Android SD card on emulator writing fails with IOException EROFS (Read-only filesystem), have correct permission

Question

My android app can't write a file to the AVD's SD card, here's the code:

    File root = Environment.getExternalStorageDirectory();

    Log.w("sdcard", "root.canWrite() = " + root.canWrite());

    try {           
        File myFile = new File(root + File.pathSeparator + "mysdfile.txt");
        myFile.createNewFile();
        FileOutputStream fOut = new FileOutputStream(myFile);
        OutputStreamWriter myOutWriter = new OutputStreamWriter(fOut);
        myOutWriter.append("testing testing 123");
        myOutWriter.close();
        fOut.close();
    } catch (IOException e) {
        Log.w("ExternalStorage", "Error writing", e);
    }

root.canWrite() returns true, then this exception is raised:

java.io.IOException: open failed: EROFS (Read-only file system)

The manifest file has the WRITE_EXTERNAL_STORAGE permission (direct child of manifest):

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

I've also tried remounting the SD card in the AVD shell using:

mount -o remount rw /mnt/sdcard

...but to no avail. The AVD also has the "SD card support" flag set. Not sure what to do from here, any ideas?

Answer 1

To anyone interested, the problem was that I had made an sdcard.iso image and had eclipse passing that to the AVD as the -sdcard command line argument. For whatever reason, the image was read-only. Fixed the problem by clearing the command line args and editing the AVD to start with a new sd card of size 512mb, rather than a file.