背景:目前iOS工程較多將json數據轉換成一個對象來儲存。假設這個對象有一個Attributes為NSString類型叫myName,這個Attributes一直是nil,創建這對象後忘記對它賦值。現在要通過一個函數來檢測他出來,再將他賦值為@“”;
另外,我不知道有多少個Attributes,只要是NSString類型而且Attributes是nil就賦值為@“”。
代碼如下:
//
// GMCommonHelper.h
#import
#import
@interface GMCommonHelper : NSObject
+(void)fixNilData:(id)kClass;
@end
//
// GMCommonHelper.m
#import
#import “GMCommonHelper.h"
@implementation GMCommonHelper
+(void)fixNilData:(id)kClass
{
unsigned int propertyCount = 0;
objc_property_t *properties = class_copyPropertyList([kClass class], &propertyCount);
for (unsigned int i = 0; i < propertyCount; ++i) {
objc_property_t property = properties[i];
const char * name = property_getName(property);
const char * attrs = property_getAttributes(property);
NSString * utf8Name = [NSString stringWithUTF8String:name];
NSString * utf8Attrs = [NSString stringWithUTF8String:attrs];
id propertVal = [kClass valueForKey:utf8Name];
if (!propertVal && [utf8Attrs hasPrefix:@"T@\"NSString\""]) {
[kClass setValue:@"" forKey:utf8Name];
}
}
free(properties);
}
//———————————————————————
-
(void)releaseProperties { unsigned int c = 0; objc_property_t *properties = class_copyPropertyList([self class], &c); for(unsigned int i = 0; i < c; i++) { objc_property_t property = properties[i]; NSString *propertyName = [NSString stringWithUTF8String:property_getName(property)];
NSString *propertyType = [NSString stringWithUTF8String:property_getAttributes(property)]; if([propertyType hasPrefix:@"T@"] // is an object && [propertyType rangeOfString:@",R,"].location == NSNotFound // not readonly ) { [self setValue:nil forKey:propertyName];
NSLog(@"%@.%@ = %@", NSStringFromClass(cls), propertyName, [self valueForKey:propertyName]); } } free(properties);}
//———————————————————————
If you only care about classes you can use isKindOfClass:
,
but if you want to deal with scalars you are correct that you need to use property_getAttributes()
,
it returns a string that encodes the type information. Below is a basic function that demonstrates what you need to do. For examples of encoding strings, look here.
unsigned int outCount, i;
objc_property_t *properties = class_copyPropertyList([object class], &outCount);
for (i = 0; i < outCount; i++) {
objc_property_t property = properties[i];
char *property_name = property_getName(property);
char *property_type = property_getAttributes(property);
switch(property_type[1]) {
case 'f' : //float
break;
case 's' : //short
break;
case '@' : //ObjC object
//Handle different clases in here
break;
}
}
Obvviously you will need to add all the types and classes you need to handle to this, it uses the normal ObjC @encode type。