How to set up your Mac for Rails Development

In this post I will guide you through everything necessary to get your freshly set up Mac — using Leopard or Snow Leopard — ready for Ruby on Rails Development.

Things we’ll install:

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Set background image of UITableView

How to set a background image of a UITableView is a very often and common question. Today we will try to answer this.

There are two ways to solve this problem:

  1. Create a new UIView – lets call the view V – set the background image of V and embed a UITableView – lets call it TV – within V. Now set the background color of TV to [UIColor clearColor] and do so for all UITableViewCells. Everything seems to work well but you have to handle some tasks (regarding the UITableView) on your own now like deselcting the currently selected UITableViewCell when returning from a prior pushed view.
  2. The second approach requires less effort but creates a not so pretty side-effect. You can simply create a new UIView, set its background image and send this view to the back of the UITableView. If you do so the background image scrolls with the UITableView. So this solution should only be used if you do not have to many cells, i.e. to create a simple menu screen in a grouped style within your app.

For those guys, implementing the second solution, the following code would be helpful. Put it i.e. in your - (void) viewDidLoad; method or further initialization of your view controller.

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Create custom activity indicator for your iPhone App

Have you ever dreamed of your own custom activity indicator within your iPhone App? The class UIImageView provides a very useful and simple way to implement such a thing. The only thing you have to do is to:

  • Provide a number of images that reflect your indicator animation.
  • Create a new UIImageView instance and set images and animation duration.
  • Position your custom activity indicator within your current view.

To demonstrate the whole process I quickly created some images (I am sure you will style them better than me) which will serve for our animation.

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UIImageView Fade-In and Fade-Out (pulsating) Animation

Today just a small code snippet to create a nice fade-in-fade-out (or call it pulsating) effect on a given UIImage. To accomplish this within a UIView you have to do only a few steps:

  • Create a UIImageView containing your image.
  • Create the animation with its properties.
  • Set the animation for the specific layer containing your image.

In words of code you will have to do something like the following:

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Jolein iPhone App published

Its done! On 21st, July 2009 we submitted the first iPhone App to the Apple App Store and today it was approved! Our App is called Jolein and is used as a basic management frontend for the stunning Jolein platform.

Jolein Main Menu Currently the Jolein App is only available in german language but further language support is planned. While the Jolein platform is used for efficient staff coordination, resource and qualification managment and service scheduling the associated Jolein App supports following tasks:

  • Overview of staff and easy communication with them
  • Task managment
  • Messaging service
  • Overview of own companies
  • Easy staff coordination and service planning
  • Conflict managment

Over here are some more pictures of the App to get a better imagination for the user interface and the App’s capabilities. On the first screen you can see how a new task for a given employee is created and on the second screen a duty roaster is illustrated for a given company and day.

Jolein Add Task Jolein Duty Roaster

For more information visit the Jolein platform or view the App description within the Apple App Store. Jolein im App Store

Android Bluetooth on steroids with the NDK and bluez

NOTE: this is not a general solution and might not work on every phone or future version of the DKs, but it is still a great way for any prototyping purposes :)

Unfortunately the SDK currently only supports a small set of the Bluetooth stack. As we wanted to integrate some of our hardware gadgets (over SPP/RFCOMM) with our Dev Phone 1, we needed to digg a little deeper. So here is what you want to do to get it working.

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Android NDK logging

So after the first few mini steps into the NDK the first thing you will probably notice missing, is a way to retrieve log messages through logcat. To be able to do this you need to do two things:

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Check internet connection on iPhone

People (especially iPhone developers) watch out! If your iPhone app relies on any kind of internet back-end-service, don’t forget to check if the service is available and even more to check if a internet connection is currently possible (for instance there is no network or the iPhone is in flight mode).

If you don’t provide enough information to your users, that your iPhone app needs a valid internet connection or your back-end-service is currently not available, Apple may reject your iPhone App.

You will find several examples how to achieve that at the web. The following code I found several times at stackoverflow.com could be very useful for you:

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UIButton in UITableView Footer

Once upon a time, there was a pretty UITableView within my iPhone user interface. This table included some UITableViewCells which were used to provide some information of a specific data record. At this time I thought that it would be nice to have a big red delete button at the end of the table (like we can locate it in the edit mask of the Apple Calendar App).

To realize such a button at the end of the table we can simply use the ability to define our own footer view for each section within a UITableView. The next steps describe how we can do that for a single section.

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UITableViewCell with detail label

Creating some UITableViewCells with a main label and a secondary detail label (as we allready knew from the e.g. settings menu on the iPhone) to show some kind of a selected value isn’t very complicated but annoying anyway. The ways to do that were either to create a label as subview programmatically or you used the Interface Builder to provide a nib file including the cell.

This common task was greatly facilitated by the introduction of the new iPhone SDK 3.0, which now supports a few styles for UITableViewCells (see UITableViewCellStyle for more information). The following example shows how to create such a simple table cell:

//create a cell with the style UITableViewCellStyleValue1
UITableViewCell *cell = [[UITableViewCell alloc]
			 initWithStyle:UITableViewCellStyleValue1
			 reuseIdentifier:@"yourReuseIdentifier"];
 
//the main label will be shown on the left side
[cell.textLabel	setText:@"mainLabel"];
 
//the detail label will be shown on the right side
//in blue color, right-aligned and in a smaller font size
[cell.detailTextLabel setText:@"detailLabel"];

The result of this will be something like that:

tableviewcell_with_detail