I have a scrollView with some UIViews as subviews that I drag around. The problem is that the subviews is rather small, and when dragging them, you can't see them because the finger is in the way.
How do I offset the view a little bit upwards while dragging?
Thanks
if (recognizer.state == UIGestureRecognizerStateChanged)
{
CGPoint translation = [recognizer translationInView:self];
draggingView.center = CGPointMake(draggingView.center.x + translation.x,
draggingView.center.y + translation.y);
[recognizer setTranslation:CGPointZero inView:self];
}
Try following code
CGPoint touchPoint = [recognizer locationInView:self];
try changing touchPoint
Related
-(void)move:(UIPanGestureRecognizer *)recognizer
{
UIGestureRecognizerState state = [recognizer state];
if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
{
CGPoint translation = [recognizer translationInView:recognizer.view];
[recognizer.view setTransform:CGAffineTransformTranslate(recognizer.view.transform, translation.x, translation.y)];
[recognizer setTranslation:CGPointZero inView:recognizer.view];
}
}
There are several methods you can use;
Firstly, you can add a transparent subview in your main view and assign the pan gesture to that subview. Hence, only the pan gesture on subview will be recognized, and you can translate your main view directly.
Like this:
UIGestureRecognizerState state = [recognizer state];
if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
{
CGPoint translation = [recognizer translationInView:self.panView];
[self.mainView setTransform:CGAffineTransformTranslate(self.mainView.transform, translation.x, translation.y)];
[recognizer setTranslation:CGPointZero inView:self.panView];
}
(I didn't make panView completely transparent for show purposes, you should use clearColor instead of setting alpha to 0.)
(And obviously, panView is a subview of mainView, hence when the mainView is translated, panView also is translated.)
Secondly, you can customize your UIPanGestureRecognizer to implement touchesBegan: and raise a flag (like shouldRecognizeNow and check in move:method) if you don't want the touch to be recognized when started in particular place. (You may want to check CGRectContainsPoint: method.)
I'm not going into details of that, here's a link for starting:
https://stackoverflow.com/a/19145354/3227743
So I have a view with an UITableView on which I am able to add some objects (they come from my nib: SelectPostIt.xib).
These objects are draggable and what I want to do later is, when I'll drag then drop the object on a row of the TableView , it will add the object into the good row etc.
So I thought about many solutions and the one who seems to me the best is to catch the last coordinates of where I dropped my finger (the rest of the problem is another story :') ).
Here's my question, do I need to add something in my method who handle the dragNdrop of my object to know where I dropped it?
Here's my method:
-(IBAction)handlePan:(UIPanGestureRecognizer *)recognizer{
CGPoint translation = [recognizer translationInView:self];
recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x, recognizer.view.center.y + translation.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:self]; }
Every help will be welcome, thanks in advance!
Check for the state property of UIGestureRecognizer, if its UIGestureRecognizerStateEnded that means your panning has been ended, so you can choose that point of location as drop point.
-(IBAction)handlePan:(UIPanGestureRecognizer *)recognizer{
CGPoint translation = [recognizer translationInView:self];
recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x, recognizer.view.center.y + translation.y);
if(recognizer.state == UIGestureRecognizerStateEnded){
// Just take the Coordintate
CGPoint centerPointOfView = [recognizer locationInView:self.view];
NSLog(#"X - %f, Y - %f",centerPointOfView.x,centerPointOfView.y);
}
[recognizer setTranslation:CGPointMake(0, 0) inView:self];
}
I make a UIView that is movable by the user on the screen, it is a round rectangle that is 40x40, and the screen that it is on has a nav bar at the top and right now it can be moved under the nav bar, and then it is gone and can't come back.
Is there a way to make it so that it can't be moved off the screen?
I make it moveable like this:
- (IBAction)handlePan:(UIPanGestureRecognizer *)recognizer;
- (IBAction)handlePan:(UIPanGestureRecognizer *)recognizer {
CGPoint translation = [recognizer translationInView:self.view];
recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x, recognizer.view.center.y + translation.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
}
So my question is how can I make it so it can be moved off the screen.
Thanks for the help.
I am using the locationInView to set the position of my bouton when the user release it. After release, I give the location stored before but in fact, my button is not going back to the correct position.
This my code:
- (IBAction)handlePan:(UIPanGestureRecognizer *)recognizer{
CGPoint translation = [recognizer translationInView:self.view];
recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,
recognizer.view.center.y + translation.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
static CGPoint startLocation;
if (recognizer.state == UIGestureRecognizerStateBegan) {
startLocation = [recognizer locationInView:self.view];
NSLog(#"Began: %d" #"-" #"%d", (int)startLocation.x , (int)startLocation.y);
}
if (recognizer.state == UIGestureRecognizerStateEnded)
{
NSLog(#"Ended Bef: %d" #"-" #"%d", (int)startLocation.x, (int)startLocation.y);
recognizer.view.center = CGPointMake(startLocation.x, startLocation.y);
startLocation = [recognizer locationInView:self.view];
NSLog(#"Ended Aft: %d" #"-" #"%d", (int)startLocation.x, (int)startLocation.y);
}
}
In fact, the instruction:
recognizer.view.center = CGPointMake(startLocation.x, startLocation.y);
give a wrong effect. Someone know why?
A couple of thoughts:
I'd suggest making sure you capture startLocation before you do any changing of the center.
You're using the location of the user's touch for startLocation. You really should initialize this with the center of the recognizer.view. It's exceedingly unlikely that the user started their gesture precisely in the center of the button. And as a result, you're unlikely to return back at the original location.
Somewhat unrelated, but:
You don't need to use CGMakePoint when resetting the center of recognizer.view in the UIGestureRecognizerStateEnded clause. You can use CGPointMake if you really want, but it's unnecessary. You can just use startLocation, if you want.
You might want to animate the returning of the view back to that startLocation. It's jarring to have it immediately go there.
As an aside, if you've saved startLocation, you don't need to continually reset the translation. Just use startLocation plus translation. Seems more clear to me, but clearly that's subjective.
I personally think NSStringFromCGPoint is very useful when logging CGPoint structures.
So, I'd suggest:
- (IBAction)handlePan:(UIPanGestureRecognizer *)recognizer
{
static CGPoint startLocation;
if (recognizer.state == UIGestureRecognizerStateBegan)
{
startLocation = recognizer.view.center;
NSLog(#"Began: %#", NSStringFromCGPoint(startLocation));
}
CGPoint translation = [recognizer translationInView:self.view];
recognizer.view.center = CGPointMake(startLocation.x + translation.x,
startLocation.y + translation.y);
if (recognizer.state == UIGestureRecognizerStateEnded)
{
NSLog(#"Ended Bef: %#", NSStringFromCGPoint(startLocation));
[UIView animateWithDuration:0.25
animations:^{
recognizer.view.center = startLocation;
}];
CGPoint finalLocation = [recognizer locationInView:self.view];
NSLog(#"Ended Aft: %#", NSStringFromCGPoint(finalLocation));
}
}
I have a UIView object that can be dragged around using UIPanGestureRecognizer, but I only want it to be able to move up 3/4 of the screen. I don't want to it be clipped, but to get to a certain point and not be able to be dragged any further. What I have so far allows it to only move on the Y axis (which is desired).
- (IBAction)panGesture:(UIPanGestureRecognizer *)recognizer
{
CGPoint translation = [recognizer translationInView:self.view];
recognizer.view.center = CGPointMake(recognizer.view.center.x,
recognizer.view.center.y + translation.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
}
Thanks for any help.
So just check whether the new Y coordinate would be too small. Don't change the view if it would be too small:
- (IBAction)panGesture:(UIPanGestureRecognizer *)recognizer
{
CGPoint translation = [recognizer translationInView:self.view];
[recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
CGPoint center = recognizer.view.center;
center.y += translation.y;
if (center.y < self.yMin)
return;
recognizer.view.center = center;
}
Its work fine for me.
CGPoint currentTouchPoint = [gesture translationInView:self.bottomView];
if (fabsf(currentTouchPoint.x) > fabsf(currentTouchPoint.y)) {
// avoid horizontal movement of pan geuture.
return;
}
thanks,
Naveen Shan
Implement the following gesture delegate and check your condition inside it. Returning YES or NO from this delegate will make the gesture active and inactive.
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch;