprecated", AT_NONE);
 cmdline_parm deprecated_glow_arg("-glow", "Deprecated", AT_NONE);
@@ -2422,12 +2413,6 @@ bool SetCmdlineParams()
 		Cmdline_multithreading = abs(multithreading.get_int());
 	}
 
-	#ifdef __ANDROID__
-	if (wfolder_arg.found()) {
-		Cmdline_working_folder = wfolder_arg.str();
-	}
-	#endif
-
 	return true; 
 }
 

code/cmdline/cmdline.h

@@ -169,8 +169,4 @@ extern void removeWindowModeOption();
 extern void removeResolutionOption();
 extern void removeResolutionVROption();
 
-//Android Exclusive
-#ifdef __ANDROID__
-extern char* Cmdline_working_folder;
-#endif
 #endif

code/osapi/osapi.cpp

@@ -28,6 +28,12 @@
 #include <sys/types.h>
 #endif
 
+#ifdef __ANDROID__
+#include <SDL_system.h>
+#include <SDL.h>
+#include <jni.h>
+#endif
+
 namespace
 {
 	const char* ORGANIZATION_NAME = "HardLightProductions";
@@ -840,3 +846,63 @@ SCP_string os_get_config_path(const SCP_string& subpath)
 	return ss.str();
 }
 
+/*
+	  Special functions for Android
+*/
+
+#ifdef __ANDROID__
+SCP_string os_get_working_folder_path()
+{
+	SCP_string wfp{};
+	 
+	//Get the JNI Environment pointer and current Activity instance via SDL
+    JNIEnv* env = (JNIEnv*)SDL_AndroidGetJNIEnv();
+    jobject activity = (jobject)SDL_AndroidGetActivity();
+    
+    if (env && activity) {
+    	// Locate the Java class (GameActivity on KnossosNET)
+    	jclass ga = env->GetObjectClass(activity);
+    	if(ga) {
+    		// Get the methodID (activity, methodName, signature);
+    		// "()Ljava/lang/String;" means it takes no paramenters and returns a string 
+    		jmethodID methodId = env->GetStaticMethodID(ga, "getWorkingFolder", "()Ljava/lang/String;");
+			if (methodId) {
+				jstring jString = (jstring)env->CallStaticObjectMethod(ga, methodId);
+				if (jString) {
+					const char* workingFolder = env->GetStringUTFChars(jString, 0);
+					wfp = SCP_string(workingFolder);
+					env->ReleaseStringUTFChars(jString, workingFolder);
+					env->DeleteLocalRef(jString);
+				} else {
+					mprintf(("Couldn't get the jString.\n"));
+				}
+			} else {
+				mprintf(("Couldn't get the methodID.\n"));
+			}
+			env->DeleteLocalRef(ga);
+    	} else {
+    		mprintf(("Couldn't get java class.\n"));
+    	}
+    } else {
+    	mprintf(("Couldn't get JNI enviroment or activity.\n"));
+    }
+    
+	if (wfp.empty()) {
+		mprintf(("Couldn't get working folder path from Java class, reverting to SDL default.\n"));
+		// Fallback to app space on internal storage
+		const char* fallbackPath = SDL_AndroidGetExternalStoragePath();
+		if (fallbackPath) {
+			wfp = SCP_string(fallbackPath);
+			wfp += "/files/"; 
+		}
+	}
+	
+	// Ensure path ends with a dir separator
+	if (!wfp.empty() && (wfp.back() != DIR_SEPARATOR_CHAR)) {
+		wfp += DIR_SEPARATOR_CHAR;
+	}
+	mprintf(("Using working folder: %s\n", wfp.c_str()));
+	return wfp;
+}
+#endif
+

code/osapi/osapi.h

@@ -91,6 +91,14 @@ bool os_is_legacy_mode();
  */
 SCP_string os_get_config_path(const SCP_string& subpath = "");
 
+/*
+	 Special functions for Android
+*/
+#ifdef __ANDROID__
+// Get working folder absolute path from Android Java Class
+SCP_string os_get_working_folder_path();
+#endif
+
 namespace os
 {
 	/**