[英]How do i make a UIScrollView scroll automatically at a certain speed?
I am using touchesBegan and touchesMoved to track a user's interaction, so I can see where the user has touched the screen. 我正在使用touchesBegan和touchesMoved来跟踪用户的交互,因此我可以看到用户触摸屏幕的位置。 What I want to do is when they take their finger to the last 20 pixels of the screen, have the UIScrollView scroll1 to scroll down.
我要做的是当他们将手指移至屏幕的最后20个像素时,让UIScrollView scroll1向下滚动。 But how do i define a speed?
但是如何定义速度? Surely a while statement would do it far too rapidly, and a UIView animation would move it to a certain place but only the once.
当然,while语句会做得太快,而UIView动画会将其移动到某个位置,但只能移动一次。
You can do this by the following code : 您可以通过以下代码执行此操作:
[UIScrollView beginAnimations:@"scrollAnimation" context:nil];
[UIScrollView setAnimationDuration:REQUIRED_ANIMATION_DURATION];
[scroll setContentOffset:CGPointMake(REQUIRED_DISTANCE_X, REQUIRED_DISTANCE_Y)];
[UIScrollView commitAnimations];
Just set the values of REQUIRED_ANIMATION_DURATION to whatever time interval you want. 只需将REQUIRED_ANIMATION_DURATION的值设置为所需的任何时间间隔即可。 A smaller time interval will mean faster speed.
时间间隔越短,速度越快。
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