IOS的处理touch事件处理(依照手指的移动移动一个圆,开发环境用的ios7,storyboard）

来源：互联网发布：c语言字符串转化为数字编辑：程序博客网时间：2024/05/21 08:37

先看下页面的效果图：

首先定义这个ball它有两个属性和两个方法：

@property(nonatomic) CGPoint location;

@property(nonatomic) CGFloat length;

-(CGPoint) getCenterPoint;

-(BOOL) isInTheBall:(CGPoint) point;

方法体是：

//找出ball的中心点-(CGPoint) getCenterPoint {        return CGPointMake((self.location.x+self.length/2), self.location.y+self.length/2);};//看点point是不是在ball的范围内-(BOOL) isInTheBall:(CGPoint) point{    CGPoint center = self.getCenterPoint;    float t = (point.x - center.x) * (point.x - center.x);    float y = (point.y - center.y) * (point.y - center.y);        float k = sqrtf(t+y);    if (k < self.length/2) {        return YES;    }else {        return NO;    }};

定义BallView继承UIView

@property(nonatomic) Ball* ball;@property(nonatomic) BOOL isTouch;  //表示手指在ball的范围内移动@property(nonatomic) CGPoint prePoint;  //手指在进入move事件之前的那个点- (id)initWithBall:(CGRect)frame aBall:(Ball*) ball; //初始化方法

初始化函数为:

- (id)initWithBall:(CGRect)frame aBall:(Ball*) ball{    self = [super initWithFrame:frame];    if (self) {        // Initialization code        self.ball = ball;    }    return self;}-(void)awakeFromNib{    self.backgroundColor = nil;    self.opaque = NO;}// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect{    // Drawing code    [super drawRect:rect];        CGContextRef contextRef = UIGraphicsGetCurrentContext();    [[UIColor whiteColor] set];        //rect是整个view    CGContextFillRect(contextRef, rect);        [[UIColor redColor] set];        //CGContextAddEllipseInRect不会填充圆圈的内部   // CGContextAddEllipseInRect(contextRef, CGRectMake(200.0f, 200.0f, 50.0f, 50.0f));    CGContextFillEllipseInRect(contextRef, CGRectMake(self.ball.location.x,self.ball.location.y,self.ball.length,self.ball.length));        CGContextStrokePath(contextRef);}

我们在viewController里初始化只要：

-(void) loadView{    [super loadView];    Ball* ball = [[Ball alloc] init];    ball.location = CGPointMake(200.0f, 100.0f);    ball.length = 80.0f;    BallView* view = [[BallView alloc] initWithBall:[UIScreen mainScreen].bounds aBall:ball];    [self.view addSubview:view];        }

然后在下面在BallView中进行事件处理

-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{    NSLog(@"touchesBegan");    //下面两句知道手指在屏幕上的点的信息    UITouch* touch = [touches anyObject];    CGPoint point = [touch locationInView:self];        if ([self.ball isInTheBall:point]) {        self.isTouch = YES;        self.prePoint = point;    }else{        self.isTouch = NO;    }    NSLog(@"x=%f,y=%f",point.x,point.y);}-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{     NSLog(@"touchesMoved");    if (self.isTouch) {                CGRect preRect = CGRectMake(self.ball.location.x, self.ball.location.y, self.ball.length, self.ball.length);        //先用之前的location绘制一遍        [self setNeedsDisplayInRect:preRect];                UITouch* touch = [touches anyObject];        CGPoint point = [touch locationInView:self];                //cx和cy是手指的偏移量，用他们可以计算出新的location        float cx = point.x - self.prePoint.x;        float cy = point.y - self.prePoint.y;                self.ball.location = CGPointMake(self.ball.location.x + cx, self.ball.location.y+cy);        CGRect newRect = CGRectMake(self.ball.location.x, self.ball.location.y, self.ball.length, self.ball.length);        //用新的location绘制一遍        [self setNeedsDisplayInRect:newRect];        self.prePoint = point;    }}-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{    NSLog(@"touchesEnded");    self.isTouch = NO;}

代码可以在http://download.csdn.net/detail/baidu_nod/7533317下载

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