Android: How to detect a directory in the assets folder?

Question

I'm retrieving files like this

String[] files = assetFiles.list("EngagiaDroid"); 

How can we know whether it is a file or is a directory?

I want to loop through the directories in the assets folder then copy all of its contents.

Answer 1

I think a more general solution (in case you have subfolders etc.) would be something like this (based on the solution you linked to, I've added it there too):

...

copyFileOrDir("myrootdir");

...

private void copyFileOrDir(String path) {
    AssetManager assetManager = this.getAssets();
    String assets[] = null;
    try {
        assets = assetManager.list(path);
        if (assets.length == 0) {
            copyFile(path);
        } else {
            String fullPath = "/data/data/" + this.getPackageName() + "/" + path;
            File dir = new File(fullPath);
            if (!dir.exists())
                dir.mkdir();
            for (int i = 0; i < assets.length; ++i) {
                copyFileOrDir(path + "/" + assets[i]);
            }
        }
    } catch (IOException ex) {
        Log.e("tag", "I/O Exception", ex);
    }
}

private void copyFile(String filename) {
    AssetManager assetManager = this.getAssets();

    InputStream in = null;
    OutputStream out = null;
    try {
        in = assetManager.open(filename);
        String newFileName = "/data/data/" + this.getPackageName() + "/" + filename;
        out = new FileOutputStream(newFileName);

        byte[] buffer = new byte[1024];
        int read;
        while ((read = in.read(buffer)) != -1) {
            out.write(buffer, 0, read);
        }
        in.close();
        in = null;
        out.flush();
        out.close();
        out = null;
    } catch (Exception e) {
        Log.e("tag", e.getMessage());
    }

}

Answer 2

You may use list method of AssetManager. Any directory in asset should have one file at least, empty directory will be ignored when building your application. So, to determine if some path is directory, use like this:

AssetManager manager = activity.getAssets();
try {
    String[] files = manager.list(path);
    if (files.length > 0) {
        //directory
    } else {
        //file
    }
} catch (Exception e) {
    //not exists.
}

Answer 3

I've discovered this variant:

try {
    AssetFileDescriptor desc = getAssets().openFd(path);  // Always throws exception: for directories and for files
    desc.close();  // Never executes
} catch (Exception e) {
    exception_message = e.toString();
}

if (exception_message.endsWith(path)) {  // Exception for directory and for file has different message
    // Directory
} else {
    // File
}

It's a more faster as .list()