Question

我无法导入以XML文件编码的图像数据。以下是我的类的代码，我在其中读取XML文件并尝试从编码数据中获取照片。

编辑1

我没有任何错误，但我总是在“artXML.photo”上获得一个空值....

任何人都可以指出可能出现的问题吗？

-(void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {

    valoreLetto = [valoreLetto stringByAppendingString:string];
}

-(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName 
  namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName 
{

    if([elementName isEqualToString:@"photo"]) {

        NSData *aData;
        aData = [NSData dataWithBase64EncodedString:valoreLetto];

        //valoreLetto contains a value like X'FFD8FFE000....', from the blob representation of an image

        artXML.photo = [UIImage imageWithData:aData];
    }

}

@end

@interface NSData (ParserXmlArticoli)

-(id)dataWithBase64EncodedString:(NSString *)string;   
-(NSString *)base64Encoding;
@end


static const char encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";


@implementation NSData (ParserXmlArticoli)

-(id)dataWithBase64EncodedString:(NSString *)string;
{

    if (string == nil)
        [NSException raise:NSInvalidArgumentException format:nil];
    if ([string length] == 0)
        return [NSData data];

    static char *decodingTable = NULL;
    if (decodingTable == NULL)
    {

        decodingTable = malloc(256);
        if (decodingTable == NULL)
            return nil;
        memset(decodingTable, CHAR_MAX, 256);
        NSUInteger i;
        for (i = 0; i < 64; i++)
            decodingTable[(short)encodingTable[i]] = i;
    }

    const char *characters = [string cStringUsingEncoding:NSASCIIStringEncoding];
    if (characters == NULL)  
        return nil;
    char *bytes = malloc((([string length] + 3) / 4) * 3);
    if (bytes == NULL)
        return nil;
    NSUInteger length = 0;

    NSUInteger i = 0;
    while (YES)

    {

        char buffer[4];
        short bufferLength;
        for (bufferLength = 0; bufferLength < 4; i++)
        {

            if (characters[i] == '\0')
                break;
            if (isspace(characters[i]) || characters[i] == '=')
                continue;
            buffer[bufferLength] = decodingTable[(short)characters[i]];
            if (buffer[bufferLength++] == CHAR_MAX)      
            {

                free(bytes);
                return nil;

            }

        }

        if (bufferLength == 0)
            break;
        if (bufferLength == 1)

        {

            free(bytes);
            return nil;

        }

        bytes[length++] = (buffer[0] << 2) | (buffer[1] >> 4);
        if (bufferLength > 2)
            bytes[length++] = (buffer[1] << 4) | (buffer[2] >> 2);
        if (bufferLength > 3)
            bytes[length++] = (buffer[2] << 6) | buffer[3];

    }

    realloc(bytes, length);
    return [NSData dataWithBytesNoCopy:bytes length:length];

}

-(NSString *)base64Encoding;

{

if ([self length] == 0)
        return @"";

    char *characters = malloc((([self length] + 2) / 3) * 4);
    if (characters == NULL)
        return nil;
    NSUInteger length = 0;

    NSUInteger i = 0;
    while (i < [self length])

    {

                char buffer[3] = {0,0,0};
        short bufferLength = 0;
        while (bufferLength < 3 && i < [self length])
            buffer[bufferLength++] = ((char *)[self bytes])[i++];

        characters[length++] = encodingTable[(buffer[0] & 0xFC) >> 2];
        characters[length++] = encodingTable[((buffer[0] & 0x03) << 4) | ((buffer[1] & 0xF0) >> 4)];
        if (bufferLength > 1)
            characters[length++] = encodingTable[((buffer[1] & 0x0F) << 2) | ((buffer[2] & 0xC0) >> 6)];
        else characters[length++] = '=';
        if (bufferLength > 2)
            characters[length++] = encodingTable[buffer[2] & 0x3F];
        else characters[length++] = '=';

    }

    return [[[NSString alloc] initWithBytesNoCopy:characters length:length encoding:NSASCIIStringEncoding freeWhenDone:YES] autorelease];

}

@end

Answer 1

我假设您的意思是来自字符串或输入流。检查前面这个帖子：Reading binary image data from a web service into UIImage

为什么我不能使用iPhone应用程序中的代码解析XML文件中的图像？

1 个答案: