How to know internal memory size in android?

This is my code,

private String memSize(String path){
    StatFs stat = new StatFs(path);
    long blockSize = stat.getBlockSize();
    long availableBlocks = stat.getAvailableBlocks();
    long freeBlocks = stat.getFreeBlocks();
    long countBlocks = stat.getBlockCount();
    String fileSize = Formatter.formatFileSize(this, availableBlocks * blockSize);
    String maxSize = Formatter.formatFileSize(this, countBlocks * blockSize);

    String info = path.toString()
                    + "\nblockSize : " + Long.toString(blockSize)
                    + "\navailableBlocks : " + Long.toString(availableBlocks)
                    + "\nfreeBlocks : " + Long.toString(freeBlocks)
                    + "\nreservedBlocks : " + Long.toString(freeBlocks - availableBlocks)
                    + "\ncountBlocks : " + Long.toString(countBlocks)
                    + "\nspace : " + fileSize + " / " + maxSize
                    + "\n\n";
    return info;
}

I test my function with path /data and /sdcard and it works

But when path is / (I understand it is root path), this is开发者_如何学运维 result.

• blockSize: 4096
• availableBlocks: 0
• freeBlocks: 0
• reservedBlocks: 0
• countBlocks: 0
• space: 0.00B / 0.00B

I think root path is SuperUser area. May need some permission to access.

My phone is already rooted. Could you show me what I should do next step ?

Thank you.

References

• http://developer.android.com/reference/android/os/StatFs.html
• android internal phone storage

Your internal storage is not mounted in / it's in /data dir. android internal phone storage