NSAttributedStringを作成するために、（簡略化された）HTML文字列を解析する例を示すと便利だと思いました。
それは完全ではありません-初心者のために<b>および<i>タグのみを処理し、エラー処理を気にしません-うまくいけば、NSXMLParserDelegateを開始する方法の有用な例でもあります...
@interface ExampleHTMLStringToAttributedString : NSObject<NSXMLParserDelegate>
+(NSAttributedString*) getAttributedStringForHTMLText:(NSString*)htmlText WithFontSize:(CGFloat)fontSize;
@end
@interface ExampleHTMLStringToAttributedString()
@property NSString *mpString;
@property NSMutableAttributedString *mpAttributedString;
@property CGFloat mfFontSize;
@property NSMutableString *appendThisString;
@property BOOL mbIsBold;
@property BOOL mbIsItalic;
@end
@implementation ExampleHTMLStringToAttributedString
@synthesize mpString;
@synthesize mfFontSize;
@synthesize mpAttributedString;
@synthesize appendThisString;
@synthesize mbIsBold;
@synthesize mbIsItalic;
+(NSAttributedString*) getAttributedStringForHTMLText:(NSString*)htmlText WithFontSize:(CGFloat)fontSize {
ExampleHTMLStringToAttributedString *me = [[ExampleHTMLStringToAttributedString alloc] initWithString:htmlText];
return [me getAttributedStringWithFontSize:fontSize];
}
- (id)initWithString:(NSString*)inString {
self = [super init];
if (self) {
if ([inString hasPrefix:@""]) {
mpString = inString;
} else {
mpString = [NSString stringWithFormat:@"%@", inString];
}
mpAttributedString = [NSMutableAttributedString new];
}
return self;
}
-(NSAttributedString*) getAttributedStringWithFontSize:(CGFloat)fontSize {
mfFontSize = fontSize;
// Parse the XML
NSXMLParser *parser = [[NSXMLParser alloc] initWithData:[mpString dataUsingEncoding:NSUTF8StringEncoding]];
parser.delegate = self;
if (![parser parse]) {
return nil;
}
return mpAttributedString;
}
-(void) appendTheAccumulatedText {
UIFont *theFont = nil;
if (mbIsBold && mbIsItalic) {
// http://stackoverflow.com/questions/1384181/italic-bold-and-underlined-font-on-iphone
theFont = [UIFont fontWithName:@"Helvetica-BoldOblique" size:mfFontSize];
} else if (mbIsBold) {
theFont = [UIFont boldSystemFontOfSize:mfFontSize];
} else if (mbIsItalic) {
theFont = [UIFont italicSystemFontOfSize:mfFontSize];
} else {
theFont = [UIFont systemFontOfSize:mfFontSize];
}
NSAttributedString *appendThisAttributedString =
[[NSAttributedString alloc]
initWithString:appendThisString
attributes:@{NSFontAttributeName : theFont}];
[mpAttributedString appendAttributedString:appendThisAttributedString];
[appendThisString setString:@""];
}
#pragma NSXMLParserDelegate delegate
-(void)parserDidStartDocument:(NSXMLParser *)parser{
appendThisString = [NSMutableString new];
mbIsBold = NO;
mbIsItalic = NO;
}
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict {
if ([elementName isEqualToString:@"body"]){
} else if ([elementName isEqualToString:@"i"]) {
[self appendTheAccumulatedText];
mbIsItalic = YES;
} else if ([elementName isEqualToString:@"b"]) {
[self appendTheAccumulatedText];
mbIsBold = YES;
}
}
-(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName{
if ([elementName isEqualToString:@"body"]){
[self appendTheAccumulatedText];
} else if ([elementName isEqualToString:@"i"]) {
[self appendTheAccumulatedText];
mbIsItalic = NO;
} else if ([elementName isEqualToString:@"b"]) {
[self appendTheAccumulatedText];
mbIsBold = NO;
}
}
-(void)parserDidEndDocument:(NSXMLParser *)parser{
}
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string {
[appendThisString appendString:string];
}
- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError {
}
@end
使用するには、次のようにします。
self.myTextView.attributedText = [ExampleHTMLStringToAttributedString getAttributedStringForHTMLText:@"this is <b>bold</b> text" WithFontSize:self.myTextView.pointSize];