Tips & Tricks of Effective iOS Developers

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BEN SCHEIRMAN @subdigital

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Weekly Screencasts on iOS DEVELOPMENT $9/month

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Tips & Tricks of Effective iOS Developers

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? Effective

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effective |iˈfektiv| adjective ! successful in producing a desired or intended result

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! DEVELOPERS Effective

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! DEVELOPERS FIX PROBLEMS Effective

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! DEVELOPERS WRITE CODE FASTER Effective

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! DEVELOPERS CONFIDENTLY REFACTOR Effective

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! DEVELOPERS WRITE BETTER CODE Effective

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! DEVELOPERS WRITE FEWER BUGS Effective

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! DEVELOPERS GET THINGS DONE Effective

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! DEVELOPERS SHIP BETTER SOFTWARE Effective

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SHIP BETTER SOFTWARE

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ME?

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I aspire to be Effective

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Objective-C Tips

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Always use braces for conditionals if ([self isHungry]) { [self eatBurger]; } if ([self isHungry]) [self eatBurger]; if ([self isHungry]) [self eatBurger]; [self takeNap]; if ([self isHungry]) { [self eatBurger]; [self takeNap]; }

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if ((err = SSLHashSHA1.update(&hashCtx, &serverRandom)) != 0) goto fail; if ((err = SSLHashSHA1.update(&hashCtx, &signedParams)) != 0) goto fail; goto fail; if ((err = SSLHashSHA1.final(&hashCtx, &hashOut)) != 0) goto fail; ... ! fail: SSLFreeBuffer(&signedHashes); SSLFreeBuffer(&hashCtx); return err; Always use braces for conditionals

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@interface Player ! - (void)moveLeft; - (void)moveRight; - (void)jump; - (void)hit; ! @end Use Class Continuations for Private Properties @interface Player () @property CGFloat health; @property Texture *texture; @end ! @implementation Player … @end Player.h Player.m

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Use Class Continuations for Private Properties @interface ViewController () @property IBOutlet UILabel *label; @end ! @implementation ViewController … @end

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Use intention revealing method names - (NSDate *)nextDate:(NSDate *); - (NSDate *)nextBillingDateAfterDate:(NSDate *);

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Name single parameter BOOL arguments -(void)showPanel:(BOOL)animated; [self showPanel:NO];

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Name single parameter BOOL arguments -(void)showPanelAnimated:(BOOL)animated; [self showPanelAnimated:NO];

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Add Comment Documentation to Public Methods

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- (void)viewDidLoad { [self.fetchedResultsController performFetch:nil]; } Lazily Initialize Properties - (NSFetchedResultsController *)fetchedResultsController { if (_frc == nil) { _frc = [[NSFetchedResultsController alloc] initWithFetchRequest: self.fetchRequest ... ] } ! return _frc; }

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Lazily Initialize Properties - (NSFetchRequest *)fetchRequest { if (_fetchRequest == nil) { _fetchRequest = … } return _fetchRequest; }

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Lazily Initialize Properties - (void)didReceiveMemoryWarning { self.fetchResultsController = nil; self.fetchRequest = nil; … }

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Use Refactor Method judiciously - (UITableViewCell *)tableView:(UITableView *)tv cellForRowAtIndexPath:(NSIndexPath *) indexPath { UITableViewCell *cell = [tv dequeueReusableCellWithIdentifier:@“cell”]; NSArray *peopleInSection = self.sections[indexPath.section]; Person *person = peopleInSection[indexPath.row]; cell.textLabel.text = [NSString stringWithFormat:@“%@ %@“, person.firstName, person.lastName]; cell.detailTextLabel.text = person.email; return cell; }

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Use Refactor Method judiciously - (UITableViewCell *)tableView:(UITableView *)tv cellForRowAtIndexPath:(NSIndexPath *) indexPath { UITableViewCell *cell = [tv dequeueReusableCellWithIdentifier:@“cell”]; Person *person = [self personAtIndexPath:indexPath]; cell.textLabel.text = [NSString stringWithFormat:@“%@ %@“, person.firstName, person.lastName]; cell.detailTextLabel.text = person.email; return cell; }

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Use Refactor Method judiciously - (UITableViewCell *)tableView:(UITableView *)tv cellForRowAtIndexPath:(NSIndexPath *) indexPath { UITableViewCell *cell = [tv dequeueReusableCellWithIdentifier:@“cell”]; Person *person = [self personAtIndexPath:indexPath]; cell.textLabel.text = person.fullName; cell.detailTextLabel.text = person.email; return cell; }

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Use Refactor Method judiciously - (UITableViewCell *)tableView:(UITableView *)tv cellForRowAtIndexPath:(NSIndexPath *) indexPath { UITableViewCell *cell = [tv dequeueReusableCellWithIdentifier:@“cell”]; Person *person = [self personAtIndexPath:indexPath]; [self updateCell:cell forPerson:person]; return cell; }

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Understand Dependencies method1 method2

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Understand Dependencies

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Understand Dependencies

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Understand Dependencies

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Keep your dependencies in check OO is your friend

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objc-dependency-visualizer http://paultaykalo.github.io/objc-dependency-visualizer

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http://jomnius.blogspot.com/2012/01/dependency-graph-tool-for-ios-projects.html

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http://jomnius.blogspot.com/2012/01/dependency-graph-tool-for-ios-projects.html

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Reduce Dependencies by… Loose Coupling Programming to interfaces Dependency Inversion Reduce God Objects Reduce Singletons

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With Less Dependencies you can… Refactor Change your mind Change your implementation Add features

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“Ruthlessly modularize functionality. Design, implement, and package everything as if it were to be distributed as 3rd-party code”

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“Ruthlessly modularize functionality. Design, implement, and package everything as if it were to be distributed as 3rd-party code”

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Mattt Thompson

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Slim down your classes

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Slim down your classes

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Try to impose limits

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Challenge Yourself Photograph by Mikey Schaefer

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Max LOC for .m: ~150 Max LOC for method: 4-5 Cesare Rocchi

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Automate it

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awk

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find "${SRCROOT}" $-name "*.h" -or -name "*.m"$ -and $ -path "${SRCROOT}/Pods/*" -prune -o -print0 $ | xargs -0 wc -l | awk '$1 > 400 && $2 != "total" { for(i=2;i

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Xcode Tips

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Completing Methods

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“- ta”

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Label your views in Interface Builder

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Learn Keyboard Shortcuts Photo credit: Wikipedia

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⌘0

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⌘⌥0

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⌘⇧J

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⌘⇧Y

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⌘⇧C

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⌘⌃J ⌘⌃←

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Jump in Assistant, back

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⌘⌃E (Edit all in Scope)

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⌃I (Re-indent selection)

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So many to learn

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Pick 2 you don’t know

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Deliberately Practice them

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Repeat.

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Snippets

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Xcode / TextExpander

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“pns” @property (nonatomic, strong)

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“propint” @property (nonatomic, assign) NSInteger

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“propstr” @property (nonatomic, copy) NSString *

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“mark” #pragma mark -

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#pragma mark

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#pragma mark

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“tvds”

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“swf”

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“tvdel”

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“networkact” [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];

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Repetitive code? Boilerplate code? ! Make a snippet.

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Source Control Tips

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(git)

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Use the command line

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Leverage GUIs for specific tasks

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http://rowanj.github.io/gitx/ GitX

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Commits aren’t just ⌘S

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Commit in logical chunks.

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Write a good commit message

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http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html Capitalized, short (50 chars or less) summary ! More detailed explanatory text, if necessary. Wrap it to about 72 characters or so. In some contexts, the first line is treated as the subject of an email and the rest of the text as the body. The blank line separating the summary from the body is critical (unless you omit the body entirely); tools like rebase can get confused if you run the two together. ! Write your commit message in the imperative: "Fix bug" and not "Fixed bug" or "Fixes bug." This convention matches up with commit messages generated by commands like git merge and git revert. ! Further paragraphs come after blank lines. ! - Bullet points are okay, too ! - Typically a hyphen or asterisk is used for the bullet, followed by a single space, with blank lines in between, but conventions vary here ! - Use a hanging indent

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$ git log --oneline ! 9511f6c Add mixpanel gem 47a3e6d Add a sleep to not get throttled by facebook ce30dcb Kick Jenkins build 2e6802f Merge pull request #981 from DeliRadio/venue-favorites-rabls 99eb628 stub master account to avoid fail when run in test suite. b4e0435 before(:all) -> before(:each) to avoid certain test to fail when execute e4b10b6 Update schema 7b1e053 Fix banner check for venues in autocomplete 83ca7cb Update ci reporter 6eae32f Fix admin manages events spec. 7c8902b Add new line at the end of file so Github likes it. a153a48 Call Rails.application.eager_load! right before it is needed so that its 4a4d050 Refactoring test so it finishes faster. 4155ac6 fix crash when correcting country code from geolocated params 08c5bdb Proper auth token generation for facebook login: 4efaf1e Venue needs to have shareable_id and shareable_type implementation. Defa a9cdd7a Implemented a test to check shareable_id and shareable_type. Since Favor 9e1e6c2 fix after_party task syntax dde3ae9 add after_party task to fill in fb birthdays where we can 6e99a74 Implemented tests to check renderability of all ActiveRecord instance th b174af9 Added four templates that are required for favoritable items. 07218a0 year_of_birth, not birth_year be562bf update attribs from fb even for existing users 29041f0 Add logging to facebook oauth responses

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Branches are basically free

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REBASE Learn to

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master origin/master

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master origin/master

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master origin/master MERGE METHOD “git pull” by default

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master origin/master

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master origin/master REBASE METHOD

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99% of the time you want ! git pull --rebase

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Make this the default git config branch.autosetuprebase always

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Never rebase public branches

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git bisect

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git bisect start

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git bisect bad

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git checkout HEAD~15

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git bisect good

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git bisect bad

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git bisect bad

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git bisect good

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git bisect good

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git bisect good

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git bisect run

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Oops, I made a git mistake!

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git reflog

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Branch Per Feature

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Keep Master Releasable

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Don’t veer too far from working software

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“I attempt to keep the app in a working state as much as possible. That means test driving small changes, committing often, and only hooking things up to the UI when I think they're ready…”

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“… If I'm not in a position to push my code at least every hour or so, I feel like I haven't broken my work down properly”

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Stew Gleadow

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http://collectorcare.blogspot.com/

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http://cobcottagegifts.com/

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Effective Habits

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“I'm not a great programmer; I'm just a good programmer with great habits.” ! - Kent Beck

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Keep an improvement list ! !

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Have a side project ! !

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Read Other People’s Code

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“I form opinions about the code I study. Not all of it is good. I want to reflect on why I feel that way.”

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Jonathan Penn

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Learn how to ask for help

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Don’t ask ! Questions. 5

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Ask ! Question. 1

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Distill The Problem

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Reduce Variables

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Also works for:

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“Before asking for advice, take a careful look at what you know and what you are looking to have answered. Often that will put you in a spot where you answer your own question.” ! !

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Daniel Steinberg

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Program in other Languages

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“Don't just program in Objective C, make sure you regularly use another language. There is a lot we can learn from other technologies and communities” ! - Stew Gleadow ! !