how to move a view from where you touch it on the view?

Esko2300 · May 2012

Ok what i have working are views the user can move about the screen. In my touches moved code i am moving the view about it center. Ultimately what i would want to do is be able to move the view at whichever point the user touches the view on. Any more details just ask but i think thats good enough

BrianSlick · May 2012

When it is first touched, make a note of how far away the touch is from the view center. When adjusting the center, include that adjustment in the calculation.

One of the WWDC videos from last year, I believe it focused on scroll views, shows an example.

Duncan C · May 2012

BrianSlick;434908 said:
When it is first touched, make a note of how far away the touch is from the view center. When adjusting the center, include that adjustment in the calculation.

One of the WWDC videos from last year, I believe it focused on scroll views, shows an example.

Or note the original center, and the original touch point for the touchesBegan. When the user drags their finger, move the view's center by the same offset.

Gesture recognizers make this easier. Do a search in "Touches" in the Xcode help system, and look under Sample code for an entry with that name. It is a sample project that shows exactly how to do this. Note that there are actually 2 versions of the project, one that uses touchesBegan/touchesMoved/touchesEnded, and one that uses a pan gesture recognizer. I suggest looking at the gesture recognizer version. The code is much cleaner and easier to maintain.

Esko2300 · May 2012

Well i already have code i am using in TouchesMoved ect. so imma try to stick with that. I checked the Touches app and the code using TouchesMOved only moves the view about the center and not the initial touch point. Ill give your ideas with what to do with the initial point and center of the object and if i can't figure it out ill go with the UIPanGesture method instead. Thanks to both of you

Esko2300 · June 2012

well i got it working heres the code to do it

in your touchesBegan method just take the offset of the view in relation to the point of touch and the center


if([t view] == moveableSlide || [t view] == insertionSlide){
        Slide *s = [t view] == moveableSlide ? moveableSlide:insertionSlide; 
        offset = CGPointMake([t locationInView:self].x - s.center.x,  [t locationInView:self].y - s.center.y);

Then in touches moved just set the center of the view to the touchLocation minus the center


s.center = CGPointMake([t locationInView:self].x - offset.x, [t locationInView:self].y - offset.y);

Duncan C · June 2012

Esko2300;437174 said:
well i got it working heres the code to do it

in your touchesBegan method just take the offset of the view in relation to the point of touch and the center
if([t view] == moveableSlide || [t view] == insertionSlide){
        Slide *s = [t view] == moveableSlide ? moveableSlide:insertionSlide; 
        offset = CGPointMake([t locationInView:self].x - s.center.x,  [t locationInView:self].y - s.center.y);
Then in touches moved just set the center of the view to the touchLocation minus the center
s.center = CGPointMake([t locationInView:self].x - offset.x, [t locationInView:self].y - offset.y);

Code in a release app would need range checking to provent the user from dragging the view completely off the screen.

Esko2300 · June 2012

Duncan C;437177 said:
Code in a release app would need range checking to provent the user from dragging the view completely off the screen.

Good point, my code does that already since if the user lifts their finger off the view the view automatically disappears but its good for whomever will read this to know they must remove the view somehow

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how to move a view from where you touch it on the view?

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