動態(tài)創(chuàng)建類Class,動態(tài)添加Class成員變量與成員函數(shù),動態(tài)變量賦值與取值畔勤，動態(tài)函數(shù)調用等方法
a.使用objc_allocateClassPair創(chuàng)建一個類Class
const char * className = "Calculator";
Class kclass = objc_getClass(className);
if (!kclass)
{
Class superClass = [NSObject class];
kclass = objc_allocateClassPair(superClass, className, 0);
}
b.使用class_addIvar添加一個成員變量
NSUInteger size;
NSUInteger alignment;
NSGetSizeAndAlignment("*", &size, &alignment);
class_addIvar(kclass, "expression", size, alignment, "*");
c.使用class_addMethod添加成員方法
class_addMethod(kclass, @selector(setExpressionFormula:), (IMP)setExpressionFormula, "v@:@");
class_addMethod(kclass, @selector(getExpressionFormula), (IMP)getExpressionFormula, "@@:");
static void setExpressionFormula(id self, SEL cmd, id value)
{
NSLog(@"call setExpressionFormula");
}
static void getExpressionFormula(id self, SEL cmd)
{
NSLog(@"call getExpressionFormula");
}
注:
1.type定義參考:
2."v@:@",解釋v-返回值void類型,@-self指針id類型,:-SEL指針SEL類型,@-函數(shù)第一個參數(shù)為id類型
3."@@:",解釋@-返回值id類型,@-self指針id類型,:-SEL指針SEL類型,
d.注冊到運行時環(huán)境
objc_registerClassPair(kclass);
e.實例化類
id instance = [[kclass alloc] init];
f.給變量賦值
object_setInstanceVariable(instance, "expression", "1+1");
g.獲取變量值
void * value = NULL;
object_getInstanceVariable(instance, "expression", &value);
h.調用函數(shù)
[instance performSelector:@selector(getExpressionFormula)];
