Why does touchesBegan stop working when UIImageView in placed inside a UIScrollView?
UIView -> UIImageView
I know I have things somewha开发者_开发问答t working ok since I can tap on my UIImageView
and see an NSLog()
statement in my touchesBegan
method.
.
UIView -> UIScrollView -> UIImageView
I drag that same UIImageView
into a UIScrollView
and touchesBegan
no longer gets called when I tap on my UIImageView
. (I haven't changed anything else. All the same connections, methods, and code remains unchanged.)
Why does touchesBegan
no longer work? And what can I do to get it working again?
Add uitapgesture to get event
Code is
UITapGestureRecognizer *ges11=[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(Handeltap:)];
[imagename addGestureRecognizer:ges11];
Create one action name "Handeltap" U will get called there.
by default UIImageView
don't handle user gestures.
set UIImageView
instance's userInteractionEnabled
to YES
Have a look at the documentation for UIScrollView.
Because a scroll view has no scroll bars, it must know whether a touch signals an intent to scroll versus an intent to track a subview in the content. To make this determination, it temporarily intercepts a touch-down event by starting a timer and, before the timer fires, seeing if the touching finger makes any movement. If the timer fires without a significant change in position, the scroll view sends tracking events to the touched subview of the content view. If the user then drags their finger far enough before the timer elapses, the scroll view cancels any tracking in the subview and performs the scrolling itself. Subclasses can override the
touchesShouldBegin:withEvent:inContentView:
,pagingEnabled
, andtouchesShouldCancelInContentView:
methods (which are called by the scroll view) to affect how the scroll view handles scrolling gestures.
I'd also recommend reading the Scroll View Programming Guide.
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