iphone，实现拖拽到同一位置

嗨，应用中有拖拽选项，需要实现将对象拖拽到位置之后，在同一位置设置对象，但是我下面的代码实现不了，不知道怎么办？是在IOS6版本中的，谢谢大家们的帮助。

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
CGPoint touchPoint = [[touches anyObject] locationInView:self.view];
if (touchPoint.x > self.img1.frame.origin.x &&
    touchPoint.x < self.img1.frame.origin.x + self.img1.frame.size.width &&
    touchPoint.y > self.img1.frame.origin.y &&
    touchPoint.y < self.img1.frame.origin.y + self.img1.frame.size.height )
{
    self.img1.backgroundColor = self.img1.backgroundColor;

}
self.img1.frame = CGRectMake(self.homePosition.x, self.homePosition.y,
                                   self.img1.frame.size.width,
                                   self.img1.frame.size.height);
}

在.h文件：

CGPoint startPt;

在.m文件：

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    startPt = [[touches anyObject] locationInView:self.view];

}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
CGPoint touchPoint = [[touches anyObject] locationInView:self.view];
if (touchPoint.x > self.img1.frame.origin.x &&
    touchPoint.x < self.img1.frame.origin.x + self.img1.frame.size.width &&
    touchPoint.y > self.img1.frame.origin.y &&
    touchPoint.y < self.img1.frame.origin.y + self.img1.frame.size.height )
{
    self.img1.backgroundColor = self.img1.backgroundColor;

}

self.img1.frame = CGRectMake(startPt.x, startPt.y,
                                   self.img1.frame.size.width,
                                   self.img1.frame.size.height);
}