Daniel Duan's Articles About Cocoa Touch

Daniel Duan's Articles About Cocoa Touch https://duan.ca/tag/cocoa-touch/ tableView:didSelectRowAtIndexPath: In Two Lines You have a <code>UITableViewController</code> with a couple of static cells, you want to invoke some code for each cell in the delegate. Here's a quick way to do it: <pre><code> - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { SEL action = (SEL[]){@selector(method1), @selector(method2)}[indexPath.row]; ((void (*)(id, SEL))[self methodForSelector: action])(self, action); } </code></pre> It's got everything you love about C and Objective-C: array literals, function pointers, casting, selectors and something called <a href="http://www.cocoawithlove.com/2008/02/imp-of-current-method.html">IMPs</a>. This piece of code maps selected cells to methods by putting methods by indexing selectors in a C array. Why all the fuss on the second line? wouldn't a simple <code>performSelector:</code> work? The short answer is: to show the compiler that we are responsible adults. You can read more about it [here](SO Answer); Sat, 03 May 2014 13:42:00 -0600 https://duan.ca/2014/05/03/tableview58didselectrowatindexpath58-in-two-lines/ https://duan.ca/2014/05/03/tableview58didselectrowatindexpath58-in-two-lines/ Generating Xcode Build Number From Git The build version number in an Xcode project (CFBundleVersion in Info.plist) must be a monotonically increasing string for each archive submitted to the App Store. Neglection of this requirement will result in an error during the binary upload. Some automation will help avoiding this issue. First, we want to generate this version number from our version (duh) control system (VCS) each time our target gets built. My VCS of choice is Git, users of other systems just need to get a increasing number from their code history. On a *nix system, this command will count the number of commits on 'develop' branch up until HEAD: <pre><code> git rev-list develop | wc -l </code></pre> This is a very good candidate for our build number, for longer history generally correlates to later builds. Next, we make Xcode automatically run this command and use its result as the build number. Go to project navigator, select your build target under the project icon, click Build Phases, select Editor→Add Build Phase→Add Run Script Build Phase in the menu. Remove the content in editor of the new Run Script phase and replace it with: <pre><code>revnum=`git rev-list develop | wc -l` echo "#define BUILD_NUMBER $revnum" > InfoPlist.h touch InfoPlist.h </code></pre> Go to build settings, change value of Preprocess Info.plist File to "YES". Add "InfoPlist.h" to Info.plist Preprocessor Prefix File→release. We ask Xcode to run our command and save its result as a "#define" in a header file when it builds the project. This is done so that we can replace the "hardcoded" build number with the name of the constant: Open Info.plist, Double click the value of Bundle Version and replace it with <pre><code>BUILD_NUMBER </code></pre> There's only one issue left: <code>BUILD_NUMBER</code> is now saved in InfoPlist.h. Its value comes from our commit history. So we want to exclude this piece of information as part of our commit history (I'll leave the reason as an exercise for the reader). Ignore this file by adding "InfoPlist.h" to .gitignore (or that of your other VCS). To recap, when you build the project now, Xcode will find out how many commits are in the history, define it in a header file as <code>BUILD_NUMBER</code>, which gets used as the build number. As long as you keep with with version control, the build number problem goes away. Sun, 29 Sep 2013 15:50:50 -0600 https://duan.ca/2013/09/29/generating-xcode-build-number-from-git/ https://duan.ca/2013/09/29/generating-xcode-build-number-from-git/