gioi thieu ve objective-c(tiếng việt)

5/26/2018 Gioi Thieu Ve Objective-C(Ti ng Vi t)

1/28

L

!p trnh

"ng d

#ng trn iOS

Objective-C


2/28

N$i dung Gi!i thi"u v#Objective-C Quy t$c !%t tn l!p, tn ph&'ng th(c, tn bi)n Class trong Objective-C Ph*m vi truy xu+t cc bi)n th,hi"n

Property trong Objective-C Ph&'ng th(c trong Objective-C Category trong Objective-C Protocol trong Objective-C K)th-a X.l"ngo*i l" M/t s0c+u trc !i#u khi,n trong Objective-C Qu1n l"b/nh! Selector trong Objective-C


3/28

Gi%i thi&u v'Objective-C

Ngn ng2l3p trnh h&!ng !0i t&4ng ANSI C + Smalltalk = Objective-C Objective-C l ngn ng2l3p trnh chnh!&4c Apple ch5n !,vi)t cc (ng d6ng

cho h"!i#u hnh Mac OS, iOS

--> D7dng n$m b$t !&4c ngn ng2Objective-C n)u c kinh nghi"m v#C


4/28

Quy t(c )*t tn

Class B$t !8u b9ng k"t:hoa

Method B$t !8u b9ng k"t:th&;ng

Variable

Gi0ng method

@interface MyClass : NSObject{}

@end

- (void) findMe;

NSString *stringURL;

MyClass.h@interface MyClass : NSObject{

NSString *stringURL;}

- (void) findMe;

@end


5/28

Class trong Objective-C

@interface: Khai bo class @implementation: #


6/28

Ph+m vi truy xu,t cc bi-n

@private: Gi!i h*n ph*m vi trong l!p mbi)n th,hi"n !&4c khai bo

@protected (default): Gi

!i h*n ph

*m vitrong l!p v l!p con k)th-a m bi)n th,

hi"n !&4c khai bo @public: Khng gi!i h*n ph*m vi truy

xu+t


7/28

Ph+m vi truy xu,t cc bi-n (tt)

V d6:


8/28

Property trong Objective-C

Property cho php ! Thu3n l4

i cho vi"c truy xu

+t !

)n ccbi)n th,hi"n

#


9/28

Property trong Objective-C (tt)

Cc thu/c tnh (attributes) readwrite(default): !5c v ghi (get/set) read-only: ch=c th,!5c (get) assign (default): Th&;ng dng v!i cc ki,u

v h&!ng nh&NSInteger, CGFloat, CGrect, retain: Th&;ng !&4c s.d6ng cho !0i t&4ng copy: T*o m/t b1n sao c>a !0i t&4ng s?!&4c s.d6ng cho !0i t&4ng ch=!


10/28


Cc thu/c tnh (attributes)-atomic// @property (retain)UITextField *username;

// Generates roughly- (UITextField *) username{

UITextField *retval = nil;

@synchronized(self) {retval = [[username retain] autorelease];

}returnretval;

}- (void)setUsername: (UITextField *)_username {@synchronized(self) {

[_username retain];[username release];

username = _username;

}}


11/28


Cc thu/c tnh (attributes)-nonatomic// @property (retain,nonatomic)UITextField *username;

// Generates roughly

- (UITextField *) username{returnusername;

}- (void)setUsername: (UITextField *)_username {

[_username retain];[username release];

username = _username;

}


12/28

Ph./ng th"c trong Objective-C

Class method K"hi"u d+u + Truy xu+t thng qua tn l!p Khng th,truy c3p vo cc bi)n th,hi"n

(Instance variables) Instance method

K"hi"u d+u - Truy xu+t thng qua !0i t&4ng


13/28

Ph./ng th"c trong Objective-C (tt)

Khai bo ph&'ng th(c:-/+ (return_type) method;-/+ (return_type) methodPara1 : (type) para1;-/+ (return_type) methodPara1 : (type) para1 andPara2: (type) para2;

G5i ph&'ng th(c:// Class methodMyClass *myClass = [MyClass method];

// Instance method[object method];[object methodPara1:pa1];[object methodPara1:pa1 andPara2:pa2];


14/28

Category trong Objective-C

Khi mu0n thm m/t s0ph&'ng th(c vom/t l!p c sAn MBr/ng l!p ! b9ng cch vi)t l*i m ngu@n MBr/ng l!p ! khng c8n vi)t l*i m ngu@n

--> CategoryMyClass.h

@interface MyClass : NSObject{

}- (void) showMe;

@end

MyClass.m@implementation MyClass

- (void) showMe {// show me

}@end


15/28

Category trong Objective-C (tt)

Thm m/t ph&'ng th(c newMethod chol!p MyClass thng qua CategoryMyClass+MyCategory.h

@interface MyClass (MyCategory)- (void) newMethod;

@end

MyClass+MyCategory.m@implementation MyClass (MyCategory)

- (void) newMethod {// to do new method

}@end

Ch !: - Tn c0a Category l duy nh,t (Khng ".1c trng)

- Trong Category khng cho php thm cc bi2n th2hi&n


16/28

Procol trong Objective-C

Protocol l g ? V d6:

@protocol MyProtocol// required (default)

- (void) requiredMethod;

@optional- (void) anOptionalMethod;

- (void) anotherOptionalMethod;

@required

- (void) anotherRequiredMethod;

@end


17/28

K-th3a

T&'ng t:nh&cc ngn ng2khc Trong Objective-C, root class c>a t+t c1

cc class l NSObject

Person.h@interface Person:NSObject {

NSString*name;NSString*birthday;

}//

@end

Teacher.h@interface Teacher:Person{

floatfSalary;}

// @end

Person

Teacher


18/28

X4lngo+i l&


19/28

M$t s5c,u trc i'u khi2n

If For

Switch While


20/28

Qu6n lb$nh%

Cc nguyn t$c qu1n l"b/nh! V+n !#khi khBi t*o !0i t&4ng

Release Retain Dealloc Tham chi)u y)u


21/28

Qu6n lb$nh% Cc nguyn t$c qu1n l"b/nh! Nguyn t$c c%n b1n

Khi b*n n$m quy#n sBh2u m/t !0i t&4ng, khBi t*o !0i t&4ng b9ngcc ph&'ng th(c m trong tn b$t !8u v!i v!i alloc ho%c new ho%ccopy (v d6, alloc, newObject ho%c mutableCopy) ho%c g.i m/tthng !i"p retain, b*n ph1i c trch nhi"m gi1i phng quy#n sBh2u!0i t&4ng ! b9ng cch s.d6ng release ho%c autorelease. B+t k&

khi no b*n nh3n !&4c m/t !0i t&4ng (khng ph1i t:mnh khBi t*o),b*n khng !&4c release n. Nguyn t$c khc

Khi b*n c8n l&u tr2m/t !0i t&4ng !&4c nh3n nh&m/t propertytrong m/t bi)n th,hi"n, b*n ph1i retain ho%c copy n. (#i#u nykhng !ng cho cho tham kh1o y)u, nh&ng !y l !i,n hnh hi)m).

M/t !0i t&4ng !&4c nh3n th&;ng !1m b1o vCn c hi"u l:c trongph&'ng th(c m n ! !&4c nh3n (ngo*i tr-trong cc (ng !a lu@ngv vi tr&;ng h4p Distributes Objects). Ph&'ng th(c ! c th,tr1v#an ton !0i t&4ng m n !&4c tri"u g5i. S.d6ng retain trongvi"c k)t h4p v!i release ho%c autorelease khi c8n thi)t !,b1o v"m/t !0i t&4ng khDi hi"u l:c c>a cc thng !i"p khng h4p l"bnngoi.

autorelease c ngh$a l g.i m/t thng !i"p release sau !


22/28

Qu6n lb$nh%

V+n !#khi khBi t*o !0i t&4ngMyClass *myClass = [MyClass alloc];

[myClass init];if(myClass) {

//

}

???


23/28

Qu6n lb$nh%

V+n !#khi khBi t*o !0i t&4ng (tt)MyClass *myClass = [[MyClass alloc] init];

if(myClass) {//

}

OK

Ch !: - Lun lun tr6v'niltrong ph./ng th"c initn-u c l7i x6y ra- Ph6i k-t h1p 02 l8i g9i ph./ng th"c allocv init


24/28

Qu6n lb$nh%

Release Ch=!&4c releasekhi khBi t*o !0i t&4ng

m/t cch th>cng alloc KHNG releaseth>cng m/t !0i t&4ng

autorelease--> CRASH

// string2 will be released automaticallyNSString*string2 = [NSStringstring];

// Must release string1 when doneNSString*string1 = [[NSStringalloc] init];

// [string1 release];

!"#$%&'&()&

%&'&()&


25/28

Qu6n lb$nh%

Retain MEi !0i t&4ng c m/t b/!)m !&4c s.d6ng !,ki,m

sot t+t c1cc tham chi)u bBi !0i t&4ng ho%c n c Ph&'ng th(c alloc, new, copy v retain !#u lm t%ngb/!)m ln 1 Ph&'ng th(c release gi1m b/!)m !i 1 Khi b/!)m c gi tr Ph&'ng th(c dealloc

c>a !0i t&4ng s?!&4c g5i#,xc !


26/28

Qu6n lb$nh%

Dealloc#&4c g5i khi !0i t&4ng !ang !&4c remove

khDi b/nh! N)u m/t l!p c cc bi)n th,hi"n (instance

variable) l cc !0i t&4ng th trong ph&'ngth(c dealloc c>a l!p ph1i th:c hi"n gi1ii

phng cc bi)n th

,hi"n ny- (void) dealloc {

[childVar1 release];

[childVar2 release];//

[superdealloc];

}


27/28

Qu6n lb$nh%

Tham chi)u y)u T*o tham chi)u !)n !0i t&4ng m khng c1n

trB!0i t&4ng t:gi1i phng chnh n -->

Thi)t l3p tham chi)u y)u !)n !0i t&4ng


28/28

Selector trong Objective-C

Selector trong Objective-C c 02 "ngh$a: Ch=!)n tn c>a m/t ph&'ng th(c khi n!&4c s.d6ng trong m ngu@n m/t thng!i"p gBi !)n m/t !0i t&4ng

Ch=!)n m/t !

gioi thieu ve objective-c(tiếng việt)

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