iOS中NSString轉換成HEX（十六進制）-NSData轉換成int

NSString *str = @"0xff055008";  
//先以16爲參數告訴strtoul字符串參數表示16進制數字，而後使用0x%X轉爲數字類型  
unsigned long red = strtoul([str UTF8String],0,16);  
//strtoul若是傳入的字符開頭是「0x」,那麼第三個參數是0，也是會轉爲十六進制的,這樣寫也能夠：  
unsigned long red = strtoul([@"0x6587" UTF8String],0,0);  
NSLog(@"轉換完的數字爲：%lx",red);  

// 十六進制轉換爲普通字符串的。   
+ (NSString *)stringFromHexString:(NSString *)hexString { //   
   
charchar *myBuffer = (charchar *)malloc((int)[hexString length] / 2 + 1);   
bzero(myBuffer, [hexString length] / 2 + 1);   
for (int i = 0; i < [hexString length] - 1; i += 2) {   
unsigned int anInt;   
NSString * hexCharStr = [hexString substringWithRange:NSMakeRange(i, 2)];   
NSScanner * scanner = [[[NSScanner alloc] initWithString:hexCharStr] autorelease];   
[scanner scanHexInt:&anInt];   
myBuffer[i / 2] = (char)anInt;   
}   
NSString *unicodeString = [NSString stringWithCString:myBuffer encoding:4];   
NSLog(@"------字符串=======%@",unicodeString);   
return unicodeString;   
   
   
}   

//普通字符串轉換爲十六進制的。   
   
+ (NSString *)hexStringFromString:(NSString *)string{   
NSData *myD = [string dataUsingEncoding:NSUTF8StringEncoding];   
Byte *bytes = (Byte *)[myD bytes];   
//下面是Byte 轉換爲16進制。   
NSString *hexStr=@"";   
for(int i=0;i<[myD length];i++)   
   
{   
NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff];///16進制數   
   
if([newHexStr length]==1)   
   
hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];   
   
else   
   
hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];   
}   
return hexStr;   
}  


//int 轉data  
int i = 1;   
NSData *data = [NSData dataWithBytes: &i length: sizeof(i)];   
//data 轉int  
int i;   
[data getBytes: &i length: sizeof(i)];