Iphone文本切頁代碼

//!如果不是HTML，可以把<p></p>改爲\n或者\r\n
-(NSString *)doPagination:(NSString *)pageContent pageNumber:(NSInteger)number
                                 fontSize:(NSInteger)size lineHeight:(NSInteger)lheight pageHeight:(NSInteger)pheight  pageWidth:(NSInteger) pwidth{
    UIFont *tfont=[UIFont fontWithName:@"Helvetica" size:size];
    CGFloat singleHeight=[@"中" sizeWithFont:tfont constrainedToSize:CGSizeMake((float)pwidth, 9999.0) lineBreakMode:UILineBreakModeCharacterWrap ].height;
    NSInteger maxline_per_page=(int) (pheight/singleHeight);
    NSArray *paragraphSplit=[pageContent componentsSeparatedByString:@"<p></p>"];
    NSString *breakString=@"\n\n";
    NSString *contentTrim;
    NSInteger totalLines=0;
    NSMutableString *tempString=[NSMutableString string];
    NSString *leftString;
    CGSize csize;
    NSMutableArray *bookPages=[NSMutableArray array];
    for (NSString *para in paragraphSplit){
        contentTrim=[para stringByReplacingOccurrencesOfString:@"<p>" withString:breakString];
        csize=[contentTrim sizeWithFont:tfont constrainedToSize:CGSizeMake((float)pwidth, MAXFLOAT) lineBreakMode:UILineBreakModeCharacterWrap ];
        totalLines+=(int)(csize.height/singleHeight);
        leftString=contentTrim;
        if (totalLines > maxline_per_page){
            totalLines-=(int)(csize.height/singleHeight);
            for(int i=0;i<[contentTrim length];i++){
                NSString *calcString=[contentTrim substringWithRange:NSMakeRange(0, i)];
                csize=[calcString sizeWithFont:tfont constrainedToSize:CGSizeMake((float)pwidth, MAXFLOAT) lineBreakMode:UILineBreakModeCharacterWrap ];
                totalLines=totalLines+(int)(csize.height/singleHeight);
                if (totalLines>maxline_per_page)
                {
                    i--;
                    if ([calcString length]>0) [tempString appendString:[calcString substringToIndex:([calcString length]-1)]];
                    if (i>0) leftString=[contentTrim substringFromIndex:i]; else leftString=@"";
                    [bookPages addObject:[[tempString copy]autorelease]];
                    totalLines=(int)([leftString sizeWithFont:tfont constrainedToSize:CGSizeMake((float)pwidth, MAXFLOAT) lineBreakMode:UILineBreakModeCharacterWrap ].height/singleHeight);
                    [tempString setString:@""];
                    break;
                }
                else totalLines=totalLines-(int)(csize.height/singleHeight);
            }
        }
        [tempString appendString:leftString];
    }
    [bookPages addObject:[[tempString copy]autorelease]];
    self.bookContent=[NSArray arrayWithArray:bookPages];
    return [bookPages objectAtIndex:number];
}
</p>