More than UI
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The document provides an overview of common classes, frameworks, and concepts in Objective-C and Cocoa Touch including NSString, NSArray, NSDictionary, file handling, persistence, threads, timers, XML parsing, HTTP connections, collections, autorelease pools, persistence to files, application directories, using delegates, and using accelerometers.
![Autorelease pool Pool of autorelease objects Restrict the scope of autorelease objects Must to use in thread methods Call retain to extend the scope of variable -(void)anyMethod{ NSAutoreleasePool *pool = [[NSAuto… // allocate a lot of memory (autorelease) [pool release]; }](https://image.slidesharecdn.com/morethanui-090318075652-phpapp02/85/More-than-UI-5-320.jpg)
![Autorelease - A Scenario (NSString*)someMethod{ NSString *stringToReturn = nil; for (int i = 0; i < someLargeNumber; i++) { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSString *string = ...; string = [string stringByAppendingString:...]; if ([string someCondition]) { stringToReturn = [string retain]; } [pool release]; if (stringToReturn) break; } return [stringToReturn autorelease]; }](https://image.slidesharecdn.com/morethanui-090318075652-phpapp02/85/More-than-UI-6-320.jpg)
![Typical NSThread Use Case - (void)someAction:(id)sender { // Fire up a new thread [NSThread detachNewThreadSelector:@selector(doWork:) withTarget:self object:someData]; } - (void)doWork:(id)someData { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; [someData doLotsOfWork]; // Message back to the main thread [self performSelectorOnMainThread:@selector(allDone:) withObject:[someData result] waitUntilDone:NO]; [pool release]; }](https://image.slidesharecdn.com/morethanui-090318075652-phpapp02/85/More-than-UI-9-320.jpg)
More than UI
- 1. More than UI Sujith Krishnan 30SS
- 2. Foundation framework Common Classes String NSString NSMutableString Array NSArray NSMutableArray Dictionary NSDict.. NSMutableDict.. File Handling NSFileManager Persistance NSKeyedArchiver Thread NSThread Timer NSTimer XML NSXmlParser HTTP Connection NSURLReqest
- 3. Collections – Array & Dictionary Retain the objects Available as mutable and immutable Direct persistence – writeToFile Generic – can hold any objects
- 4. Autorelease ??? Framework take care of releasing the object Factory methods are autorelease methods Can call autorelease on any object Write methods which will return autorelease objects
- 5. Autorelease pool Pool of autorelease objects Restrict the scope of autorelease objects Must to use in thread methods Call retain to extend the scope of variable -(void)anyMethod{ NSAutoreleasePool *pool = [[NSAuto… // allocate a lot of memory (autorelease) [pool release]; }
- 6. Autorelease - A Scenario (NSString*)someMethod{ NSString *stringToReturn = nil; for (int i = 0; i < someLargeNumber; i++) { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSString *string = ...; string = [string stringByAppendingString:...]; if ([string someCondition]) { stringToReturn = [string retain]; } [pool release]; if (stringToReturn) break; } return [stringToReturn autorelease]; }
- 7. Persistence Saving object state to a file Should implement encoding methods Key – Value NSKeyedArchiver NSKeyedUnarchiver Save in document directory Can use SQLite3 also
- 8. \tmp temporary files used by f/w \Documents user files \Library application preferences, settings etc.. Application Directories
- 9. Typical NSThread Use Case - (void)someAction:(id)sender { // Fire up a new thread [NSThread detachNewThreadSelector:@selector(doWork:) withTarget:self object:someData]; } - (void)doWork:(id)someData { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; [someData doLotsOfWork]; // Message back to the main thread [self performSelectorOnMainThread:@selector(allDone:) withObject:[someData result] waitUntilDone:NO]; [pool release]; }
- 10. Delegates Define delegate methods @required & @optional Multiple object and single delegate definition Object comparison Use of tag
- 12. Format Specifiers Same as what we use for rest of OOP %@ - for NSString , Object , Date etc… Can use positional specifiers IEEE print specifications