iOS基础之触摸事件处理

　　现在的手机都是触屏的，当我们在手机上使用一个软件的时候，我们都需要去触摸它。在iOS中，一个UITouch对象表示一个触摸，一个UIEvent对象表示一个事件。事件对象中包含与当前多点触摸序列相对应的所有触摸对象，还可以提供与特定试图或窗口相关联的触摸对象。

　　触摸事件的处理方法：

@implementation TouchView
//触摸的三个时间阶段的方法
//开始
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    NSLog(@"%s %d",__FUNCTION__,__LINE__);
    self.backgroundColor = [UIColor colorWithRed:arc4random()%256/255.0 green:arc4random()%256/255.0 blue:arc4random()%256/255.0 alpha:1.0];
//    //记录屏幕的宽和高
//    CGFloat screenWidth = [[UIScreen mainScreen]bounds].size.width;
//    CGFloat screenHeight = [[UIScreen mainScreen]bounds].size.height;
//    int minX = (int)(self.frame.size.width/2);
//    int maxX = (int)(screenWidth - self.frame.size.width/2);
//    int minY = (int)(self.frame.size.height/2);
//    int maxY = (int)(screenHeight) - minY;
//    
//    CGPoint newCenter = CGPointMake(0, 0);
//    newCenter.x = arc4random() % (maxX - minX + 1) + minX;
//    newCenter.y = arc4random() % (maxY - minY + 1) + minY;
//    self.center = newCenter;
}
//移动
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
    NSLog(@"%s %d",__FUNCTION__,__LINE__);
    //获取触摸在屏幕上的手指对象
    UITouch *touch = [touches anyObject];
    //获取手指之前在屏幕上的位置
    CGPoint previousP = [touch previousLocationInView:self];
    //获取手指在现在屏幕上的位置
    CGPoint currentP = [touch locationInView:self];
    
    CGPoint newCenter = CGPointMake(0, 0);
    newCenter.x = self.center.x + (currentP.x - previousP.x);
    newCenter.y = self.center.y + (currentP.y - previousP.y);
    self.center = newCenter;
    
    self.backgroundColor = [UIColor colorWithRed:arc4random()%256/255.0 green:arc4random()%256/255.0 blue:arc4random()%256/255.0 alpha:1.0];
}
//结束
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{
    NSLog(@"%s %d",__FUNCTION__,__LINE__);
    
}
@end