iPhone開發中touch的事件隨筆（附touch移動事件）

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

在ViewController中重寫touch的事件的方法體就可實現特定的touch功能(但這些touch事件會被加在之上的tableView或scrollView等屏蔽,希望知道解決方案的留下方法).

下面代碼實現清掃事件

 

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
 
 messageLabel.text =@"Touches Began"; //開始觸摸的方法

 [self updateLabelsFromTouches:touches];
 
 }
 
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event{
 
 messageLabel.text =@"Touches Cancelled";//觸摸取消的方法

 [self updateLabelsFromTouches:touches];
 
 }
 
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
 
 messageLabel.text =@"Touches Stopped.";//觸摸結束的方法

 [self updateLabelsFromTouches:touches];
 
 }
 
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
 
 messageLabel.text =@"Drag Detected";//觸摸移動的方法

 [self updateLabelsFromTouches:touches];
 
 }

觸摸－輕掃:

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

{



    UITouch *touch = [touches anyObject];



    gestureStartPoint = [touch locationInView:self.view];//開始觸摸


}


- (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 最小移動長度 kMaximumVariance 最大偏移長度


        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];



    }



}

多次輕擊判斷:

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject];//實例一個uitouch

 NSUInteger tapCount = [touch tapCount]; //計算touch的tapCount次數  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

{//開始觸碰
if ([touches count] ==2) 

   {//檢測是否為兩個手指觸點

        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

{//移動手指
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; //根據移動前后的坐標距離差檢測是捏合的手勢還是打開的手勢
elseif (currentDistance - initialDistance > kMinimumPinchDelta) 

        {//檢測是否大於最小移動值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

{//觸碰結束

    initialDistance =0;

}

 

自定義手勢“√”：

- (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, //計算兩條線之間的角度

                                      lastCurrentPoint, 

                                      previousPoint, 

                                      currentPoint);

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

        && lineLengthSoFar > kMinimumCheckMarkLength) 

    {//檢測手勢被承認的條件 kMinimumCheckMarkAngle 最小角度kMaximumCheckMarkAngle最大角度kMinimumCheckMarkLength 畫線最小長度

        label.text =@"Checkmark";

        [self performSelector:@selector(something)

                   withObject:nil afterDelay:1.6];

    }
    lineLengthSoFar += distanceBetweenPoints(previousPoint, currentPoint);//lineLengthSoFar , lastPreviousPoint, lastCurrentPoint 重新賦值

    lastPreviousPoint = previousPoint;

    lastCurrentPoint = currentPoint;

}

這里用到一個判斷兩條直線的角度的方法 angleBetweenLines(CGPoint line1Start, CGPoint line1End, CGPoint line2Start, CGPointlin2End);

如何判斷touch到子視圖或離開視圖

這是在ios開發中常見的功能。即，touch移動事件，是移動到當前視圖的子視圖中，還是移動到當前視圖以外了。

辦法是，繼承UIView，覆蓋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"); 
             } 
    } 
}