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iOS中的事件
在用户使用app过程中,会产生各种各样的事件;iOS中的事件可以分为3大类型:
响应者对象–UIResponder
在iOS中不是任何对象都能处理事件,只有继承了UIResponder的对象才能接收并处理事件。我们称之为“响应者对象”
UIApplication、UIViewController、UIView都继承自UIResponder,因此它们都是响应者对象,都能够接收并处理事件
UIResponder内部提供了以下方法来处理事件
<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*触摸事件*/</span> - (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span>)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>; - (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span>)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>; - (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span>)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>; - (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span>)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>;</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><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>
这次主要是触摸事件,加速和远程控制事件可以先略过。
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">加速计事件 <span class="hljs-pp" style="box-sizing: border-box;">- <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>motionBegan:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEventSubtype</span>)</span>motion withEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event; - <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>motionEnded:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEventSubtype</span>)</span>motion withEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event; - <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>motionCancelled:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEventSubtype</span>)</span>motion withEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event;</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><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></ul>
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">远程控制事件 <span class="hljs-pp" style="box-sizing: border-box;">- <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>remoteControlReceivedWithEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event;</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>
UIView的触摸事件处理
UIView是UIResponder的子类,可以实现下列4个方法处理不同的触摸事件
1:一根或者多根手指开始触摸view,系统会自动调用view的下面方法
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pp" style="box-sizing: border-box;">- <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>touchesBegan:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">NSSet</span> *)</span>touches withEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
2:一根或者多根手指在view上移动,系统会自动调用view的下面方法(随着手指的移动,会持续调用该方法)
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pp" style="box-sizing: border-box;">- <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>touchesMoved:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">NSSet</span> *)</span>touches withEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
3:一根或者多根手指离开view,系统会自动调用view的下面方法
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pp" style="box-sizing: border-box;">- <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>touchesEnded:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">NSSet</span> *)</span>touches withEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
4:触摸结束前,某个系统事件(例如电话呼入)会打断触摸过程,系统会自动调用view的下面方法
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pp" style="box-sizing: border-box;">-<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>touchesCancelled:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">NSSet</span> *)</span>touches withEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event 提示:touches中存放的都是UITouch对象</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>
UITouch
当用户用一根手指触摸屏幕时,会创建一个与手指相关联的UITouch对象。
一根手指对应一个UITouch对象。
UITouch的作用。
保存着跟手指相关的信息,比如触摸的位置、时间、阶段。
当手指移动时,系统会更新同一个UITouch对象,使之能够一直保存该手指的触摸位置。
当手指离开屏幕时,系统会销毁相应的UITouch对象。
注意:iPhone开发中,要避免使用双击事件!
UITouch的属性
触摸产生时所处的窗口
<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@property</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">nonatomic</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">readonly</span>,retain) <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">UIWindow</span> *window;</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
触摸产生时所处的视图
<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@property</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">nonatomic</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">readonly</span>,retain) <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">UIView</span> *view;</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
短时间内点按屏幕的次数,可以根据tapCount判断单击、双击或更多的点击
<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@property</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">nonatomic</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">readonly</span>) NSUInteger tapCount;</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
记录了触摸事件产生或变化时的时间,单位是秒
<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@property</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">nonatomic</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">readonly</span>) <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSTimeInterval</span> timestamp;</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
当前触摸事件所处的状态
<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@property</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">nonatomic</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">readonly</span>) UITouchPhase phase;</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
UITouch的方法
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pp" style="box-sizing: border-box;">- <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">CGPoint</span>)</span>locationInView:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIView</span> *)</span>view;</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
返回值表示触摸在view上的位置
这里返回的位置是针对view的坐标系的(以view的左上角为原点(0, 0))
调用时传入的view参数为nil的话,返回的是触摸点在UIWindow的位置
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pp" style="box-sizing: border-box;">- <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">CGPoint</span>)</span>previousLocationInView:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIView</span> *)</span>view;</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
该方法记录了前一个触摸点的位置
UIEvent
每产生一个事件,就会产生一个UIEvent对象
UIEvent:称为事件对象,记录事件产生的时刻和类型
UIEvent常见属性
事件类型
<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@property</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">nonatomic</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">readonly</span>) UIEventType type; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@property</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">nonatomic</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">readonly</span>) UIEventSubtype subtype;</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>
事件产生的时间
<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">@property</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">nonatomic</span>,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">readonly</span>) <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSTimeInterval</span> timestamp;</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
UIEvent还提供了相应的方法可以获得在某个view上面的触摸对象(UITouch)
touches和event参数
一次完整的触摸过程,会经历3个状态:
触摸开始:
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pp" style="box-sizing: border-box;">- <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>touchesBegan:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">NSSet</span> *)</span>touches withEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
触摸移动:
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pp" style="box-sizing: border-box;">- <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>touchesMoved:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">NSSet</span> *)</span>touches withEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
触摸结束:
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pp" style="box-sizing: border-box;">- <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>touchesEnded:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">NSSet</span> *)</span>touches withEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
触摸取消(可能会经历):
<code class="hljs erlang has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pp" style="box-sizing: border-box;">- <span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(void)</span>touchesCancelled:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">NSSet</span> *)</span>touches withEvent:<span class="hljs-params" style="color: rgb(102, 0, 102); box-sizing: border-box;">(<span class="hljs-variable" style="box-sizing: border-box;">UIEvent</span> *)</span>event</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
1: 4个触摸事件处理方法中,都有NSSet *touches和UIEvent *event两个参数
2:一次完整的触摸过程中,只会产生一个事件对象,4个触摸方法都是同一个event参数
3:如果两根手指同时触摸一个view,那么view只会调用一次touchesBegan:withEvent:方法,touches参数中装着2个UITouch对象
4:如果这两根手指一前一后分开触摸同一个view,那么view会分别调用2次touchesBegan:withEvent:方法,并且每次调用时的touches参数中只包含一个UITouch对象
5:根据touches中UITouch的个数可以判断出是单点触摸还是多点触摸
事件的产生和传递
1:发生触摸事件后,系统会将该事件加入到一个由UIApplication管理的事件队列中
2:UIApplication会从事件队列中取出最前面的事件,并将事件分发下去以便处理,通常,先发送事件给应用程序的主窗口(keyWindow)
3:主窗口会在视图层次结构中找到一个最合适的视图来处理触摸事件,但是这仅仅是整个事件处理过程的第一步
4:找到合适的视图控件后,就会调用视图控件的touches方法来作具体的事件处理:
touchesBegan…
touchesMoved…
touchedEnded…
事件传递示例
触摸事件的传递是从父控件传递到子控件
如果点击了绿色的view (->)代表传递:
UIApplication -> UIWindow -> 白色 -> 绿色
点击了蓝色的view:
UIApplication -> UIWindow -> 白色 -> 橙色 -> 蓝色
点击了黄色的view:
UIApplication -> UIWindow -> 白色 -> 橙色 -> 蓝色 -> 黄色
如果父控件不能接收触摸事件,那么子控件就不可能接收到触摸事件(掌握)
如何找到最合适的控件来处理事件?
1> 自己是否能接收触摸事件?否,事件传递到此结束
2> 触摸点是否在自己身上?否,事件传递到此结束
3> 从后往前遍历子控件,重复前面的两个步骤
4> 如果没有符合条件的子控件,那么就自己最适合处理
UIView不接收触摸事件的三种情况
一:不接收用户交互
userInteractionEnabled = NO
二:隐藏
hidden = YES
三:透明
alpha = 0.0 ~ 0.01
当在这三种情况下的时候,UIView是不接受的。
注意:UIImageView的userInteractionEnabled默认就是NO,因此UIImageView以及它的子控件默认是不能接收触摸事件的
触摸事件处理的详细过程
用户点击屏幕后产生的一个触摸事件,经过一系列的传递过程后,会找到最合适的视图控件来处理这个事件。在找到最合适的视图控件后,就会调用控件的touches方法来作具体的事件处理。
touchesBegan…
touchesMoved…
touchedEnded…
这些touches方法的默认做法是将事件顺着响应者链条向上传递,将事件交给上一个响应者进行处理。
完整过程:
1> 先将事件对象由上往下传递(由父控件传递给子控件),找到最合适的控件来处理这个事件。
2> 调用最合适控件的touches….方法
3> 如果调用了[super touches….];就会将事件顺着响应者链条往上传递,传递给上一个响应者
4> 接着就会调用上一个响应者的touches….方法
响应者链条示意图
响应者链条:是由多个响应者对象连接起来的链条
作用:能很清楚的看见每个响应者之间的联系,并且可以让一个事件多个对象处理。
响应者对象:能处理事件的对象
响应者链的事件传递过程
1:如果view的控制器存在,就传递给控制器;如果控制器不存在,则将其传递给它的父视图
2:在视图层次结构的最顶级视图,如果也不能处理收到的事件或消息,则其将事件或消息传递给window对象进行处理
3:如果window对象也不处理,则其将事件或消息传递给UIApplication对象
4:如果UIApplication也不能处理该事件或消息,则将其丢弃
如何判断上一个响应者
1> 如果当前这个view是控制器的view,那么控制器就是上一个响应者
2> 如果当前这个view不是控制器的view,那么父控件就是上一个响应者
监听触摸事件的做法
如果想监听一个view上面的触摸事件,之前的做法是
1:自定义一个view。
2:实现view的touches方法,在方法内部实现具体处理代码。
3:通过touches方法监听view触摸事件,有很明显的几个缺点。
a:必须得自定义view。
b:由于是在view内部的touches方法中监听触摸事件,因此默认情况下,无法让其他外界对象监听view的触摸事件。
c:不容易区分用户的具体手势行为。
iOS 3.2之后,苹果推出了手势识别功能(Gesture Recognizer),在触摸事件处理方面,大大简化了开发者的开发难度。
UIGestureRecognizer
为了完成手势识别,必须借助于手势识别器—-UIGestureRecognizer。
利用UIGestureRecognizer,能轻松识别用户在某个view上面做的一些常见手势。
UIGestureRecognizer是一个抽象类,定义了所有手势的基本行为,使用它的子类才能处理具体的手势。
<code class="hljs scss has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-function" style="box-sizing: border-box;">UITapGestureRecognizer(敲击)</span> <span class="hljs-function" style="box-sizing: border-box;">UIPinchGestureRecognizer(捏合,用于缩放)</span> <span class="hljs-function" style="box-sizing: border-box;">UIPanGestureRecognizer(拖拽)</span> <span class="hljs-function" style="box-sizing: border-box;">UISwipeGestureRecognizer(轻扫)</span> <span class="hljs-function" style="box-sizing: border-box;">UIRotationGestureRecognizer(旋转)</span> <span class="hljs-function" style="box-sizing: border-box;">UILongPressGestureRecognizer(长按)</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><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></ul>
UITapGestureRecognizer
每一个手势识别器的用法都差不多,比如UITapGestureRecognizer的使用步骤如下
创建手势识别器对象
<code class="hljs fix has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-attribute" style="box-sizing: border-box;">UITapGestureRecognizer *tap </span>=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;"> [[UITapGestureRecognizer alloc] init];</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
设置手势识别器对象的具体属性
// 连续敲击2次
<code class="hljs fix has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-attribute" style="box-sizing: border-box;">tap.numberOfTapsRequired </span>=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;"> 2;</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
// 需要2根手指一起敲击
<code class="hljs fix has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-attribute" style="box-sizing: border-box;">tap.numberOfTouchesRequired </span>=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;"> 2;</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
添加手势识别器到对应的view上
<code class="hljs ini has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 102, 102);">[self.iconView addGestureRecognizer:tap]</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; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
监听手势的触发
<code class="hljs ruby has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">[tap <span class="hljs-symbol" style="color: rgb(0, 102, 102); box-sizing: border-box;">addTarget:</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">self</span> <span class="hljs-symbol" style="color: rgb(0, 102, 102); box-sizing: border-box;">action:</span><span class="hljs-variable" style="color: rgb(102, 0, 102); box-sizing: border-box;">@selector</span>(<span class="hljs-symbol" style="color: rgb(0, 102, 102); box-sizing: border-box;">tapIconView:</span>)];</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>
手势识别的状态
<code class="hljs objectivec has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">typedef</span> NS_ENUM(<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">NSInteger</span>, UIGestureRecognizerState) {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 没有触摸事件发生,所有手势识别的默认状态</span>
UIGestureRecognizerStatePossible,
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 一个手势已经开始但尚未改变或者完成时</span>
UIGestureRecognizerStateBegan,
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 手势状态改变</span>
UIGestureRecognizerStateChanged,
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 手势完成</span>
UIGestureRecognizerStateEnded,
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 手势取消,恢复至Possible状态</span>
UIGestureRecognizerStateCancelled,
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 手势失败,恢复至Possible状态</span>
UIGestureRecognizerStateFailed,
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 识别到手势识别</span>
UIGestureRecognizerStateRecognized = UIGestureRecognizerStateEnded
};</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; 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; background-color: rgb(238, 238, 238);"><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></ul>
手势识别状态变化示意图:
ps:新建iOS交流学习群:304570962 可以加猫猫QQ:1764541256 或则微信znycat 让我们一起努力学习吧。
翟乃玉的博客
地址:http://blog.youkuaiyun.com/u013357243?viewmode=contents
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