Warning: Attempt to present … on … while a presentation is in progress!

There is a warning message in Xcode, the Apple iOS development environment that can have many different causes. Warning: Attempt to present … on … while a presentation is in progress! In my case Xcode displayed the warning because a button called the same view twice. When I deleted the action associated with the Touch […]

Xcode app development troubleshooting

This post is a collection of common error messages you may receive during application development in Xcode. Error message Receiver ‘NSManagedObjectContext’ for class message is a forward declaration Solution Add #import <CoreData/CoreData.h> to the … – Prefix.pch Prefix header file in the Supporting Files folder  

Save an image in the Xcode iPhone simulator

When you are testing an app in the Xcode iOS Simulator sometimes you need to select an image in the photo library. To add images to Photos in the Xcode iOS Simulator Run you app in the iOS iPhone Simulator In the Hardware menu select Home to hide your app Open the Safari browser in […]

Apple Objective-C programming fundamentals. Working with Data, Part 2, Create the data model

In this part of the series we will continue the development of our data store app that we set up in the first part of the series. Create the Data Model Open your sample application that you created in the first part Open the Project Navigator Select the Supporting Files group Click the plus (+) […]

Apple Objective-C programming fundamentals. Working with Data, Part 1, The App

This article will guide you to create an app that stores data on the user’s device. To create our sample app to store data on the user’s device Start Xcode, the Apple IDE for IOS development Create a new project Open the AppDelegate.h file and enter the following into the @interface section before the @end @property […]

Apple Objective-C programming fundamentals. Working with Dates

When you need to display date and time on your app’s screen you need an easy way to convert NSDate objects to NSString objects. Objective-C  contains methods to do the conversion, but the syntax is not simple. It is much easier to create a method that does the conversion and call that in a central […]

Apple Objective-C programming fundamentals. Creating Segues in the Storyboard

Segue types Segues are connections between views, so one view can call the other when the user pushes a button, or any specific object. The Modal Segue When the two views do not need to share information, like a login screen The Push Segue The push segue can pass data between the views and handle […]

Apple Objective-C programming fundamentals – Part 1 – The language.

To write an application for an Apple device (iPhone, iPod, iPadn, Macintosh) Apple recommends the Ojbective-C language. Xcode, the Apple development environment (IDE) supports the usage of Objective-C. This article summarizes the basics of Objective-C for beginners of that language. It is helpful if you already have some programming experience, otherwise some terms will require […]

Using the Apple Xcode development environment

View two files side-by-side Open the Project Navigator Click the first file in the Navigator Option-Click the second file in the Navigator The two files are displayed next to each other, so you can compare them and copy code between them. Using tabs In the Apple Xcode IDE you can use tabs to quickly switch […]