android - i/o file

[Kori]

I know, this is not android forum, but after three days and nights i want to try everything.

My sfml/android test game is almost done. Last thing is game save state. But i have totally no idea how to implement it. I already tried C stdio.h and c++ streams, getting path from ANativeActivity::externalDataPath
and much more. Is it possible at all to read/write a .txt file using only ndk? Thanks in advance.

[Laurent]

What's the problem? Could you get a detailed error code or message that would help to figure out what's wrong?

What does ANativeActivity::externalDataPath contain? If it refers to the SD card, make sure you have one inserted

And which version of Android does your device use?

[Kori]

Testing on 2.3.7 and 4.4.2.
I try both, with externalDataPath  and externalDataPath.
To combine the default path with my file name i write something like that:

strcpy(name,asset->internalDataPath);
strcat(name, "/cnf.png");

I also trying just "/data/data/com.example.sfml/cnf.png", "/sdcard/cnf.png" and other similar path.

.png extension is to prevent file from being compressed. Also tested with .mp3, .txt, and without any extension.

Next, I was trying to read using ">>" from c++ or fscanf(stream, "%s", var"); from C
Always result is same,  crash with lovely SIGSEGV when reading starts. My "cnf" file is in assets folder and in main project folder. Now, I have't any concept how write/read function should looks like.

I hope you understand me,really sorry if something sounds unfriendly/unkindly, I still don't operate English very well.

[DarkRoku12]

Hope this links help you:

http://developer.android.com/training/basics/data-storage/files.html
http://stackoverflow.com/questions/11294487/android-writing-saving-files-from-native-code-only

[Mario]

Have you had a closer look at logcat? It should tell you more, not just some segfault.

[Kori]

It's a standard segfault, because i am trying to open non-existing file.

http://stackoverflow.com/questions/11294487/android-writing-saving-files-from-native-code-only
Yes, that's the answer, but i don't know how to implement it. Changing default int main with  void android_main(struct android_app* state) and moving this into NatwiveActivity.cpp throw
 "Description   Resource   Path   Location   Type
make.exe: *** [obj/local/armeabi-v7a/libsfml-example.so] Error 1   NativeActivity          C/C++ Problem"

If my logic is proper, android_app must be taken from main function, and is required to get file path.

So, easy fopen() won't be working? I must do it using NDK API? It's much harder than making game on PC....

[Mario]

Correct, it's not exposed yet right now, so you'd have to modify SFML's source to expose the native activity. A patch is in the works (I have it here, just lacks commit and some proper documentation). You should be able to use usual file streams, but you'll have to set the proper permission in your AndroidManifest.xml file.

[Kori]

   
I already had something like that:
     

(click to show/hide)

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
     <uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE"/>
     <uses-permission android:name="android.permission.READ_INTERNAL_STORAGE"/>

Modifying code is out of range of my newbie skills, especially in NDK. Last thing which I do, will be rewrite code on other system. My Windows is pretty freakish.

[Mario]

No worries, a branch (and pull request) will be up soon™.

[Kori]

I can't wait, you are doing awesome job (whole SFML team) .

short (hope last) question:

You should be able to use usual file streams,

Now or using possibility of access to NativeActivity in future? If now, i just can't solve the right path.
Thank you for your help.

[Mario]

Now, but I haven't really experimented with that. It might require you to figure out the actual paths (which might be hard without the native activity).

[Kori]

No, hardcoded path is imo bad idea. After sleep on in, i can't figure all possibly path on all android devices. I just sit down and wait for commit or try to read value from /proc/pid/cmdline. Better be patient than loosing another week on google research.

@BIG EDIT
Sorry,your pain in neck back for a moment. I promise, it's last time in this month (probably).

IT'S ALIVE. It's looking awful but works. SFML code is more readable than I guess. Brutally added NativeActivity pointer solve the problem. But...
Now i can't run it on IOS, right? I need last simply/short answer, is it will be hard to recompile it for Iphone ?