1. 发送消息
objc_msgSend(obj, @selector(func)); 调用实例方法
objc_msgSend([Obj class], @selector(func)); 调用类方法
2.交换方法
// 加载内存时调用
+ (void)load
{
// 获取 ImageOriginalWithStrName: 方法
MethodmyImageName =class_getClassMethod(self,@selector(myImageNamed:));
// 获取 imageName 方法
MethodimageName =class_getClassMethod(self,@selector(imageNamed:));
// 交换方法地址, 相当于交换实现
method_exchangeImplementations(myImageName, imageName);
}
+ (id)myImageNamed:(NSString*)name
{
UIImage *image = [[self myImageName:name] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
if(image ==nil) {
NSLog(@"我自己的操作");
}
returnimage;
}
3.动态添加方法
[self performSelector:@selector(test)];
void test (id self, SEL sel){
NSLog(@"--- ");
}
/*
当一个对象调用未实现的方法,会调用+ (BOOL)resolveInstanceMethod:(SEL)sel
这个方法处理,并且会把这个对应方法列表传过来
所以动态添加方法, 我们可以在这里做判断, 为我们未实现的方法动态添加自己的方法.
*/
+(BOOL)resolveInstanceMethod:(SEL)sel{
if (sel == NSSelectorFromString(@"test1")) {
// <#__unsafe_unretained Class cls#> 参数1 给哪个类添加方法
// <#SEL name#> 参数2 添加哪个方法
// <#IMP imp#> 参数3 添加方法函数实现 (函数地址)
// <#const char *types#> 参数4 函数的类型 (返回值 + 参数类型) v:void @:对象-> self :表示SEL -> _cmd
class_addMethod(self, sel, (IMP)test1, "v@:@");
return YES;
}
return [super resolveInstanceMethod:sel];
}
4.给分类添加属性
@interface NSObject (ObjName)
@property (nonatomic, strong) NSString *name; // 添加一个name属性
@end
#import
static const char *key = "name";
@implementation NSObject (ObjName)
- (NSString *)name{
// 根据关联的key,获取关联的值
return objc_getAssociatedObject(self, key);
}
- (void)setName:(NSString *)name{
// 参数1 id object 给那个对象添加关联
// 参数2 const void *key 关联的key 值,通过这个key 值获取
// 参数3 id value 关联的value
// 参数4 objc_AssociationPolicy policy 关联的策略
objc_setAssociatedObject(self, key, name, OBJC_ASSOCIATION_COPY_NONATOMIC);
}
@end
5.模型转换
- (instancetype)initWithDict:(NSDictionary *)dict
{
self = [super init];
if (self)
{
// 获取类的属性及属性对应的类型
NSMutableArray *keys = [NSMutableArray array];
unsigned int outCount;
objc_property_t *properties = class_copyPropertyList([self class], &outCount);
for (int i = 0; i < outCount; i ++)
{
objc_property_t property = properties[i];
// 通过property_getName函数获得属性的名字
NSString *propertyName = [NSStringstringWithCString:property_getName(property) encoding:NSUTF8StringEncoding];
[keys addObject:propertyName];
}
// 立即释放properties指向的内存
free(properties);
// 根据类型给属性赋值
NSLog(@"+++%@",keys);
for (NSString *key in keys)
{
id value = [dict valueForKey:key];
if (value == nil)
{
continue;
}
[self setValue:value forKey:key];
}
}
return self;
}
6.归档、解档
//归档- (void)encodeWithCoder:(NSCoder*)aCoder
{ unsigned int count = 0;
Ivar* ivars = class_copyIvarList([self class], &count);
for (int i = 0; i < count; i++) { Ivar ivar = ivars[i]； const char* name = ivar_getName(ivar); NSString* key = [NSString stringWithUTF8String:name];
[aCoder encodeObject:[self valueForKey:key] forKey :key];
}
free(ivars);
}//解档- (id)initWithCoder:(NSCoder*)aDecoder
{ if (self == [superinit]) { unsigned int count = 0; Ivar* ivars = class_copyIvarList([selfclass], &count); for (int i = 0; i < count; i++) { Ivar ivar = ivars[i]; const char* name = ivar_getName(ivar); NSString* key = [NSStringstringWithUTF8String:name]; id value = [aDecoder decodeObjectForKey:key];//根据key拿到value [self setValue:value forKey:key];//KVC赋值 } free(ivars); }return self;
}