*:first-child {
margin-top: 0 !important; }
body > *:last-child {
margin-bottom: 0 !important; }

a {
color: #4183C4; }
a.absent {
color: #cc0000; }
a.anchor {
display: block;
padding-left: 30px;
margin-left: -30px;
cursor: pointer;
position: absolute;
top: 0;
left: 0;
bottom: 0; }

h1, h2, h3, h4, h5, h6 {
margin: 20px 0 10px;
padding: 0;
font-weight: bold;
-webkit-font-smoothing: antialiased;
cursor: text;
position: relative; }

h1:hover a.anchor, h2:hover a.anchor, h3:hover a.anchor, h4:hover a.anchor, h5:hover a.anchor, h6:hover a.anchor {
background: url(data:image/png;base64,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) no-repeat 10px center;
text-decoration: none; }

h1 tt, h1 code {
font-size: inherit; }

h2 tt, h2 code {
font-size: inherit; }

h3 tt, h3 code {
font-size: inherit; }

h4 tt, h4 code {
font-size: inherit; }

h5 tt, h5 code {
font-size: inherit; }

h6 tt, h6 code {
font-size: inherit; }

h1 {
font-size: 28px;
color: black; }

h2 {
font-size: 24px;
border-bottom: 1px solid #cccccc;
color: black; }

h3 {
font-size: 18px; }

h4 {
font-size: 16px; }

h5 {
font-size: 14px; }

h6 {
color: #777777;
font-size: 14px; }

p, blockquote, ul, ol, dl, li, table, pre {
margin: 15px 0; }

hr {
background: transparent url(data:image/png;base64,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) repeat-x 0 0;
border: 0 none;
color: #cccccc;
height: 4px;
padding: 0;
}

body > h2:first-child {
margin-top: 0;
padding-top: 0; }
body > h1:first-child {
margin-top: 0;
padding-top: 0; }
body > h1:first-child + h2 {
margin-top: 0;
padding-top: 0; }
body > h3:first-child, body > h4:first-child, body > h5:first-child, body > h6:first-child {
margin-top: 0;
padding-top: 0; }

a:first-child h1, a:first-child h2, a:first-child h3, a:first-child h4, a:first-child h5, a:first-child h6 {
margin-top: 0;
padding-top: 0; }

h1 p, h2 p, h3 p, h4 p, h5 p, h6 p {
margin-top: 0; }

li p.first {
display: inline-block; }
li {
margin: 0; }
ul, ol {
padding-left: 30px; }

ul :first-child, ol :first-child {
margin-top: 0; }

dl {
padding: 0; }
dl dt {
font-size: 14px;
font-weight: bold;
font-style: italic;
padding: 0;
margin: 15px 0 5px; }
dl dt:first-child {
padding: 0; }
dl dt > :first-child {
margin-top: 0; }
dl dt > :last-child {
margin-bottom: 0; }
dl dd {
margin: 0 0 15px;
padding: 0 15px; }
dl dd > :first-child {
margin-top: 0; }
dl dd > :last-child {
margin-bottom: 0; }

blockquote {
border-left: 4px solid #dddddd;
padding: 0 15px;
color: #777777; }
blockquote > :first-child {
margin-top: 0; }
blockquote > :last-child {
margin-bottom: 0; }

table {
padding: 0;border-collapse: collapse; }
table tr {
border-top: 1px solid #cccccc;
background-color: white;
margin: 0;
padding: 0; }
table tr:nth-child(2n) {
background-color: #f8f8f8; }
table tr th {
font-weight: bold;
border: 1px solid #cccccc;
margin: 0;
padding: 6px 13px; }
table tr td {
border: 1px solid #cccccc;
margin: 0;
padding: 6px 13px; }
table tr th :first-child, table tr td :first-child {
margin-top: 0; }
table tr th :last-child, table tr td :last-child {
margin-bottom: 0; }

img {
max-width: 100%; }

span.frame {
display: block;
overflow: hidden; }
span.frame > span {
border: 1px solid #dddddd;
display: block;
float: left;
overflow: hidden;
margin: 13px 0 0;
padding: 7px;
width: auto; }
span.frame span img {
display: block;
float: left; }
span.frame span span {
clear: both;
color: #333333;
display: block;
padding: 5px 0 0; }
span.align-center {
display: block;
overflow: hidden;
clear: both; }
span.align-center > span {
display: block;
overflow: hidden;
margin: 13px auto 0;
text-align: center; }
span.align-center span img {
margin: 0 auto;
text-align: center; }
span.align-right {
display: block;
overflow: hidden;
clear: both; }
span.align-right > span {
display: block;
overflow: hidden;
margin: 13px 0 0;
text-align: right; }
span.align-right span img {
margin: 0;
text-align: right; }
span.float-left {
display: block;
margin-right: 13px;
overflow: hidden;
float: left; }
span.float-left span {
margin: 13px 0 0; }
span.float-right {
display: block;
margin-left: 13px;
overflow: hidden;
float: right; }
span.float-right > span {
display: block;
overflow: hidden;
margin: 13px auto 0;
text-align: right; }

code, tt {
margin: 0 2px;
padding: 0 5px;
white-space: nowrap;
border: 1px solid #eaeaea;
background-color: #f8f8f8;
border-radius: 3px; }

pre code {
margin: 0;
padding: 0;
white-space: pre;
border: none;
background: transparent; }

.highlight pre {
background-color: #f8f8f8;
border: 1px solid #cccccc;
font-size: 13px;
line-height: 19px;
overflow: auto;
padding: 6px 10px;
border-radius: 3px; }

pre {
background-color: #f8f8f8;
border: 1px solid #cccccc;
font-size: 13px;
line-height: 19px;
overflow: auto;
padding: 6px 10px;
border-radius: 3px; }
pre code, pre tt {
background-color: transparent;
border: none; }

sup {
font-size: 0.83em;
vertical-align: super;
line-height: 0;
}
* {
-webkit-print-color-adjust: exact;
}
@media screen and (min-width: 914px) {
body {
width: 854px;
margin:0 auto;
}
}
@media print {
table, pre {
page-break-inside: avoid;
}
pre {
word-wrap: break-word;
}
}
-->
code[class*="language-"],
pre[class*="language-"] {
background: #f5f2f0;
}

/* Inline code */
:not(pre) > code[class*="language-"] {
padding: .1em;
border-radius: .3em;
white-space: normal;
}

.token.comment,
.token.prolog,
.token.doctype,
.token.cdata {
color: slategray;
}

.token.punctuation {
color: #999;
}

.namespace {
opacity: .7;
}

.token.property,
.token.tag,
.token.boolean,
.token.number,
.token.constant,
.token.symbol,
.token.deleted {
color: #905;
}

.token.selector,
.token.attr-name,
.token.string,
.token.char,
.token.builtin,
.token.inserted {
color: #690;
}

.token.operator,
.token.entity,
.token.url,
.language-css .token.string,
.style .token.string {
color: #a67f59;
background: hsla(0, 0%, 100%, .5);
}

.token.atrule,
.token.attr-value,
.token.keyword {
color: #07a;
}

.token.function {
color: #DD4A68;
}

.token.regex,
.token.important,
.token.variable {
color: #e90;
}

.token.important,
.token.bold {
font-weight: bold;
}
.token.italic {
font-style: italic;
}

.token.entity {
cursor: help;
}
-->

按钮细节

文章概要：

1、内部子控件

2、按钮拉伸问题

    2-1、代码拉伸

    2-2、无代码拉伸

内部子控件

如果想要改变按钮内部子控件的属性，只能自定义按钮

• 自定义按钮：调整内部子控件的frame
  • 方式1：实现titleRectForContentRect:和imageRectForContentRect:方法，分别返回titleLabel和imageView的frame
  • 方式2：在layoutSubviews方法中设置
• 内边距

// 设置按钮内容的内边距（影响到imageView和titleLabel）

@property(nonatomic)          UIEdgeInsets contentEdgeInsets;

// 设置titleLabel的内边距（影响到titleLabel）

@property(nonatomic)          UIEdgeInsets titleEdgeInsets;

// 设置imageView的内边距（影响到imageView）

@property(nonatomic)          UIEdgeInsets imageEdgeInsets;

调整内部子控件的frame的方法1但是这样写很麻烦，而且有个问题：

　　如果两个方法内部的参数互相依赖，但是却不清楚两个方法的执行顺序，所以容易出现异常。

然后建议使用调整内部子控件的frame方法2，在layoutSubviews中设置子控件的frame。

按钮其实不需要添加子控件的，因为按钮内部有两个子控件UIImage和UILabel，可以直接使用，但是对于这两个子控件使用有一些注意点：UIButton的子控件的iamgeView.image和titleLabel.text不能直接设置值，因为这两个值(或许还有别的值，可以通过看源码查看注释)是需要有设置状态属性值，如果没有设置状态，直接访问其属性更改会失效。

所以，以后按钮内置子控件的属性，要先确认是否需要分状态显示的。

如果想要该自己改变子控件titileLabel的字体，直接拿出font赋值，因为font不分状态

按钮拉伸问题

代码拉伸

在按钮使用了背景图片之后，特别是圆角图片，如果将按钮拉伸很大，边角锯齿显示就很明显了，也很难看。

所以我们需要将按钮拉伸问题进行处理：

使用UIImage对象的一个方法resizeable...可拉伸的意思

瓦片模式：拉伸后，会将可拉伸的部分拷贝铺设一块一块

拉伸模式：拉伸后，会直接将可拉伸部分直接拉大

瓦片模式，如果可拉伸部分是纯单色，跟拉伸模式没区别

• iOS5之前

// 只拉伸中间的1x1区域

- (UIImage *)stretchableImageWithLeftCapWidth:(NSInteger)leftCapWidth topCapHeight:(NSInteger)topCapHeight;

• iOS5开始

- (UIImage *)resizableImageWithCapInsets:(UIEdgeInsets)capInsets;

- (UIImage *)resizableImageWithCapInsets:(UIEdgeInsets)capInsets resizingMode:(UIImageResizingMode)resizingMode;

最后一般项目中这个图片拉伸的复用的功能我们可以封装在内部，

我们先将这个功能封装进方法，方法名是：resizableImage

那么写在谁的内部比较合适,也就是谁做这个功能最合适呢？

当然是UIImage，那么就有两种方式，

    1、分类类别拓展UIImage的方法，2、在继承UIImage自定义类中写

注意：类别拓展拓展成类方法比较合适哦，不然你还需要通过alloc-init创建UIImage对象，然后调用这个拓展的类别方法。

无代码拉伸

在xcode上设置，直接好使用，不用写代码，一劳永逸。连前面导入类别文件名都不需要了。