欢迎动画

1.安装后首次启动有，说明这个轮播页只运行一次，以后就不再出现了； 
2.每次启动程序都会首先运行一个方法：

<code class="hljs coffeescript has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">func application<span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?)</span> -></span> Bool {        <span class="hljs-regexp" style="color: rgb(0, 136, 0); box-sizing: border-box;">//</span> Override point <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> customization after application launch.        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">true</span>    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

这个方法，我们没有设置跟控制，项目就会默认是ViewController。 
下面问题就简单了，我们在这个方法里面做切换跟控制器的操作。

• AppDelegate里切换跟控制器

在上面的方法里面加入：（IndexViewController 轮播页控制器）

<code class="hljs coffeescript has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;"> <span class="hljs-reserved" style="box-sizing: border-box;">let</span> indexVC = IndexViewController(); <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">window</span>?.rootViewController = indexVC;</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

这样我们就可以切换跟控制器了。

• 运行一次 
  运行一次，这好做，我们可以在NSUserDefaults里面设置一个键值对。运行：

<code class="hljs coffeescript has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">func application<span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?)</span> -></span> Bool</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

这个方法时，我们先读这个键值对，里面有值，我们就进入项目默认的控制器ViewController，没有就进入IndexViewController。 
在IndexViewController里面我们给这个键值对设置一个值。也就是说，只要运行过IndexViewController之后，这个键值对有始终会存在一个值，那么app以后的启动就不会进入IndexViewController，而是默认的ViewController。

<code class="hljs coffeescript has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">func application<span class="hljs-function" style="box-sizing: border-box;"><span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?)</span> -></span> Bool {        <span class="hljs-regexp" style="color: rgb(0, 136, 0); box-sizing: border-box;">//</span> Override point <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> customization after application launch.        <span class="hljs-regexp" style="color: rgb(0, 136, 0); box-sizing: border-box;">//</span> 设置跟控制器        <span class="hljs-reserved" style="box-sizing: border-box;">let</span>  launch =  NSUserDefaults.standardUserDefaults().valueForKey(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"firstLaunch"</span>);        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> launch == nil {            <span class="hljs-reserved" style="box-sizing: border-box;">let</span> indexVC = IndexViewController();            <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">window</span>?.rootViewController = indexVC;        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span>{            <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">window</span>?.rootViewController = ViewController();        }        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">true</span>    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li></ul>

• IndexViewController制作轮播页/切换跟控制器/设置键值对 
  在app进入IndexViewController里面后，又会存在一个问题？轮播页轮播完后，怎么进入app呢？ 
  这回时候我们就又需要切换一次跟控制器为默认的跟控制器。

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; background-color: transparent; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-top-left-radius: 0px; border-top-right-radius: 0px; border-bottom-right-radius: 0px; border-bottom-left-radius: 0px; word-wrap: normal; background-position: initial initial; background-repeat: initial initial;">// 立即体验按钮点击事件 @IBAction func btnClick(sender: UIButton) {        NSUserDefaults<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.standardUserDefaults</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.setValue</span>(firstLaunch, forKey: firstLaunch)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>        let window = UIApplication<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.sharedApplication</span>()<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.keyWindow</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>        if ((window?<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.rootViewController</span>) != nil) {            window?<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.rootViewController</span>?<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.removeFromParentViewController</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>            window?<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.rootViewController</span> = nil<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>        }        window!<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.rootViewController</span> = ViewController()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>        let cATransition = CATransition()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>        cATransition<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.duration</span> = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0.3</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>        cATransition<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.type</span> = kCATransitionFade<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>        window?<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.layer</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.addAnimation</span>(cATransition, forKey: nil)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>        window!<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.makeKeyWindow</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; background-color: rgb(238, 238, 238); top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right;"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li></ul>

在切换之前我们也把上面提到的键值对设置了一个值，这样以后app启动后，这键就有值了。

效果图