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起因:做网络交互时,经常会使用JSON作为数据的承载体,本来是件好事,但是用多了,发现iOS侧偶尔会出现异常,几经比较发现是服务器给的数据有问题,该给INT的给按照STR给了,
服务器能做动态更新,可客户端不行啊,怎么办?NSDictionary读到的是id类型,如果是数字,需要再转换下才可以,出问题就在这里.那解决思路就在这里,在这里增加判断
实现
用到了以下几个知识点
@encode()
为了更好的互操作性，Objective-C 的数据类型，甚至自定义类型、函数或方法的元类型，都可以使用 ASCII 编码。@encode(aType) 可以返回该类型的 C 字符串（char *）的表示
[obj objcType]
获取obj对象的对象类型的C编码字符串.
OK,比较就好.
#import <Foundation/Foundation.h> /* 改造 1 增加读取数据时,如果没有键值,返回默认值的动作. 2 屏蔽无键值时字典异常的问题. 3 增加双字段类型CGPoint的读取动作. 4 增加底层判断实际数据类型与读取动作不匹配导致的问题. */ @interface NSDictionary (ReadAdditions) - (BOOL)getBoolValueForKey:(NSString *)key defaultValue:(BOOL)defaultValue; - (NSInteger)getIntValueForKey:(NSString *)key defaultValue:(NSInteger)defaultValue; - (float)getFloatValueForKey:(NSString *)key defaultValue:(float)defaultValue; - (time_t)getTimeValueForKey:(NSString *)key defaultValue:(time_t)defaultValue; - (long long)getLongLongValueValueForKey:(NSString *)key defaultValue:(long long)defaultValue; - (NSString *)getStringValueForKey:(NSString *)key defaultValue:(NSString *)defaultValue; - (id)getValueForKey:(NSString*)key defaultValue:(id)defalueValue; - (CGPoint)getPointForKey:(NSString*)xKey yKey:(NSString*)yKey defaultValue:(CGPoint)defaultValue; @end
实现
#import "NSDictionaryReadAdditions.h"
typedef NS_ENUM(NSUInteger, PODTYPE)
{
PT_UNKNOWN = -1,
PT_INT = 0,
PT_FLOAT,
PT_DOUBLE,
PT_BOOL,
PT_INT64,
PT_STRING,
PT_ARRAY,
};
@implementation NSDictionary (ReadAdditions)
-(PODTYPE)getPodType:(id)obj
{
if([obj isKindOfClass:[NSNumber class]])
{
const char * pObjCType = [((NSNumber*)obj) objCType];
if (strcmp(pObjCType, @encode(BOOL)) == 0)
{
return PT_BOOL;
}
if (strcmp(pObjCType, @encode(int)) == 0)
{
return PT_INT;
}
if (strcmp(pObjCType, @encode(float)) == 0)
{
return PT_FLOAT;
}
if (strcmp(pObjCType, @encode(double)) == 0)
{
return PT_DOUBLE;
}
}
return PT_UNKNOWN;
}
-(BOOL)isPodIntObj:(id)obj
{
if (nil == obj)
return NO;
if([obj isKindOfClass:[NSNumber class]])
{
const char * pObjCType = [((NSNumber*)obj) objCType];
if (strcmp(pObjCType, @encode(int)) == 0)
{
return YES;
}
}
return NO;
}
-(BOOL)isPodBoolObj:(id)obj
{
if (nil == obj)
return NO;
if([obj isKindOfClass:[NSNumber class]])
{
const char * pObjCType = [((NSNumber*)obj) objCType];
if (strcmp(pObjCType, @encode(BOOL)) == 0)
{
return YES;
}
}
return NO;
}
-(BOOL)isPodFloatObj:(id)obj
{
if (nil == obj)
return NO;
if([obj isKindOfClass:[NSNumber class]])
{
const char * pObjCType = [((NSNumber*)obj) objCType];
if (strcmp(pObjCType, @encode(float)) == 0)
{
return YES;
}
}
return NO;
}
-(BOOL)isPodInt64Obj:(id)obj
{
if (nil == obj)
return NO;
if([obj isKindOfClass:[NSNumber class]])
{
const char * pObjCType = [((NSNumber*)obj) objCType];
if (strcmp(pObjCType, @encode(long long)) == 0)
{
return YES;
}
}
return NO;
}
-(BOOL)isNSTypeObj:(id)obj andType:(Class)objClass
{
if (nil == obj || nil == objClass)
return NO;
if ([obj isMemberOfClass:objClass])
{
return YES;
}
return NO;
}
- (BOOL)getBoolValueForKey:(NSString *)key defaultValue:(BOOL)defaultValue {
id obj = [self getValueForKey:key defaultValue:nil];
if (nil == obj)
{
return defaultValue;
}
if ([self isPodBoolObj:obj])
return [obj boolValue];
else
{
NSLog(@"警告[%s],数据对象类型不符:%@",__FUNCTION__, key);
}
return defaultValue;
}
- (NSInteger)getIntValueForKey:(NSString *)key defaultValue:(NSInteger)defaultValue {
id obj = [self getValueForKey:key defaultValue:nil];
if (nil == obj)
{
return defaultValue;
}
if ([self isPodIntObj:obj])
return [obj integerValue];
else
{
NSLog(@"警告[%s],数据对象类型不符:%@",__FUNCTION__, key);
}
return defaultValue;
}
- (float)getFloatValueForKey:(NSString *)key defaultValue:(float)defaultValue
{
id obj = [self getValueForKey:key defaultValue:nil];
if (nil == obj)
{
return defaultValue;
}
if ([self isPodFloatObj:obj])
return [obj floatValue];
else
{
NSLog(@"警告[%s],数据对象类型不符:%@",__FUNCTION__, key);
}
return defaultValue;
}
- (time_t)getTimeValueForKey:(NSString *)key defaultValue:(time_t)defaultValue {
NSString *stringTime = [self objectForKey:key];
if ((id)stringTime == [NSNull null]) {
stringTime = @"";
}
struct tm created;
time_t now;
time(&now);
if (stringTime) {
if (strptime([stringTime UTF8String], "%a %b %d %H:%M:%S %z %Y", &created) == NULL) {
strptime([stringTime UTF8String], "%a, %d %b %Y %H:%M:%S %z", &created);
}
return mktime(&created);
}
return defaultValue;
}
- (long long)getLongLongValueValueForKey:(NSString *)key defaultValue:(long long)defaultValue {
id obj = [self getValueForKey:key defaultValue:nil];
if (nil == obj)
{
return defaultValue;
}
if ([self isPodInt64Obj:obj])
return [obj longLongValue];
else
{
NSLog(@"警告[%s],数据对象类型不符:%@",__FUNCTION__, key);
}
return defaultValue;
}
- (NSString *)getStringValueForKey:(NSString *)key defaultValue:(NSString *)defaultValue
{
id obj = [self getValueForKey:key defaultValue:nil];
if (nil == obj)
{
return defaultValue;
}
if ([self isNSTypeObj:obj andType:[NSString class]])
return obj;
else
{
NSLog(@"警告[%s],数据对象类型不符:%@",__FUNCTION__, key);
}
return defaultValue;
return [self objectForKey:key] == nil || [self objectForKey:key] == [NSNull null] ? defaultValue : [self objectForKey:key];
}
-(id)getValueForKey:(NSString*)key defaultValue:(id)defaultValue
{
return [self objectForKey:key] == nil || [self objectForKey:key] == [NSNull null]
? defaultValue : [self objectForKey:key];
}
-(CGPoint)getPointForKey:(NSString*)xKey yKey:(NSString*)yKey defaultValue:(CGPoint)defaultValue
{
CGPoint tmp = CGPointZero;
tmp.x = [self getFloatValueForKey:xKey defaultValue:defaultValue.x];
tmp.y = [self getFloatValueForKey:yKey defaultValue:defaultValue.y];
return tmp;
}
@end
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原文地址：http://www.cnblogs.com/decwang/p/4705199.html
