Question

I want to modify xml attribute using objective c on some action
for example, i have button on screen and my xml tag is

mynode attribute1=”” attribute2=”” attribute3=””
/mynode

if initial value of attribute3 is NO, on tapping button i want to change it to YES and write it to xml file which is in projects directory.
Please help me if anyone know about this.
I have tried using GDataXML addattribute method, but not able to modify tag.

Answer 1

It is not possible to edit the XML file in Objective – c. If you want to do this, then you needs to create your own xml file or you can append the tags to the existing xml.
Please refer the following code where I am created my own xml to append the bytes array of a image & adding it to the original xml.

//Encode all the data and get the XML string 
            NSString *theXML = [[NSString alloc] 
                                initWithBytes: [clipSvgData bytes] 
                                length:[clipSvgData length] 
                                encoding:NSUTF8StringEncoding];

            //Returns the substring of an main xml file by excluding the extra xml tags
            NSString *startTag = @"<svg";
            NSString *endTag = @"</svg>";
            NSString *responseString;

            NSScanner *scanner = [[NSScanner alloc] initWithString:theXML];
            [scanner scanUpToString:startTag intoString:nil];
            scanner.scanLocation += [startTag length];
            [scanner scanUpToString:endTag intoString:&responseString];
            [scanner release];

            //Remove the SVG tag from main xml
            NSString *startTag1 = @">";
            NSString *endTag1 = @"</svg>";
            NSString *responseString1;

            NSScanner *scanner1 = [[NSScanner alloc] initWithString:[NSString stringWithFormat:@"<svg %@ </svg>",responseString]];
            [scanner1 scanUpToString:startTag1 intoString:nil];
            scanner1.scanLocation += [startTag1 length];
            [scanner1 scanUpToString:endTag1 intoString:&responseString1];
            [scanner1 release];

    NSString *strSVGNode = [NSString stringWithFormat:@"<svg version=\"1.1\" id=\"Layer_1\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\" x=\"%fpx\" y=\"%fpx\" width=\"%fpx\" height=\"%fpx\" viewBox=\"0 0 141.73 141.73\" enable-background=\"new 0 0 141.73 141.73\"  xml:space=\"preserve\" preserveAspectRatio=\"none\">", imgXPos, imgYPos, imgWidth, imgHeight];

    NSString *strClipXml = [NSString stringWithFormat:@"%@ %@ </svg></g>",strSVGNode ,responseString1];

    //Add the created SVG as new node in main SVG file.
    GDataXMLNode *clipNode = [GDataXMLNode textWithStringValue:[NSString stringWithFormat:@"%@",strClipXml]];
    [xmlDocument.rootElement addChild:clipNode];

You can modify it as per your requirement.