iOS How to Close an App

With multi-tasking, apps no longer really close when you press the home button. It stays in the background and the OS automatically closes them when the device is low on memory and when it thinks the app is unlikely to be used in the near future. To force it to close for e.g. development testing purpose, follow the instructions on this page: http://support.apple.com/kb/ht5137

AWS DynamoDB Java API Gotcha

If you don't set the end-point, it will default to the US East Virginia region, resulting in an error saying the table can't be found.

The error message you'll get varies. If you have IAM setup to limit access for the user account to this specific DynamoDB table, then you'll get an "AccessDeniedException". Otherwise, you'll get a "ResourceNotFoundException".

If your DynamoDB is configured in the other regions, you'll have to set the End Point after creating the client e.g:

client = new AmazonDynamoDBClient(awsCredentials); client.setEndpoint("https://dynamodb.ap-southeast-1.amazonaws.com");

AWS DynamoDB ARN for IAM

To give access via IAM to a specific DynamoDB resource, define the ARN as follows:

arn:aws:dynamodb:<region>:<accountID>:table/<tablename>

AWS IAM Account ID

The account ID is needed to construct the ARN for IAM entries. AWS isn't being very clear about how to retrieve the account ID. It's actually the Account Number (with the hypens removed) that you see under your name in the "Manage Your Account" page (accessed via the "My Account" link in a drop down menu under your name on the top-right of the console).

Mac Show Hidden Files in Finder

I usually don't need this feature, as I can use the Terminal to work with hidden files, but when I needed to restore some hidden files from Time Machine, I needed to get Finder to show hidden files.

Here's a couple of links showing how it's done:

• http://howto.cnet.com/8301-11310_39-20062357-285/how-to-access-hidden-files-to-restore-in-time-machine/
• http://meinit.nl/restore-hidden-files-apple-mac-os-x-time-machine

iOS Simulator: View Files

If you ever need to look into the filesystem of an iOS Simulator to e.g. test file download features, here are some information as to how it's done:

• http://stackoverflow.com/questions/6480607/is-there-any-way-to-see-the-file-system-on-the-ios-simulator
• http://idevhub.com/where-is-the-iphone-simulator-filesystem-stored/