iPhone开发中touch的事件

原文地址：http://www.cnblogs.com/ydhliphonedev/archive/2011/09/05/2167184.html

在ViewController中重写touch的事件的方法体就可实现特定的touch功能(但这些touch事件会被加在之上的tableView或scrollView等屏蔽,希望知道解决方案的留下方法).

下面代码实现清扫事件

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

messageLabel.text =@"Touches Began"; //开始触摸的方法

[self updateLabelsFromTouches:touches];

}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event{

messageLabel.text =@"Touches Cancelled";//触摸取消的方法

[self updateLabelsFromTouches:touches];

}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

messageLabel.text =@"Touches Stopped.";//触摸结束的方法

[self updateLabelsFromTouches:touches];

}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {

messageLabel.text =@"Drag Detected";//触摸移动的方法

[self updateLabelsFromTouches:touches];

}

触摸－轻扫:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

UITouch *touch = [touches anyObject];

gestureStartPoint = [touch locationInView:self.view];//开始触摸

}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event

{

UITouch *touch = [touches anyObject];

CGPoint currentPosition = [touch locationInView:self.view];

CGFloat deltaX = fabsf(gestureStartPoint.x - currentPosition.x);

CGFloat deltaY = fabsf(gestureStartPoint.y - currentPosition.y);

if (deltaX >= kMinimumGestureLength && deltaY <=kMaximumVariance)　

{//kMinimumGestureLength 最小移动长度 kMaximumVariance 最大偏移长度

label.text =@"Horizontal swipe detected";//水平消除

[self performSelector:@selector(eraseText)

withObject:nil afterDelay:2];

}

elseif (deltaY >= kMinimumGestureLength &&

deltaX <= kMaximumVariance)

{

　　     label.text =@"Vertical swipe detected";//垂直消除

[self performSelector:@selector(eraseText) withObject:nil

afterDelay:2];

}

}

多次轻击判断:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch = [touches anyObject];//实例一个uitouch

NSUInteger tapCount = [touch tapCount]; //计算touch的tapCount次数
switch (tapCount)

{

case1:

[self singleTap];

break;

case2:

[self doubleTap];

break;

case3:

[self tripleTap];

break;

case4:

[self quadrupleTap];

break;

default:

break;

}

}

捏合操作：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{//开始触碰
if ([touches count] ==2)

{//检测是否为两个手指触点

NSArray *twoTouches = [touches allObjects];

UITouch *first = [twoTouches objectAtIndex:0];

UITouch *second = [twoTouches objectAtIndex:1];

initialDistance = distanceBetweenPoints([first locationInView:self.view],

[second locationInView:self.view]);

}

}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event

{//移动手指
if ([touches count] ==2)

{
NSArray *twoTouches = [touches allObjects];

UITouch *first = [twoTouches objectAtIndex:0];

UITouch *second = [twoTouches objectAtIndex:1];

CGFloat currentDistance = distanceBetweenPoints([first locationInView:self.view],

[second locationInView:self.view]);

if (initialDistance ==0)

initialDistance = currentDistance; //根据移动前后的坐标距离差检测是捏合的手势还是打开的手势
elseif (currentDistance - initialDistance > kMinimumPinchDelta)

    {//检测是否大于最小移动值kMinimumPinchDelta

label.text =@"Outward Pinch";

[self performSelector:@selector(eraseLabel)

withObject:nil

afterDelay:1.6f];

}

elseif (initialDistance - currentDistance > kMinimumPinchDelta)

    {

label.text =@"Inward Pinch";

[self performSelector:@selector(something)

withObject:nil

afterDelay:1.6f];

}

}

}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event

{//触碰结束

initialDistance =0;

}

自定义手势“√”：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{
UITouch *touch = [touches anyObject];

CGPoint point = [touch locationInView:self.view];

lastPreviousPoint = point;

lastCurrentPoint = point;

lineLengthSoFar =0.0f;

}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event

{

UITouch *touch = [touches anyObject];

CGPoint previousPoint = [touch previousLocationInView:self.view];

CGPoint currentPoint = [touch locationInView:self.view];

CGFloat angle = angleBetweenLines(lastPreviousPoint, //计算两条线之间的角度

lastCurrentPoint,

previousPoint,

currentPoint);

if (angle >= kMinimumCheckMarkAngle&& angle <= kMaximumCheckMarkAngle

&& lineLengthSoFar > kMinimumCheckMarkLength)

{//检测手势被承认的条件 kMinimumCheckMarkAngle 最小角度kMaximumCheckMarkAngle最大角度kMinimumCheckMarkLength 画线最小长度

label.text =@"Checkmark";

[self performSelector:@selector(something)

withObject:nil afterDelay:1.6];

}
lineLengthSoFar += distanceBetweenPoints(previousPoint, currentPoint);//lineLengthSoFar , lastPreviousPoint, lastCurrentPoint 重新赋值

lastPreviousPoint = previousPoint;

lastCurrentPoint = currentPoint;

}

这里用到一个判断两条直线的角度的方法 angleBetweenLines(CGPoint line1Start, CGPoint line1End, CGPoint line2Start, CGPointlin2End);

如何判断touch到子视图或离开视图

这是在ios开发中常见的功能。即，touch移动事件，是移动到当前视图的子视图中，还是移动到当前视图以外了。

办法是，继承UIView，覆盖touchesMoved方法：

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

UITouch *touch=[touches anyObject];

if (![self pointInside:[touch locationInView:self] withEvent:nil])

{

NSLog(@"touches moved outside the view");

}

else

　 {

UIView *hitView=[self hitTest:[[touches anyObject] locationInView:self] withEvent:nil];

if (hitView==self)

　　 {

NSLog(@"touches moved in the view");

}

　　 else

{

NSLog(@"touches moved in the subview");

}

}

}