Cannot open file through JNI

asked 2015-10-26 10:16:42 -0500

alexiosk gravatar image

updated 2015-10-26 10:17:29 -0500

I have copied a txt file in my device's sdcard. In the Java side of my Android app (i.e. I can open the file through this code:

    StringBuilder text = new StringBuilder();
    try {
        File sdcard = Environment.getExternalStorageDirectory();
        File file = new File(sdcard,"/android-opencv/file.txt");

        BufferedReader br = new BufferedReader(new FileReader(file));
        String line;
        while ((line = br.readLine()) != null) {
    catch (IOException e) {


In my cpp file I try to open the same file doing the following:

  FILE* file = fopen("/storage/emulated/0/android-opencv/file.txt","r+");
  if (file != NULL)
        return env->NewStringUTF("Opened file");
        return env->NewStringUTF("Error!");

I have added reading permissions in the AndroidManifest.xml:

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

and I have checked the file path of the external storage directory that it is "/storage/emulated/0/"

Any ideas why this might be happening?

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