iphone OS Overview

Transcription

1 Founda'on Framework

2 iphone OS Overview

3 iphone OS Overview

4 iphone OS Overview

5 iphone OS Overview

6 iphone OS Overview

7 iphone OS Overview

8 iphone Development Environment

9 Cocoa in the architecture of ios

10 Cocoa Touch Architecture

11 Founda'on Framework Value and collec'on classes User defaults Archiving No'fica'ons Tasks, 'mers, threads File system, pipes, I/O, bundles

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14 NSObject Root class Implements many basics Memory management Introspec'on Object equality

15 Adopted Protocols NSObject autorelease class conformstoprotocol: descrip'on hash isequal: iskindofclass: ismemberofclass: isproxy performselector: performselector:withobject: performselector:withobject:withobject: release respondstoselector: retain retaincount self superclass zone

16 Class Introspec'on You can ask an object about its class Class myclass = [myobject class]; NSLog(@"My class is %@", [myobject classname]); Tes'ng for general class membership (subclasses included): if ([myobject iskindofclass:[uicontrol class]]) { // something } Tes'ng for specific class membership (subclasses excluded): if ([myobject ismemberofclass:[nsstring class]]) { // something string specific }

17 Iden'ty versus Equality Iden'ty tes'ng equality of the pointer values if (object1 == object2) { } NSLog(@"Same exact object instance"); Equality tes'ng object abributes if ([object1 isequal: object2]) { } NSLog(@"Logically equivalent, but may be different object instances");

18 Descrip'on NSObject implements - descrip'on (NSString *)descrip'on; Objects represented in format strings using %@ When an object appears in a format string, it is asked for its descrip'on [NSString The answer is: %@, myobject]; You can log an object s descrip'on with: NSLog([anObject descrip'on]); Your custom subclasses can override descrip'on to return more specific informa'on

19 NSString General- purpose Unicode string support Unicode is a coding system which represents all of the world s languages Consistently used throughout Cocoa Touch instead of char * Without doubt the most commonly used class Easy to support any language in the world with Cocoa

20 String Constants In C constant strings are simple In ObjC, constant strings just as simple Constant strings are NSString instances NSString *astring Hello World! ;

21 Format Strings Similar to prink, but with added for objects NSString *astring Johnny ; NSString *log = [NSString It s %@, astring]; log would be set to It s Johnny Also used for logging NSLog(@ I am a %@, I have %d items, [array classname], [array count]); would log something like: I am a NSArray, I have 5 items

22 NSString Onen ask an exis'ng string for a new string with modifica'ons (NSString *)stringbyappendingstring:(nsstring *)string; (NSString *)stringbyappendingformat:(nsstring *)string; (NSString *)stringbydele'ngpathcomponent; Example: NSString *mystring Hello ; NSString *fullstring; fullstring = [mystring stringbyappendingstring:@ world! ]; fullstring would be set to Hello world!

23 NSString Common NSString methods (BOOL)isEqualToString:(NSString *)string; (BOOL)hasPrefix:(NSString *)string; (int)intvalue; (double)doublevalue; Example: NSString *mystring Hello ; NSString *otherstring 449 ; if ([mystring hasprefix:@ He ]) { // will make it here } if ([otherstring intvalue] > 500) { // won t make it here }

24 NSMutableString NSMutableString subclasses NSString Allows a string to be modified Common NSMutableString methods + (id)string; - (void)appendstring:(nsstring *)string; - (void)appendformat:(nsstring *)format,...; NSMutableString *newstring = [NSMutableString string]; [newstring appendstring:@ Hi ]; [newstring appendformat:@, my favorite number is: %d, [self favoritenumber]];

25 Collec'ons Array - ordered collec'on of objects Dic'onary - collec'on of key- value pairs Set - unordered collec'on of unique objects Common enumera'on mechanism Immutable and mutable versions Immutable collec'ons can be shared without side effect Prevents unexpected changes Mutable objects typically carry a performance overhead

26 NSArray Common NSArray methods + arraywithobjects:(id)firstobj,...; // nil terminated!!! - (unsigned)count; - (id)objectatindex:(unsigned)index; - (unsigned)indexofobject:(id)object; NSNotFound returned for index if not found NSArray *array = [NSArray arraywithobjects:@ Green, nil]; if ([array indexofobject:@ Purple ] == NSNotFound) { NSLog (@ No color purple ); } Be careful of the nil termina'on!!!

27 NSArray Examples NSArray *array; array = [NsArray one, three, nil]; int i; for (i=0; i< [array count]; i++) { NSLog (@ index %d has %a., i, [array objectatindex:i];}

28 NSArray Examples NSString *string ; NSArray *chunks = [string : ]; string = [chunks :- ) ];

29 NSMutableArray NSMutableArray subclasses NSArray So, everything in NSArray Common NSMutableArray Methods + (NSMutableArray *)array; - (void)addobject:(id)object; - (void)removeobject:(id)object; - (void)removeallobjects; - (void)insertobject:(id)object atindex:(unsigned)index; NSMutableArray *array = [NSMutableArray array]; [array addobject:@ Red ]; [array addobject:@ Green ]; [array addobject:@ Blue ]; [array removeobjectatindex:1];

30 Enumerator NSEnumator * enumerator; Enumerator = [array objectenumerator]; id thingie; while (thingie = [enumerator nextobject]) { NSLog (@ I found %a, thingie); }

31 Fast Enumera'on } for (NSString *string in array) { NSLog (@ I found %a, string);

32 NSDic'onary Common NSDic'onary methods + dic'onarywithobjectsandkeys: (id)firstobject,...; - (unsigned)count; - (id)objectforkey:(id)key; nil returned if no object found for given key NSDic'onary *colors = [NSDic'onary dic'onarywithobjectsandkeys:@ Color Color Color 3, nil]; NSString *firstcolor = [colors objectforkey:@ Color 1 ]; if ([colors objectforkey:@ Color 8 ]) { // won t make it here }

33 NSMutableDic'onary NSMutableDic'onary subclasses NSDic'onary Common NSMutableDic'onary methods + (NSMutableDic'onary *)dic'onary; - (void)setobject:(id)object forkey:(id)key; - (void)removeobjectforkey:(id)key; - (void)removeallobjects; NSMutableDic'onary *colors = [NSMutableDic'onary dic'onary]; [colors setobject:@ Orange forkey:@ HighlightColor ];

34 Another Example NSDic'onary *dict = [NSDic'onary NSMutableDic'onary *anotherdict = [NSMutableDic'onary dic'onary]; [anotherdict setobject: dict forkey: "sub- dic'onary- key"]; [anotherdict String" test"]; NSLog(@"Dic'onary: %@, Mutable Dic'onary: %@", dict, anotherdict); // now we can save these to a file NSString *savepath = [@"~/Documents/Saved.data" stringbyexpandingtildeinpath]; [anotherdict writetofile: savepath atomically: YES]; //and restore them NSMutableDic'onary *restored = [NSDic'onary dic'onarywithcontentsoffile: savepath]

35 NSSet Unordered collec'on of objects Common NSSet methods + setwithobjects:(id)firstobj,...; // nil terminated - (unsigned)count; - (BOOL)containsObject:(id)object;

36 NSMutableSet NSMutableSet subclasses NSSet Common NSMutableSet methods + (NSMutableSet *)set; - (void)addobject:(id)object; - (void)removeobject:(id)object; - (void)removeallobjects; - (void)intersectset:(nsset *)otherset; - (void)minusset:(nsset *)otherset;

37 Enumera'on Consistent way of enumera'ng over objects in collec'ons Use with NSArray, NSDic'onary, NSSet, etc. NSArray *array =... ; // assume an array of People objects // old school Person *person; int count = [array count]; for (i = 0; i < count; i++) { person = [array objectatindex:i]; NSLog([person descrip'on]); } // new school for (Person *person in array) { NSLog([person descrip'on]); }

38 NSEnumerator Example NSMutableDic'onary *mymutabledic'onary =... ; NSMutableArray *keystodeletearray = [NSMutableArray arraywithcapacity:[mymutabledic'onary count]]; NSString *akey; NSEnumerator *keyenumerator = [mymutabledic'onary keyenumerator]; while (akey = [keyenumerator nextobject]){ if ( /* test criteria for key or value */ ) { [keystodeletearray addobject:akey]; }} [mymutabledic'onary removeobjectsforkeys:keystodeletearray];

39 Fast Enumera'on for ( Type newvariable in expression ) { statements } The enumera'on is considerably more efficient than, for example, using NSEnumerator directly. The syntax is concise. Enumera'on is safe the enumerator has a muta'on guard so that if you abempt to modify the collec'on during enumera'on, an excep'on is raised.

40 Fast Enumera'on Example NSDic'onary *dic'onary = nil]; NSString *key; for (key in dic'onary) { } NSLog(@"English: %@, La'n: %@", key, [dic'onary objectforkey:key]); NSArray *array = nil]; NSEnumerator *enumerator = [array reverseobjectenumerator]; for (NSString *element in enumerator) { } if ([element isequaltostring:@"three"]) { break; } NSString *next = [enumerator nextobject];

41 Fast Enumera'on and Loop NSArray *array = /* assume this exists */; NSUInteger index = 0; for (id element in array) { } NSLog(@"Element at index %u is: %@", index, element); index++; NSArray *array = /* assume this exists */; NSUInteger index = 0; for (id element in array) { if (index!= 0) { NSLog(@"Element at index %u is: %@", index, element); } if (++index >= 6) { break; } }

42 NSNumber In Objec've- C, you typically use standard C number types NSNumber is used to wrap C number types as objects Subclass of NSValue No mutable equivalent! Common NSNumber methods + (NSNumber *)numberwithint:(int)value; + (NSNumber *)numberwithdouble:(double)value; + (NSNumber *) numberwithbool: (BOOL) value; - (int)intvalue; - (double)doublevalue; - (BOOL) boolvalue;

43 NSValue An NSValue object is a simple container for a single C or Objec've- C data item. It can hold any of the scalar types such as int, float, and char, as well as pointers, structures, and object ids. The purpose of this class is to allow items of such data types to be added to collec'ons such as instances of NSArray and NSSet, which require their elements to be objects. NSValue objects are always immutable. Constant Length

44 NSValue + (NSValue) valuewithbytes: (const void*) value objctype: (const char *) type; - (void) getvalue: (void *) value; typedef struct { float real; float imaginary; } ImaginaryNumber; ImaginaryNumber minumber, minumber2; minumber.real = 1.0; minumber.imaginary = 2.0; NSvalue *mivalue = [NSValue value: &minumber withobjctype:@encode(imaginarynumber)]; // encode using the type name [array addobject: mivalue]; value = [array objectatindex:0]; [value getvalue: &minumber2];

45 NSNull The NSNull class defines a singleton object used to represent null values in collec'on objects (which don t allow nil values). + (NSNull*) null [contact setobject: [NSNull null] home fax machine ]; id home; Homefax = [contact home fax machine ]; if (home == [NSNull null]) { } //.. No fax machine

46 Other Classes NSData / NSMutableData Arbitrary sets of bytes NSDate / NSCalendarDate Times and dates NSRange, NSPoint, NSSize, NSRect Stucture, not Object- C Object Peformance NSMakePoint(), NSMakeSize(), NSMakeRect()

47 NSDate NSDate *date =[NSDate date]; today is date]; NSDate *yesterday=[nsdate datawithtimeintervalsincenow: - (24*60*60)]; NSLog (@yesterday is %@, yesterday);

48 NSData Constant char *string = Hi There is a C string ; NSData *data=[nsdata datawithbytes: string length: strlen (string)+1]; NSLog (@ data is %@, data); NSLog (@ %d byte string is %s, [data length], [data bytes]);

49 NSData NSString *thepath NSData *mydata = [NSData datawithcontentsoffile:thepath]; unsigned char abuffer[20]; NSString *mystring string."; const char *ukstring = [mystring UTF8String]; NSData *mydata = [NSData datawithbytes: ukstring length: strlen(ukstring)]; [mydata getbytes:abuffer]; NSString *mystring const char *ukstring = [mystring UTF8String]; NSRange range = {2, 4}; NSData *data1, *data2; data1 = [NSData datawithbytes:ukstring length:strlen(ukstring)]; data2 = [data1 subdatawithrange:range]; To determine if two data objects are equal, use the isequaltodata: method, which does a byte- for- byte comparison.

50 NSFileManger The NSFileManager class enables you to perform many generic file- system opera'ons and insulates an applica'on from the underlying file system. NSFileManager *filemanager = [NSFileManager defaultmanager]; NSURL *srcurl = <#Get the source URL#>; NSURL *des'na'onurl = <#Create the des'na'on URL#>; NSError *error = nil; if (![filemanager moveitematurl:srcurl tourl:des'na'onurl error:&error]) { // Handle the error.} File Transfer Protocol (np://) Hypertext Transfer Protocol (hbp://) Secure 128- bit Hypertext Transfer Protocol (hbps://) Local file URLs (file:///)

51 #import <Founda'on/Founda'on.h> int main (int argc, const char * argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; NSFileManager *manager; manager = [NSFileManager defaultmanager]; NSString *filename; while (filename = [direnum nextobject]) { if ([[filename pathextension] { [files addobject: filename]; } } NSString *home; home = [@"~" stringbyexpandingtildeinpath]; NSDirectoryEnumerator *direnum; direnum = [manager enumeratoratpath: home]; NSMutableArray *files; files = [NSMutableArray arraywithcapacity: 42]; } NSEnumerator *fileenum; fileenum = [files objectenumerator]; while (filename = [fileenum nextobject]) { NSLog (@"%@", filename); } [pool drain]; return 0;

52 #import <Founda'on/Founda'on.h> int main (int argc, const char * argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; NSFileManager *manager; manager = [NSFileManager defaultmanager]; NSString *home; home = [@"~" stringbyexpandingtildeinpath]; NSMutableArray *files; files = [NSMutableArray arraywithcapacity: 42]; for (NSString *filename in [manager enumeratoratpath: home]) { if ([[filename pathextension] { [files addobject: filename]; } } for (NSString *filename in files) { NSLog (@"%@", filename); } } [pool drain]; return 0;

53 Homework 1 Write a program to 1) discover all the different file extensions in your computer; for each extension; 2) store all the files with that extension in a set; 3) construct a dic'onary to map each extension (key) to its corresponding set of files; 4) calculate the overall file size for each extension (number of total bytes).