仅当手指在UIImage上时才拖动UIImage

Question

我成功编码了一个可拖动的图像但是，如果你随机点击屏幕中的某个地方，它就会传送到那个点。我不想要那个！ 当手指放在图像上时，如何使图像只能拖动？ 这是我的代码：

-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [[event allTouches] anyObject];
    CGPoint location = [touch locationInView:touch.view];
    symbol1.center = location;
}
-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    [self touchesBegan:touches withEvent:event];
}