Thoughts on studying objective-c in winter vacation

Bought this "learn Objective-c on Mac", a start to buy looks very thin, 250 pages, after reading, found that the language has a lot of common place, the new features are from C + + and Java similar to come over, is changed a name, feel after seeing the harvest pretty big, Although only touched a little fur.

1.C language knowledge

2. Learn about Xcode's use of

3. Understand some new grammar and new features.

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1. Formal agreement and informal agreement (replaced by @optional formal agreement) and file loading save

@required must be realized

@optional Selective implementation

Example 1.

@protocol nscopying//Deep copy replication

-(ID) Copywithzone: (nszone*) zone;

@end

Copy of Nsarray is shallow copy

@protocol nscoding//encoding and decoding

-(void) Encodewithcoder: (nscoder*) Acoder;

-(ID) Initwithcoder: (nscoder*) decoder;

Nscoding can be used to encode any object as NSData nsdata available [data writetofile: "Tmp.txt" atomically:true] to the hard disk

Example 1:

@interface a:nsobject<nscopying,nscoding> {nsstring*name;} @property (copy) Nsstring*name; @end @implementation A @synthesize name; -(ID) Copywithzone: (nszone*) zone {A *a; a=[[[self class]allocwithzone:zone]init]; a.name=self.name; return A;}-(void) Encodewithcoder: (nscoder*) Acoder {[Acoder codewithobject:name forkey:@ ' name '];}-(ID) Initwithcoder: (NSCoder*) Decoder {if (self=[super init]) {nsstring*n=[decoder decodeobjectforkey:@ "name"];} return self;}

Encoded as NSData by the Nskeyedarchiver class

Nsdata*data=[nskeyedarchiver Archiveddatawithrootobject: Object]; Automatic Call Encodewithcoder

A *a=[nskeyedunarchiver Unarchiveobjectwithdata:data]; Decoding

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Property list Nsarray nsdictionary nsstring nsnumber nsdate nsdata

1.NSArray

+ (ID) Arraywithobject: ... End With Nil

-(unsigned) count;

-(ID) Objectatindex: (unsigned) index;

Nsmutablearray

+ (ID) arraywithcapacity: (int);

-(void) AddObject: (NSObject);

-(void) Removeobjectatindex: (int) index;

2.NSDictionary

+ (ID) Dicitonarywithobjectsandkeys: (ID) firstobject, (nsstring*) Firstkey ...;

-(ID) Objectforkey: (ID) key;

Nsmutabledictionary

+ (ID) dicitonarywithcapacity: (int) n;

-(void) SetObject: (ID) object forkey: (ID) key;

-(void) Removeobjectforkey: (ID) key;

3.NSNumber

Package standard Type

Nsnumber*a=[nsnumber Numberwithint:10];

4.NSDate

+ (nsdate*) date;

+ (nsdate*) Datewithtimeintervalsincenow: (int) A;

5.NSData

+ (nsdata*) Datawithbytes: (nsobject) Length: (int);

-(int) length;

-(nsobject) bytes;

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Predicate:

Predicates are actually a simple way to give a constraint that can be substituted for and if

Nspredicate:

+ (nspredicate) Predicatewithformat: ....

-(nsarray*) filteredarrayusingpredicate:predicate;

Example: @interface a:nsobject {nsstring*name;} @property nsstring*name; @end @implementation A @synthesize name; @end @interface B; NSObject {nsmutablearray*a;} @end @implementation B-(void) AddA (nsstring*n) {a*object; object.name=n; A.add (object);} @end int main () {b* bobject=[[b alloc]init]; Bobject.adda ("A"); Bobject.adda ("B"); Bobject.adda ("C"); Bobject.adda ("D") ; Nspredicate*predicate=[nspredicate predicatewithformat:@ "name=%@", "A"]; Nsarray*result=[bobject Filteredarrayusingpredicate:predicate]; }

Predicates are also given a number of operators (operators that can inherit C)

Example: A class that inherits an example

Nspredicate*predicate=[nspredicate predicatewithformat:@ "(name== ' A ') and (name== ' B ')"];

Array operator name Between{min,max};

Name in{"A", "B"};

The use of self:

Nsarray*a=[nsarray arraywithobject:@ "A", "B", nil];

Nspredicate*predicate=[nspredicate Predicatewithformat: @SELF in "' A ', ' B '"];

nsarray* B=[a Filteredarrayusingpredicate:predicate];

String operators:

Beginswith

ENDSWITH

CONTAINS

[C] Ignore case

[d] Ignore accent

[CD] is ignored

Example: Beginswith[c]

Like operator

A can be included in the middle of like ' *a* '

Like '?? A * ' preceded by two characters