http://blog.csdn.net/lizhongfu2013/article/details/9498233
一些公用類：
@interface CustomClass : NSObject
- (void) fun1;
@end
@implementation CustomClass
- (void) fun1
{
NSLog(@"fun1");
}
@end
@interface TestClass : NSObject
@end
@implementation TestClass
@end
別忘記引入庫：#include<objc/runtime.h>
1、對象拷貝：id object_copy(id obj, size_t size)
- (void) copyObj
{
CustomClass *obj = [CustomClassnew];
NSLog(@"%p", &obj);
id objTest = object_copy(obj,sizeof(obj));
NSLog(@"%p", &objTest);
[objTest fun1];
}
打印結果：
2013-07-26 15:35:11.547 HighOC[6859:c07] 0xbfffdf64
2013-07-26 15:35:11.547 HighOC[6859:c07] 0xbfffdf60
2013-07-26 15:35:11.547 HighOC[6859:c07] fun1
說明：
object_copy 函數實現了對象的拷貝。
2、對象釋放 id object_dispose(id obj)
- (void) objectDispose
{
CustomClass *obj = [CustomClassnew];
object_dispose(obj);
[obj release];
[obj fun1];
}
打印結果：程序crash
malloc: *** error for object 0x758e6d0: pointer being freed was not allocated
3、更改對象的類／獲取對象的類
Class object_setClass(id obj, Class cls) ／ Class object_getClass(id obj)
- (void) setClassTest
{
CustomClass *obj = [CustomClassnew];
[obj fun1];
Class aClass =object_setClass(obj, [CustomClassOtherclass]);
//obj 對象的類被更改了 swap the isa to an isa
NSLog(@"aClass:%@",NSStringFromClass(aClass));
NSLog(@"obj class:%@",NSStringFromClass([objclass]));
[obj fun2];
}
- (void) getClassTest
{
CustomClass *obj = [CustomClassnew];
Class aLogClass =object_getClass(obj);
NSLog(@"%@",NSStringFromClass(aLogClass));
}
4、獲取對象的類名 constchar *object_getClassName(id obj)
- (void) getClassName
{
CustomClass *obj = [CustomClassnew];
NSString *className = [NSStringstringWithCString:object_getClassName(obj)encoding:NSUTF8StringEncoding];
NSLog(@"className:%@", className);
}
5、給一個類添加方法
BOOL class_addMethod(Class cls,SEL name,IMP imp, const char *types)
/**
* 一個參數
*
*/
int cfunction(id self, SEL _cmd, NSString *str) {
NSLog(@"%@", str);
return10;//隨便返回個值
}
- (void) oneParam {
TestClass *instance = [[TestClassalloc]init];
// 方法添加
class_addMethod([TestClassclass],@selector(ocMethod:), (IMP)cfunction,"i@:@");
if ([instance respondsToSelector:@selector(ocMethod:)]) {
NSLog(@"Yes, instance respondsToSelector:@selector(ocMethod:)");
} else
{
NSLog(@"Sorry");
}
int a = (int)[instanceocMethod:@"我是一個OC的method，C函數實現"];
NSLog(@"a:%d", a);
}
/**
* 兩個參數
*
*/
int cfunctionA(id self, SEL _cmd, NSString *str, NSString *str1) {
NSLog(@"%@-%@", str, str1);
return20;//隨便返回個值
}
- (void) twoParam {
TestClass *instance = [[TestClassalloc]init];
class_addMethod([TestClassclass],@selector(ocMethodA::), (IMP)cfunctionA,"i@:@@");
if ([instance respondsToSelector:@selector(ocMethodA::)]) {
NSLog(@"Yes, instance respondsToSelector:@selector(ocMethodA::)");
} else
{
NSLog(@"Sorry");
}
int a = (int)[instanceocMethodA:@"我是一個OC的method，C函數實現" :@"-----我是第二個參數"];
NSLog(@"a:%d", a);
}
相關文檔及說明：
Obj-C的方法（method）就是一個至少需要兩個參數（self，_cmd）的C函數
IMP有點類似函數指針，指向具體的Method實現。
向一個類動態添加方法
BOOL class_addMethod(Class cls, SEL name, IMP imp, const char *types)
參數說明：
cls：被添加方法的類
name：可以理解爲方法名
imp：實現這個方法的函數
types：一個定義該函數返回值類型和參數類型的字符串
class_addMethod([TestClass class], @selector(ocMethod:), (IMP)testFunc, "i@:@");
其中types參數爲"i@:@“，按順序分別表示：
i：返回值類型int，若是v則表示void
@：參數id(self)
:：SEL(_cmd)
@：id(str)
一些公用類：
@interface ClassCustomClass :NSObject{
NSString *varTest1;
NSString *varTest2;
NSString *varTest3;
}
@property (nonatomic,assign)NSString *varTest1;
@property (nonatomic,assign)NSString *varTest2;
@property (nonatomic,assign)NSString *varTest3;
- (void) fun1;
@end
@implementation ClassCustomClass
@synthesize varTest1, varTest2, varTest3;
- (void) fun1 {
NSLog(@"fun1");
}
@end
@interface ClassCustomClassOther :NSObject {
int varTest2;
}
- (void) fun2;
@end
@implementation ClassCustomClassOther
- (void) fun2 {
NSLog(@"fun2");
}
@end
@interface ClassPropertyViewCtr () {
float myFloat;
ClassCustomClass *allobj;
}
myFloat = 2.34f;
6、獲取一個類的所有方法：
- (void) getClassAllMethod
{
u_int count;
Method* methods= class_copyMethodList([UIViewController class], &count);
for (int i = 0; i < count ; i++)
{
SEL name = method_getName(methods[i]);
NSString *strName = [NSString stringWithCString:sel_getName(name)encoding:NSUTF8StringEncoding];
NSLog(@"%@",strName);
}
}
打印結果（部分）：
2013-07-26 16:07:03.972 HighOC[7021:c07] _screen
2013-07-26 16:07:03.973 HighOC[7021:c07] applicationWillSuspend
2013-07-26 16:07:03.973 HighOC[7021:c07] _tryBecomeRootViewControllerInWindow:
2013-07-26 16:07:03.973 HighOC[7021:c07] isViewLoaded
2013-07-26 16:07:03.974 HighOC[7021:c07] view
......................
7、獲取一個類的所有屬性：
- (void) propertyNameList
{
u_int count;
objc_property_t *properties=class_copyPropertyList([UIViewControllerclass], &count);
for (int i = 0; i < count ; i++)
{
const char* propertyName =property_getName(properties[i]);
NSString *strName = [NSString stringWithCString:propertyNameencoding:NSUTF8StringEncoding];
NSLog(@"%@",strName);
}
}
打印結果（部分）
2013-07-26 16:09:42.182 HighOC[7041:c07] tabBarItem
2013-07-26 16:09:42.184 HighOC[7041:c07] tabBarController
2013-07-26 16:09:42.185 HighOC[7041:c07] splitViewController
2013-07-26 16:09:42.186 HighOC[7041:c07] navigationItem
2013-07-26 16:09:42.186 HighOC[7041:c07] hidesBottomBarWhenPushed
...............
8、獲取／設置類的屬性變量
//獲取全局變量的值 （myFloat 爲類的一個屬性變量）
- (void) getInstanceVar {
float myFloatValue;
object_getInstanceVariable(self,"myFloat", (void*)&myFloatValue);
NSLog(@"%f", myFloatValue);
}
//設置全局變量的值
- (void) setInstanceVar {
float newValue = 10.00f;
unsigned int addr = (unsignedint)&newValue;
object_setInstanceVariable(self,"myFloat", *(float**)addr);
NSLog(@"%f", myFloat);
}
9、判斷類的某個屬性的類型
- (void) getVarType {
ClassCustomClass *obj = [ClassCustomClassnew];
Ivar var = class_getInstanceVariable(object_getClass(obj),"varTest1");
const char* typeEncoding =ivar_getTypeEncoding(var);
NSString *stringType = [NSStringstringWithCString:typeEncodingencoding:NSUTF8StringEncoding];
if ([stringType hasPrefix:@"@"]) {
// handle class case
NSLog(@"handle class case");
} else if ([stringTypehasPrefix:@"i"]) {
// handle int case
NSLog(@"handle int case");
} else if ([stringTypehasPrefix:@"f"]) {
// handle float case
NSLog(@"handle float case");
} else
{
}
}
10、通過屬性的值來獲取其屬性的名字（反射機制）
- (NSString *)nameOfInstance:(id)instance
{
unsigned int numIvars =0;
NSString *key=nil;
//Describes the instance variables declared by a class.
Ivar * ivars = class_copyIvarList([ClassCustomClassclass], &numIvars);
for(int i = 0; i < numIvars; i++) {
Ivar thisIvar = ivars[i];
const char *type =ivar_getTypeEncoding(thisIvar);
NSString *stringType = [NSStringstringWithCString:typeencoding:NSUTF8StringEncoding];
//不是class就跳過
if (![stringType hasPrefix:@"@"]) {
continue;
}
//Reads the value of an instance variable in an object. object_getIvar這個方法中，當遇到非objective-c對象時，並直接crash
if ((object_getIvar(allobj, thisIvar) == instance)) {
// Returns the name of an instance variable.
key = [NSStringstringWithUTF8String:ivar_getName(thisIvar)];
break;
}
}
free(ivars);
return key;
}
測試代碼：
allobj = [ClassCustomClassnew];
allobj.varTest1 =@"varTest1String";
allobj.varTest2 =@"varTest2String";
allobj.varTest3 =@"varTest3String";
NSString *str = [selfnameOfInstance:@"varTest1String"];
NSLog(@"str:%@", str);
打印結果：
2013-07-26 16:26:26.271 HighOC[7081:c07] str:varTest1
11、系統類的方法實現部分替換
- (void) methodExchange {
Method m1 = class_getInstanceMethod([NSStringclass],@selector(lowercaseString));
Method m2 = class_getInstanceMethod([NSStringclass],@selector(uppercaseString));
method_exchangeImplementations(m1, m2);
NSLog(@"%@", [@"sssAAAAss"lowercaseString]);
NSLog(@"%@", [@"sssAAAAss"uppercaseString]);
}
打印結果：（仔細看log）
2013-07-26 16:33:22.776 HighOC[7104:c07] SSSAAAASS
2013-07-26 16:33:22.778 HighOC[7104:c07] sssaaaass
12、自定義類的方法實現部分替換
- (void) justLog1 {
NSLog(@"justLog1");
}
- (void) justLog2 {
NSLog(@"justLog2");
}
- (void) methodSetImplementation {
Method 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、覆蓋系統方法
IMP cFuncPointer;
IMP cFuncPointer1;
IMP cFuncPointer2;
NSString* CustomUppercaseString(idself,SEL_cmd){
printf("真正起作用的是本函數CustomUppercaseString\r\n");
NSString *string = cFuncPointer(self,_cmd);
return string;
}
NSArray* CustomComponentsSeparatedByString(idself,SEL_cmd,NSString *str){
printf("真正起作用的是本函數CustomIsEqualToString\r\n");
return cFuncPointer1(self,_cmd, str);
}
//不起作用，求解釋
bool CustomIsEqualToString(idself,SEL_cmd,NSString *str) ｛
printf("真正起作用的是本函數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,"B@:@");
}
14、自動序列化（轉）
#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;
}
用C代替OC：
#import <objc/runtime.h>
#import <objc/message.h>
#import <stdio.h>
extern int UIApplicationMain (int argc,char *argv[],void *principalClassName,void *delegateClassName);
struct Rect {
float x;
float y;
float width;
float height;
};
typedef struct Rect Rect;
void *navController;
static int numberOfRows =100;
int tableView_numberOfRowsInSection(void *receiver,structobjc_selector *selector, void *tblview,int section) {
returnnumberOfRows;
}
void *tableView_cellForRowAtIndexPath(void *receiver,structobjc_selector *selector, void *tblview,void *indexPath) {
Class TableViewCell = (Class)objc_getClass("UITableViewCell");
void *cell = class_createInstance(TableViewCell,0);
objc_msgSend(cell, sel_registerName("init"));
char buffer[7];
int row = (int) objc_msgSend(indexPath, sel_registerName("row"));
sprintf (buffer, "Row %d", row);
void *label =objc_msgSend(objc_getClass("NSString"),sel_registerName("stringWithUTF8String:"),buffer);
objc_msgSend(cell, sel_registerName("setText:"),label);
return cell;
}
void tableView_didSelectRowAtIndexPath(void *receiver,structobjc_selector *selector, void *tblview,void *indexPath) {
Class ViewController = (Class)objc_getClass("UIViewController");
void * vc = class_createInstance(ViewController,0);
objc_msgSend(vc, sel_registerName("init"));
char buffer[8];
int row = (int) objc_msgSend(indexPath, sel_registerName("row"));
sprintf (buffer, "Item %d", row);
void *label =objc_msgSend(objc_getClass("NSString"),sel_registerName("stringWithUTF8String:"),buffer);
objc_msgSend(vc, sel_registerName("setTitle:"),label);
objc_msgSend(navController,sel_registerName("pushViewController:animated:"),vc,1);
}
void *createDataSource() {
Class superclass = (Class)objc_getClass("NSObject");
Class DataSource = objc_allocateClassPair(superclass,"DataSource",0);
class_addMethod(DataSource,sel_registerName("tableView:numberOfRowsInSection:"), (void(*))tableView_numberOfRowsInSection,nil);
class_addMethod(DataSource,sel_registerName("tableView:cellForRowAtIndexPath:"), (void(*))tableView_cellForRowAtIndexPath,nil);
objc_registerClassPair(DataSource);
returnclass_createInstance(DataSource,0);
}
void * createDelegate() {
Class superclass = (Class)objc_getClass("NSObject");
Class DataSource = objc_allocateClassPair(superclass,"Delegate",0);
class_addMethod(DataSource,sel_registerName("tableView:didSelectRowAtIndexPath:"), (void(*))tableView_didSelectRowAtIndexPath,nil);
objc_registerClassPair(DataSource);
returnclass_createInstance(DataSource,0);
}
void applicationdidFinishLaunching(void *receiver,structobjc_selector *selector, void *application) {
Class windowClass = (Class)objc_getClass("UIWindow");
void * windowInstance = class_createInstance(windowClass, 0);
objc_msgSend(windowInstance, sel_registerName("initWithFrame:"),(Rect){0,0,320,480});
//Make Key and Visiable
objc_msgSend(windowInstance,sel_registerName("makeKeyAndVisible"));
//Create Table View
Class TableViewController = (Class)objc_getClass("UITableViewController");
void *tableViewController = class_createInstance(TableViewController, 0);
objc_msgSend(tableViewController, sel_registerName("init"));
void *tableView = objc_msgSend(tableViewController,sel_registerName("tableView"));
objc_msgSend(tableView, sel_registerName("setDataSource:"),createDataSource());
objc_msgSend(tableView, sel_registerName("setDelegate:"),createDelegate());
Class NavController = (Class)objc_getClass("UINavigationController");
navController = class_createInstance(NavController,0);
objc_msgSend(navController,sel_registerName("initWithRootViewController:"),tableViewController);
void *view =objc_msgSend(navController,sel_registerName("view"));
//Add Table View To Window
objc_msgSend(windowInstance, sel_registerName("addSubview:"),view);
}
//Create an class named "AppDelegate", and return it's name as an instance of class NSString
void *createAppDelegate() {
Class mySubclass = objc_allocateClassPair((Class)objc_getClass("NSObject"),"AppDelegate",0);
structobjc_selector *selName =sel_registerName("application:didFinishLaunchingWithOptions:");
class_addMethod(mySubclass, selName, (void(*))applicationdidFinishLaunching,nil);
objc_registerClassPair(mySubclass);
returnobjc_msgSend(objc_getClass("NSString"),sel_registerName("stringWithUTF8String:"),"AppDelegate");
}
int main(int argc, char *argv[]) {
returnUIApplicationMain(argc, argv,0,createAppDelegate());
}
運行效果：
