我要评论ios中的事件分为三类：触摸事件、加速计事件、远程控制事件。只有继承了uiresponder的对象才能接收并处理事件，称之为“响应者对象”。uiapplication、uiviewcontroller、uiview都继承自uiresponder。uiresponder内部提供的方法来处理事件：
触摸事件：touchesbegan、touchesmoved、touchesended、touchescancelled
加速计事件：motionbegan、motionended、motioncancelled
远程控制事件：remotecontrolreceivedwithevent
uiveiw的触摸事件处理过程：
/**
* 当手指开始触摸view时调用
*
* @param touches <#touches description#>
* @param event <#event description#>
*/
- (void)touchesbegan:(nsset<uitouch *> *)touches withevent:(uievent *)event {
nslog(@"%s",__func__);
}
/**
* 当手指在view上移动时调用
*
* @param touches <#touches description#>
* @param event <#event description#>
*/
- (void)touchesmoved:(nsset<uitouch *> *)touches withevent:(uievent *)event {
nslog(@"%s",__func__);
}
/**
* 当手指离开view时调用
*
* @param touches <#touches description#>
* @param event <#event description#>
*/
- (void)touchesended:(nsset<uitouch *> *)touches withevent:(uievent *)event {
nslog(@"%s",__func__);
}
/**
* 当触摸事件被系统事件打断时调用
*
* @param touches <#touches description#>
* @param event <#event description#>
*/
- (void)touchescancelled:(nsset<uitouch *> *)touches withevent:(uievent *)event {
nslog(@"%s",__func__);
}
一次触摸动作必然会调用touchesbeagn、touchesmoved和touchesended这三个方法。
说到这几个触摸方法，首先要知道uitouch这个对象。当一根手指触摸屏幕时就会产生一个与之关联的uitouch对象，一根手指对应一个uitouch对象。这个对象里面保存着这次触摸的信息，比如触摸的位置，时间，阶段等，当手指移动时，系统会更新同一个uitouch对象。使其能一直保存该手指所在的触摸位置信息。当手指离开屏幕时，系统会销毁对应的uitouch对象。
@interface uitouch : nsobject @property(nonatomic,readonly) nstimeinterval timestamp; @property(nonatomic,readonly) uitouchphase phase; @property(nonatomic,readonly) nsuinteger tapcount; // touch down within a certain point within a certain amount of time // majorradius and majorradiustolerance are in points // the majorradius will be accurate +/- the majorradiustolerance @property(nonatomic,readonly) cgfloat majorradius ns_available_ios(8_0); @property(nonatomic,readonly) cgfloat majorradiustolerance ns_available_ios(8_0); @property(nullable,nonatomic,readonly,strong) uiwindow *window; @property(nullable,nonatomic,readonly,strong) uiview *view; @property(nullable,nonatomic,readonly,copy) nsarray <uigesturerecognizer *> *gesturerecognizers ns_available_ios(3_2); //获取当前位置 - (cgpoint)locationinview:(nullable uiview *)view; //获取上一个触摸点的位置 - (cgpoint)previouslocationinview:(nullable uiview *)view; // force of the touch, where 1.0 represents the force of an average touch @property(nonatomic,readonly) cgfloat force ns_available_ios(9_0); // maximum possible force with this input mechanism @property(nonatomic,readonly) cgfloat maximumpossibleforce ns_available_ios(9_0); @end
eg:让一个view随着手指的移动而移动
/**
* 当手指在view上移动时调用
*
* @param touches <#touches description#>
* @param event <#event description#>
*/
- (void)touchesmoved:(nsset<uitouch *> *)touches withevent:(uievent *)event {
nslog(@"%s",__func__);
//获取uitouch对象
uitouch *touch = [touches anyobject];
//获取当前点的位置
cgpoint curp = [touch locationinview:self];
//获取上一个点的位置
cgpoint prep = [touch previouslocationinview:self];
//计算x的偏移量
cgfloat offsetx = curp.x - prep.x;
//计算y的偏移量
cgfloat offsety = curp.y = prep.y;
//修改view的位置
self.transform = cgaffinetransformtranslate(self.transform, offsetx, offsety);
}
就是根据uitouch对象中保存的位置信息来实现的。
事件的产生和传递：
当触摸事件产生后，系统会将该事件添加到一个由uiapplication管理的事件队列中去。uiapplication会从队列中取出最前面的事件，发送给应用程序的主窗口的处理。主窗口会在视图层次结构中，找一个最合适的视图并调用touches方法来处理触摸事件。触摸事件的传递是从父控件传递到子控件。如果父控件不能接收到触摸事件，那么子控件就不可能 接收到触摸事件。
如何找到最合适的控件来处理事件？首先判断自己是否能接收触摸事件？触摸点是否在自己身上？从后往前遍历子控件，重复之前的两个步骤，如果没有符合条件的子控件，那么就自己最合适处理。
控件用hittest:withevent:方法来寻找最合适的view，用pointinside这个方法判断这个点在不在方法调用者即控件身上。
hittest方法的底层实现：
- (uiview *)hittest:(cgpoint)point withevent:(uievent *)event {
//判断当前控件是否能接收触摸事件
if (self.userinteractionenabled == no || self.hidden == yes || self.alpha <= 0.01) {
return nil;
}
//判断触摸点是否在当前控件上
if ([self pointinside:point withevent:event] == no) {
return nil;
}
//从后往前遍历自己的子控件
nsinteger count = self.subviews.count;
for (nsinteger i = count - 1; i >= 0; i--) {
uiview *childview = self.subviews[i];
//把当前控件上的坐标系转换成子控件上的坐标系
cgpoint childpoint = [self convertpoint:point toview:childview];
//递归调用hittest方法寻找最合适的view
uiview *fitview = [childview hittest:childpoint withevent:event];
if (fitview) {
return fitview;
}
}
//循环结束，没有比自己更合适的view，返回自己
return self;
}
然而使用touches方法监听触摸事件是有缺点的，比如要自定义view，所以ios3.2之后苹果推出了手势识别功能uigesturerecognizer。uigesturerecognizer是一个抽象类，它的子类才能处理具体的某个手势。
具体有以下几种手势：
//点按手势 // uitapgesturerecognizer *tap = [uitapgesturerecognizer alloc]initwithtarget:<#(nullable id)#> action:<#(nullable sel)#> //长按手势 默认是触发两次 // uilongpressgesturerecognizer *longp = [uilongpressgesturerecognizer alloc]initwithtarget:<#(nullable id)#> action:<#(nullable sel)#> //轻扫手势 默认方向是往右 // uiswipegesturerecognizer *swipe = [uiswipegesturerecognizer alloc]initwithtarget:<#(nullable id)#> action:<#(nullable sel)#> //旋转手势 // uirotationgesturerecognizer *rotation = [uirotationgesturerecognizer alloc]initwithtarget:<#(nullable id)#> action:<#(nullable sel)#> //捏合手势 // uipinchgesturerecognizer *pinch = [uipinchgesturerecognizer alloc]initwithtarget:<#(nullable id)#> action:<#(nullable sel)#> //拖拽手势 // uipangesturerecognizer *pan = [uipangesturerecognizer alloc]initwithtarget:<#(nullable id)#> action:<#(nullable sel)#>
实际运用：
@interface viewcontroller ()<uigesturerecognizerdelegate>
@property (weak, nonatomic) iboutlet uiimageview *imageview;
@end
@implementation viewcontroller
- (void)viewdidload {
[super viewdidload];
[self setuppinch];
[self setuprotation];
[self setuppan];
}
#pragma mark - 手势代理方法
// 是否允许开始触发手势
//- (bool)gesturerecognizershouldbegin:(uigesturerecognizer *)gesturerecognizer
//{
// return no;
//}
// 是否允许同时支持多个手势，默认是不支持多个手势
// 返回yes表示支持多个手势
- (bool)gesturerecognizer:(uigesturerecognizer *)gesturerecognizer shouldrecognizesimultaneouslywithgesturerecognizer:(uigesturerecognizer *)othergesturerecognizer
{
return yes;
}
// 是否允许接收手指的触摸点
//- (bool)gesturerecognizer:(uigesturerecognizer *)gesturerecognizer shouldreceivetouch:(uitouch *)touch{
// // 获取当前的触摸点
// cgpoint curp = [touch locationinview:self.imageview];
//
// if (curp.x < self.imageview.bounds.size.width * 0.5) {
// return no;
// }else{
// return yes;
// }
//}
#pragma mark - 点按手势
- (void)setuptap
{
// 创建点按手势
uitapgesturerecognizer *tap = [[uitapgesturerecognizer alloc] initwithtarget:self action:@selector(tap:)];
tap.delegate = self;
[_imageview addgesturerecognizer:tap];
}
- (void)tap:(uitapgesturerecognizer *)tap
{
nslog(@"%s",__func__);
}
#pragma mark - 长按手势
// 默认会触发两次
- (void)setuplongpress
{
uilongpressgesturerecognizer *longpress = [[uilongpressgesturerecognizer alloc] initwithtarget:self action:@selector(longpress:)];
[self.imageview addgesturerecognizer:longpress];
}
- (void)longpress:(uilongpressgesturerecognizer *)longpress
{
if (longpress.state == uigesturerecognizerstatebegan) {
nslog(@"%s",__func__);
}
}
#pragma mark - 轻扫
- (void)setupswipe
{
// 默认轻扫的方向是往右
uiswipegesturerecognizer *swipe = [[uiswipegesturerecognizer alloc] initwithtarget:self action:@selector(swipe)];
swipe.direction = uiswipegesturerecognizerdirectionup;
[self.imageview addgesturerecognizer:swipe];
// 如果以后想要一个控件支持多个方向的轻扫，必须创建多个轻扫手势，一个轻扫手势只支持一个方向
// 默认轻扫的方向是往右
uiswipegesturerecognizer *swipedown = [[uiswipegesturerecognizer alloc] initwithtarget:self action:@selector(swipe)];
swipedown.direction = uiswipegesturerecognizerdirectiondown;
[self.imageview addgesturerecognizer:swipedown];
}
- (void)swipe
{
nslog(@"%s",__func__);
}
#pragma mark - 旋转手势
- (void)setuprotation
{
uirotationgesturerecognizer *rotation = [[uirotationgesturerecognizer alloc] initwithtarget:self action:@selector(rotation:)];
rotation.delegate = self;
[self.imageview addgesturerecognizer:rotation];
}
// 默认传递的旋转的角度都是相对于最开始的位置
- (void)rotation:(uirotationgesturerecognizer *)rotation
{
self.imageview.transform = cgaffinetransformrotate(self.imageview.transform, rotation.rotation);
// 复位
rotation.rotation = 0;
// 获取手势旋转的角度
nslog(@"%f",rotation.rotation);
}
#pragma mark - 捏合
- (void)setuppinch
{
uipinchgesturerecognizer *pinch = [[uipinchgesturerecognizer alloc] initwithtarget:self action:@selector(pinch:)];
pinch.delegate = self;
[self.imageview addgesturerecognizer:pinch];
}
- (void)pinch:(uipinchgesturerecognizer *)pinch
{
self.imageview.transform = cgaffinetransformscale(self.imageview.transform, pinch.scale, pinch.scale);
// 复位
pinch.scale = 1;
}
#pragma mark - 拖拽
- (void)setuppan
{
uipangesturerecognizer *pan = [[uipangesturerecognizer alloc] initwithtarget:self action:@selector(pan:)];
[self.imageview addgesturerecognizer:pan];
}
- (void)pan:(uipangesturerecognizer *)pan
{
// 获取手势的触摸点
// cgpoint curp = [pan locationinview:self.imageview];
// 移动视图
// 获取手势的移动，也是相对于最开始的位置
cgpoint transp = [pan translationinview:self.imageview];
self.imageview.transform = cgaffinetransformtranslate(self.imageview.transform, transp.x, transp.y);
// 复位
[pan settranslation:cgpointzero inview:self.imageview];
// nslog(@"%@",nsstringfromcgpoint(curp));
}
@end
以上就是ios触摸事件以及手势的相关内容介绍，希望对大家学习ios程序设计有所帮助。
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