For loop causing android app to crash

Question

i'm having trouble figuring out why my app is crashing every time i open it. It's only when I uncomment the for loop.

I'm using this idea here to copy files from one directory to another

How to programmatically move, copy and delete files and directories on SD?

however this part (i tried both this way and the same way as in the link above, using children string, etc)

for (File file : files)
{
    CopyFile(file, target);
}

keeps causing my application to crash. I tried commenting out just this part and the app runs fine (it doesnt copy anything however as its not accessing a file)

Any ideas?

    private void CopyFile(File source, File target) throws IOException {



    if (source.isDirectory()){

        File[] files = source.listFiles();
        for (File file : files)
        {
            CopyFile(file, target);
        }

    } else {
        InputStream in = new FileInputStream(source);
        OutputStream out = new FileOutputStream(Environment.getExternalStorageDirectory());

        byte[] buf = new byte[1024];
        int len;
        while ((len = in.read(buf)) > 0){
            out.write(buf, 0, len);
        }
        in.close();
        out.close();

    }

Do you have the permissions to read and write from external storage? — Martin Cazares, Oct 10 '13 at 00:11
Could be for a number of reasons. Could you post the stacktrace? — Heinrisch, Oct 10 '13 at 00:11
Please post the stacktrace and the `Class` where the `for` loop resides. — Emmanuel, Oct 10 '13 at 00:12
Yes i have write permissions from external storage. I do not have any read/write permissions from root directory however, which is where im trying to access the file from (/data/data/ to be exact) I edited the original post — user1324674, Oct 10 '13 at 00:18

score 0 · Answer 1 · answered Oct 10 '13 at 00:38

0

You can't read anything in /data/data except from subdirectories controlled by your app.

/data/data/*packagename*/files

is the path returned by Context.getFilesDir()

/data

is the path returned by Environment.getDataDirectory().

Where exactly do you expect the files to be, and how did they get there originally?

answered Oct 10 '13 at 00:38

Joe Malin

8,621
1
23
18

Really? Interesting. How do things like root explorer and such do it then? – user1324674 Oct 10 '13 at 01:06

For loop causing android app to crash

1 Answers1