iOS advanced development, Runtime (iii)

11, the System class method realizes partial substitution

-(void) Methodexchange {

Method m1 = Class_getinstancemethod ([NSString class], @selector (lowercasestring));

Method m2 = Class_getinstancemethod ([NSString class], @selector (uppercasestring));

Method_exchangeimplementations (M1, M2);

NSLog (@ "%@", [@ "AAAAAAAA" lowercasestring]);

NSLog (@ "%@", [@ "AAAAAAAA" uppercasestring]);

}

Operation Result:

2014-10-20 14:48:17.584 runtimetest[14921:303] Aaaaaaaa

2014-10-20 14:48:17.586 runtimetest[14921:303] Aaaaaaaa

12. Partial substitution of the method implementation of the custom class

-(void) JustLog1 {

NSLog(@ "JustLog1");

}

-(void) justLog2 {

NSLog(@ "justLog2");

}

-(void) methodsetimplementation {

Method = Class_getinstancemethod([classmethodviewctrclass],@selector(JUSTLOG1) );

IMP originalimp = method_getimplementation (method);

Method m1 = Class_getinstancemethod([classmethodviewctrclass],@selector( JUSTLOG2));

Method_setimplementation(M1, originalimp);

}

[Self methodsetimplementation];

[Self justLog2];

13. Coverage System method

IMP Cfuncpointer;

IMP CFuncPointer1;

IMP CFuncPointer2;

nsstring* customuppercasestring (ID self,SEL_cmd) {

printf(" What really works is this function customuppercasestring\r\n");

nsstring *string = cfuncpointer (self,_cmd);

return string;

}

nsarray* customcomponentsseparatedbystring (ID self,SEL_cmd,nsstring *str) {

printf(" What really works is this function customisequaltostring\r\n");

return cFuncPointer1 (self,_cmd, str);

}

does not work, to explain

BOOL Customisequaltostring (ID self,SEL_cmd,nsstring *str) {

printf(" What really works is this function customisequaltostring\r\n");

return cFuncPointer2 (self,_cmd, str);

}

-(void) replacemethod{

cfuncpointer = [NSStringinstancemethodforselector:@selector(uppercasestring)];

Class_replacemethod ([NSStringclass],@selector (uppercasestring), (IMP) Customuppercasestring,"@@:");

cFuncPointer1 = [nsstringinstancemethodforselector:@selector (componentsseparatedbystring:)];

Class_replacemethod ([NSStringclass],@selector (componentsseparatedbystring:), (IMP) Customcomponentsseparatedbystring,"@@:@");

cFuncPointer2 = [NSStringinstancemethodforselector:@selector(isequaltostring:)];

Class_replacemethod ([NSStringclass],@selector (isequaltostring:), (IMP) Customisequaltostring,"[email protected]:@");

}

14. automatic serialization (GO)

#import "Nsobject+autoencodedecode.h"

@implementation NSObject (Autoencodedecode)

-(void) Encodewithcoder: (nscoder *) Encoder {

class CLS = [selfClass];

While (cls! = [nsobjectclass]) {

unsigned int numberofivars =0;

ivar* ivars = class_copyivarlist (CLS, &numberofivars);

For (const ivar* p = ivars; p < ivars+numberofivars; p++) {

Ivar Const IVAR = *p;

const Char *type =ivar_gettypeencoding (Ivar);

NSString *key = [NSStringstringwithutf8string: Ivar_getname(Ivar)];

id value = [selfvalueforkey:key];

if (value) {

switch (type[0]) {

Case _c_struct_b: {

Nsuinteger ivarsize =0;

Nsuinteger ivaralignment =0;

nsgetsizeandalignment (Type, &ivarsize, &ivaralignment);

NSData *data = [nsdatadatawithbytes: (constchar *) Self+ Ivar_getoffset (Ivar)

Length:ivarsize];

[Encoder Encodeobject:dataForkey:key];

}

Break ;

Default:

[Encoder Encodeobject:value

Forkey:key];

Break ;

}

}

}

Free (ivars);

CLS = Class_getsuperclass (CLS);

}

}

-(ID) Initwithcoder: (nscoder *) Decoder {

Self = [self init];

if (self) {

class CLS = [selfClass];

While (cls! = [nsobjectclass]) {

unsigned int numberofivars =0;

ivar* ivars = class_copyivarlist (CLS, &numberofivars);

For (constivar* p = ivars; p < ivars+numberofivars; p++) {

Ivar Const IVAR = *p;

const Char *type =ivar_gettypeencoding (Ivar);

NSString *key = [NSStringstringwithutf8string: Ivar_getname(Ivar)];

id value = [decoder decodeobjectforkey:key];

if (value) {

switch (type[0]) {

Case _c_struct_b: {

Nsuinteger ivarsize =0;

Nsuinteger ivaralignment =0;

nsgetsizeandalignment (Type, &ivarsize, &ivaralignment);

NSData *data = [decoderdecodeobjectforkey:key];

char *sourceivarlocation = (char*)self+Ivar_getoffset (Ivar);

[Data getbytes:sourceivarlocationlength:ivarsize];

}

Break ;

Default:

[self setvalue:[decoder Decodeobjectforkey:key]

Forkey:key];

Break ;

}

}

}

Free (ivars);

CLS = Class_getsuperclass (CLS);

}

}

return self;

}

iOS advanced development, Runtime (iii)