<原>DTCoreText學習(一)－DTAttributedTextCell原理

其實DTCoreText自帶的cell就很好用了，解析html並且顯示html都很方便，只要設置DTAttributedTextCell的

- (void)setHTMLString:(NSString *)html方法即可，其原理如下面所示

- (id)initWithReuseIdentifier:(NSString *)reuseIdentifier accessoryType:(UITableViewCellAccessoryType)accessoryType
{
    self = [super initWithStyle:UITableViewCellStyleDefault reuseIdentifier:reuseIdentifier];
    if (self) 
    {
        // don't know size jetzt because there's no string in it
        _attributedTextContextView = [[DTAttributedTextContentView alloc] initWithFrame:CGRectZero];
        _attributedTextContextView.edgeInsets = UIEdgeInsetsMake(5, 5, 5, 5);
        [self.contentView addSubview:_attributedTextContextView];
    }
    return self;
}

這是DTAttributedTextCell中定義的初始化方法  在cell的contentView上覆蓋了一層DTAttributedTextContentView 而我們的html正是通過它顯示出來的，

- (void)setHTMLString:(NSString *)html
{
    // we don't preserve the html but compare it's hash
    NSUInteger newHash = [html hash];
    
    if (newHash == _htmlHash)
    {
        return;
    }
    
    _htmlHash = newHash;
    
    NSData *data = [html dataUsingEncoding:NSUTF8StringEncoding];
    NSAttributedString *string = [[NSAttributedString alloc] initWithHTML:data documentAttributes:NULL];
    self.attributedString = string;
}

- (void)setAttributedString:(NSAttributedString *)attributedString
{
    if (_attributedString != attributedString)
    {
        _attributedString = attributedString;
        
        // passthrough
        _attributedTextContextView.attributedString = _attributedString;
    }
}

_attributedString的類型是NSAttributedString  我們把要顯示的html傳遞給 setHTMLString:(NSString *)html   最后調用self.attributedString = string; 后進入setAttributedString:(NSAttributedString *)attributedString

最終設置  _attributedTextContextView.attributedString = _attributedString；達到顯示的目的

DTAttributedTextCell常用的就這幾個方法  一般了解這幾個方法的使用  就能簡單的實現利用 DTAttributedTextCell解析並顯示html