Category: iPhone app

1. Selector
http://stackoverflow.com/questions/3482344/what-actually-is-a-selector

An example
http://stackoverflow.com/questions/10758926/add-selector-to-uibutton
[button addTarget:yourObject action:@selector(yourMethod:) forControlEvents:UIControlEventTouchUpInside];

2. NSNotifications
In a way (and in syntax too) it’s similar to Selector, but used in different settings.

example here
http://www.cocoanetics.com/2009/08/love-to-be-notified/

3. Delegate methods
e.g., UIAlert view, UITextField delegate

customized method (example)
http://www.raywenderlich.com/29474/ipad-for-iphone-developers-101-in-ios-6-custom-input-view-tutorial

4. Blocks
https://developer.apple.com/library/mac/#featuredarticles/BuildingWithBlocks/_index.html

example
http://stackoverflow.com/questions/7180552/implementing-a-method-taking-a-block-to-use-as-callback

5. GCD
My favorite example here.
http://www.fieryrobot.com/blog/2010/07/10/a-watchdog-timer-in-gcd/

Combinations of some of the above, e.g, blocks (GCD) with notification

1) This puzzelled me for a while, my macbook air run out of space often. I was trying to use the build “Finder” to find large files, delete files and some unused apps, to no avail. I did some more google and used this Mac App “FindSpace”. And I found this directory /var/vm has some large swap files. Aha. Found the culprit. This article from osxdaily has more explanation.

2) Old Macbook heat. My 3 years old macbook air recently has the problem of overheat. It heated up fairly quickly after using 10 to 15 minutes. Did some google and found this one described my symptom well. The solution appears to be “SMC reset”. I did it yesterday and it works better at least for now…

(01-02-2017) I found chrome can take a lot space too, as well as the iTunes (iPhone) backup file (appears under mobile sync). Also the MacBook Pro retina has similar battery issue (cannot charge), did Smc reset, worked a while. Eventually had to send to Apple Store for a complete fix.

Recently I need to create some customized textfield to input numbers and text on iPad. I don’t like the default keyboard on iPad because it takes too much of the screen, and in some cases covers up the input field.

1) From iphonedevsdk: What is proper way to do UITextField text change call back? (this also mentioned by stackoverflow)

[textField addTarget:self action:@selector(textFieldDidChange:) forControlEvents:UIControlEventTouchDown];

The downside of this approach is: it takes a press (a tap and hold) to trigger the event.

2) InputView
Create a customized view such as this one at raywenderlich, then set the inputView of textfield. I used this approach to create a number pad that used to only input numbers. There is some limit to this approach as well: the location of customized input view is usually fixed, and in my case (a double picker) for text field (table cell), that is not ideal. I was using pop over controller (again raywenderlich), combined with approach 1, the user does not like the “hold”. After I changed to approach 2, the user does not like the fixed location of input view. So I did more research, and eventually I found the following approach that works for me.

One tip: make sure lock the input view, otherwise it will mess up things after iPad rotation.
– (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return NO;
}

3) self delegate, UITextFieldDelegate

Make sure do this in viewDidLoad (or other place initialize the text field):
myTextField.delegate = self;

This way I could have both “single tap” and the pop over controller.

I need to create a .NET web service consumable by iOS device. Did some research and found out WCF Restful service is the way to go. I used the following examples (tutorials) to construct my web service.

0) Basic Resource Service (link here).
This is basically a self hosting web service run in a main program. A good starting point to learn dataContract, webHttp, etc.

1) I need to change from a console app to a web service, and host on IIS, for this refer to
project 1
and
2(Space Service, a WCF web service app)

2) I need to combine 2 services into one program, and I referred to endPoint.tv plural sight podcast “Building RESTfil services with WCF”

The video above mentioned the httputil.js, HTTP POST/PUT utility, which is handy to test “POST” method. Another tool I used to test GET/POST, is “fiddler”.

A Guide to Designing and Building RESTful Web Services with WCF 3.5, also by Aaron Skonnard, Pluralsight

Essentially here we need to design a scheme (end points) for hosting multiple services.

3) Database connection, I used sql client, which is pretty vanilla.

4) Use pretty path instead of port number (routing service, refer to SimpleREST service again)

Also “code project” example
http://www.codeproject.com/Articles/105273/Create-RESTful-WCF-Service-API-Step-By-Step-Guide