关于drawInRect: withAttributes: 等新方法的使用

来源：互联网发布：theone智能钢琴软件编辑：程序博客网时间：2024/05/21 11:03

新的方法采用的是 attributes，attributes参数需要的是一个数组
我们常用的有几个：

<code class="hljs ruby has-numbering">    <span class="hljs-constant">NSMutableParagraphStyle</span>* paragraphStyle = [[<span class="hljs-constant">NSParagraphStyle</span> defaultParagraphStyle] mutableCopy];    paragraphStyle.lineBreakMode = <span class="hljs-constant">NSLineBreakByCharWrapping</span>;    <span class="hljs-constant">NSDictionary</span>* dic = @{<span class="hljs-constant">NSFontAttributeName</span><span class="hljs-symbol">:font</span>,<span class="hljs-constant">NSParagraphStyleAttributeName</span><span class="hljs-symbol">:paragraphStyle</span>,<span class="hljs-constant">NSForegroundColorAttributeName</span><span class="hljs-symbol">:</span>[<span class="hljs-constant">UIColor</span> lightGrayColor]};</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li><li>3</li></ul>

通过设置 NSParagraphStyleAttributeName，我们可以设置string的段落风格，比如 lineBreakMode
NSForegroundColorAttributeName 字体颜色
eg：
原先可以这样写：

<code class="hljs mel has-numbering">CGSize <span class="hljs-keyword">size</span> = [<span class="hljs-keyword">text</span> sizeWithFont:font constrainedToSize:CGSizeMake(<span class="hljs-number">300</span>, MAXFLOAT)lineBreakMode:NSLineBreakByCharWrapping];[<span class="hljs-keyword">text</span> drawInRect:CGRectMake(<span class="hljs-number">10</span>,<span class="hljs-number">10</span>,<span class="hljs-number">300</span>, <span class="hljs-keyword">size</span>.height) withFont:font lineBreakMode:NSLineBreakByCharWrapping];</code><ul style="display: block;" class="pre-numbering"><li>1</li><li>2</li></ul>

iOS7 之后需要切换新方法，如下：

<code class="hljs mel has-numbering">    NSMutableParagraphStyle* paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];    paragraphStyle.lineBreakMode = NSLineBreakByCharWrapping;    NSDictionary<span class="hljs-variable">*attribute</span> = @{NSFontAttributeName:font,NSParagraphStyleAttributeName:paragraphStyle};    CGSize <span class="hljs-keyword">size</span> = [<span class="hljs-keyword">text</span> boundingRectWithSize:CGSizeMake(<span class="hljs-number">300</span>, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:attribute context:nil].<span class="hljs-keyword">size</span>;    [<span class="hljs-keyword">text</span> drawWithRect:CGRectMake(<span class="hljs-number">10</span>, <span class="hljs-number">10</span>,<span class="hljs-number">300</span>, <span class="hljs-keyword">size</span>.height) options:NSStringDrawingUsesLineFragmentOrigin attributes:attribute context:nil];</code>

0 0