Can't create folder on external storage on android

Question

My development phone is a Nexus 5, running Android 4.4.2.

In my application, I am attempting to create a folder on external storage that wi

Answer 1

Typically, I do this:

/**
 * Return a dedicated directory named "MyApp" at the top of external storage
 */
public static file getDataDir() {
    File sdcard = Environment.getExternalStorageDirectory();
    if( sdcard == null || !sdcard.isDirectory() ) {
        // TODO: warning popup
        Log.w(TAG, "Storage card not found " + sdcard);
        return null;
    }
    File dataDir = new File(sdcard, "MyApp");
    if( !confirmDir(dataDir) ) {
        // TODO: warning popup
        Log.e(TAG, "Unable to create " + dataDir);
        return null;
    }
    return dataDir;
}   

private static boolean confirmDir(File dir) {
    if (dir.isDirectory()) return true;  // already exists
    if (dir.exists()) return false;      // already exists, but is not a directory
    return dir.mkdirs();                 // create it
}       

Also, add this permission to your manifest:

If you want private storage (typically under /data/) for your app (not on sdcard), then look into getDir(), getFilesDir(), fileList(), openFileInput(), openFileOutput(), etc.

There are also helper functions to get private directories within the sdcard for API 8 and above: getExternalFilesDir(), getExternalCacheDir(), etc.