I use the following code to move the cursor position to 5 characters from the beginning of a UITextField:
txtView.selectedRange = NSMakeRange(5, 0);
Now, if I have a cursor at an arbitrary position as shown in the image below, how can I move the cursor up, down, left and right?
Left and right should be more or less easy. I guess the tricky part is top and bottom. I would try the following.
You can use caretRect method to find the current "frame" of the cursor:
if let cursorPosition = answerTextView.selectedTextRange?.start {
let caretPositionRect = answerTextView.caretRect(for: cursorPosition)
}
Then to go up or down, I would use that frame to calculate estimated position in UITextView coordinates using characterRange(at:) (or maybe closestPosition(to:)), e.g. for up:
let yMiddle = caretPositionRect.origin.y + (caretPositionRect.height / 2)
let lineHeight = answerTextView.font?.lineHeight ?? caretPositionRect.height // default to caretPositionRect.height
// x does not change
let estimatedUpPoint = CGPoint(x: caretPositionRect.origin.x, y: yMiddle - lineHeight)
if let newSelection = answerTextView.characterRange(at: estimatedUpPoint) {
// we have a new Range, lets just make sure it is not a selection
newSelection.end = newSelection.start
// and set it
answerTextView.selectedTextRange = newSelection
} else {
// I guess this happens if we go outside of the textView
}
I haven't really done it before, so take this just as a general direction that should work for you.
Documentation to the methods used is here.
Related
I want to control the position of the mouse by adding the offset value to the current position. But I have a problem getting the y of the current position. Why?
This is my code：
func moveTouch(offsetPosition: CGPoint) {
let cursortPosition = NSEvent.mouseLocation
let resultPosition = CGPoint(x: cursortPosition.x + offsetPosition.x, y: cursortPosition.y + offsetPosition.y)
CGDisplayMoveCursorToPoint(1, resultPosition)
let source = CGEventSource.init(stateID: .hidSystemState)
let eventDown = CGEvent(mouseEventSource: source, mouseType: .mouseMoved, mouseCursorPosition: resultPosition , mouseButton: .left)
eventDown?.post(tap: .cghidEventTap)
print("===> cursort:\(cursortPosition) result:\(resultPosition) position:\(offsetPosition)")
}
ok, I know! because Because the position obtained by NSEvent.mouseLocation is based on the lower left corner。 And setting the position of CGWarpMouseCursorPosition is based on the lower left corner
I'd like to display a UIImageView with some animation and i'm thinking i'd like for it to appear on the screen pixel by pixel moving left to right, line by line. A bit like a printer would print an image.
I haven't got a clue where to start with this.
I was thinking maybe overlay the UIImageView with another view that can use animation to become transparent, but how can I make it happen?
Well one idea is, we have one view on top of your image, covering it entirely. Let's call this view V. Move that view down by 1 point, so a line of your image is exposed. Then have another view on top of your image, covering it entirely again. Let's call this view H. Then move that view right by 1 point. Now one "pixel" (or rather, a 1x1 point grid) of your image is exposed.
We'll animate H to the right. When it reaches the end, we'll put it back where it started, move V and H down by 1 point, and repeat the process.
Here's something to get you started.
extension UIView {
/**
- Parameter seconds: the time for one line to reveal
*/
func scanReveal(seconds: Double) {
let colour = self.superview?.backgroundColor ?? UIColor.black
let v = UIView(frame: self.bounds)
v.backgroundColor = colour
self.addSubview(v)
let h = UIView(frame: self.bounds)
h.backgroundColor = colour
self.addSubview(h)
v.frame.origin.y += 1
// Animate h to the end.
// When it reaches the end, bring it back, move v and h down by 1 and repeat.
func move() {
UIView.animate(withDuration: seconds, animations: {
h.frame.origin.x = h.bounds.height
}) { _ in
h.frame.origin.x = 0
h.frame.origin.y += 1
v.frame.origin.y += 1
if v.frame.origin.y > self.bounds.height {
return
}
move()
}
}
move()
}
}
I have UICollectionView which I'm dragging from code (don't ask me why it's very long story:)).
And my code is working pretty well:
func move(prevPoint: CGPoint, curPoint: CGPoint) {
let xDiff = curPoint.x - prevPoint.x
let yDiff = curPoint.y - prevPoint.y
let xSign = xDiff == 0 ? 1 : (xDiff / abs(xDiff))
let ySign = yDiff == 0 ? 1 : (yDiff / abs(yDiff))
let x = max(min(abs(xDiff), maxPickerStep), minPickerStep) * -xSign * xMultiplier
let y = max(min(abs(yDiff), maxPickerStep), minPickerStep) * -ySign
let offset = CGPoint(x: collectionView.contentOffset.x + x, y: collectionView.contentOffset.y)
let cell = (collectionView.visibleCells.first as? ColorsCollectionViewCell)
let innerOffset = cell?.colorCollectionView.contentOffset ?? .zero
let inset = (cell?.colorCollectionView.contentInset.top ?? 0) * 2
let innerYContentOffset = min(max(innerOffset.y + y, -inset), (cell?.colorCollectionView.contentSize.height ?? 0) - inset)
cell?.colorCollectionView.contentOffset = CGPoint(x: innerOffset.x, y: innerYContentOffset)
collectionView.contentOffset = offset
}
But in addition to scrolling, I want to achieve the same effect as in UICollectionView when scrollView moves by inertia after user takes away finger. Thanks.
First thing first, I think that moving the scroll view manually is most certainly a thing I would avoid.
Probably there is something much simpler to fulfill the behavior you need.
So I highly suggest you, and any other reader, to not go further in the reading of this post and, instead, go ahead and try to solve the problem that guided you here in the first place.
You could also ask another question here on Stack Overflow to maybe get help to try to avoid you to manually update the scrollView position.
So if you are still reading, this article is probably the way to go with implementing something that really feels like a UIScrollView. Doing anything else will probably really look and feel awful.
Basically it consists of using UIKit Dynamics to control the inertia.
So you can create an object that conforms to UIDynamicItem (with a non-zero CGRect), and change its center instead of the scrollView contentOffset, than use a UIDynamicAnimator and its UIDynamicBehavior to set up the inertia and to connect the changes during the animation to the corresponding contentOffset in the scrollView using the UIDynamicBehavior's action block.
Assuming that you have an item that is a UIDynamicItem, and an animator that is a UIDynamicAnimator, the handling of the panGesture recognizer would look something like this:
func handlGestureRecognizer(panGesture: UIPanGestureRecognizer) {
switch panGesture.state {
case .began:
self.animator.removeAllBehaviors()
case .changed:
// Update scroll view position
break
case .ended:
var velocity = panGesture.velocity(in: panGesture.view!)
velocity.x = -velocity.x
velocity.y = -velocity.y
// You probably need to check for out of bound velocity too, and also put velocity.x to 0 if the scroll is only scrolling vertically
// This is done to just save the current content offset and then change it alongside the animation from this starting point
item.center = scrollView.contentOffset
let decelerationBehavior = UIDynamicItemBehavior(items: [item])
decelerationBehavior.addLinearVelocity(velocity, for: item)
decelerationBehavior.resistance = 2.0
decelerationBehavior.action = {
// Connect the item center to the scroll contentOffset. Probably something like this:
scrollView.contentOffset = item.center
}
self.animator.addBehavior(decelerationBehavior)
default:
break
}
}
You than just need to play up with the values of the behavior and be careful with the velocity you put into the behavior having extra care in looking at the edge cases (if you scroll over the min/max for example)
PS: After all I've written, I still believe you should strongly consider not doing this and, instead, go with the standard scrollView scrolling, avoiding manual updates.
You can try to play with decelerationRate and see if it satisfies your needs.
collectionView.decelerationRate = UIScrollView.DecelerationRate(rawValue: 1)
I am creating a simple app with ARKit in which I add some text to the scene to the tapped position:
#objc func tapped(sender: UITapGestureRecognizer){
let sceneView = sender.view as! ARSCNView
let tapLocation = sender.location(in: sceneView)
let hitTest = sceneView.hitTest(tapLocation, types: .featurePoint)
if !hitTest.isEmpty{
self.addTag(tag: "A", hitTestResult: hitTest.first!)
}
else{
print("no match")
}
}
func addTag(tag: String, hitTestResult: ARHitTestResult){
let tag = SCNText(string:tag, extrusionDepth: 0.1)
tag.font = UIFont(name: "Optima", size: 1)
tag.firstMaterial?.diffuse.contents = UIColor.red
let tagNode = SCNNode(geometry: tag)
let transform = hitTestResult.worldTransform
let thirdColumn = transform.columns.3
tagNode.position = SCNVector3(thirdColumn.x,thirdColumn.y - tagNode.boundingBox.max.y / 2,thirdColumn.z)
print("\(thirdColumn.x) \(thirdColumn.y) \(thirdColumn.z)")
self.sceneView.scene.rootNode.addChildNode(tagNode)
}
It works, but I have problem with the orientation of the text. When I add it with the camera's original position, the text orientation is ok, I can see the text frontwise (Sample 1). But when I turn camera to the left / right, and add the text by tapping, I can see the added text from the side (Sample 2).
Sample 1:
Sample 2:
I know there should be some simple trick to solve it, but as a beginner in this topic I could not find it so far.
You want the text to always face the camera? SCNBillboardConstraint is your friend:
tagNode.constraints = [SCNBillboardConstraint()]
Am I correct in saying that you want the text to face the camera when you tap (wherever you happen to be facing), but then remain stationary?
There are a number of ways of adjusting the orientation of any node. For this case I would suggest simply setting the eulerAngles of the text node to be equal to those of the camera, at the point in which you instantiate the text.
In your addTag() function you add:
let eulerAngles = self.sceneView.session.currentFrame?.camera.eulerAngles
tagNode.eulerAngles = SCNVector3(eulerAngles.x, eulerAngles.y, eulerAngles.z + .pi / 2)
The additional .pi / 2 is there to ensure the text is in the correct orientation, as the default with ARKit is for a landscape orientation and therefore the text comes out funny. This applies a rotation around the local z axis.
It's also plausible (and some may argue it's better) to use .localRotate() of the node, or to access its transform property, however I like the approach of manipulating both the position and eulerAngles directly.
Hope this helps.
EDIT: replaced Float(1.57) with .pi / 2.
So I'll give as much information about this project as I can right up front. Here is an image of a section of the storyboard that is relevant to the issue:
And here is the flow of the code:
1) A user plays the game. This scrambles up the emoji that are displayed and will eventually hide all of the emoji on the right side.
2) When someone wins the game, it calls
performSegue(withIdentifier: "ShowWinScreenSegue", sender: self)
Which will perform the segue the red arrow is pointing to. This segue is a modal segue, over current content, cross dissolve.
3) Stuff goes on here, and then I try to get back to the game screen so the user can play another game. Here is my current code for that
// self.delegate is the GameController that called the segue
// it's set somewhere else in the code so I can call these reset functions
GameController.gs = GameState()
guard let d = self.delegate else {
return
}
d.resetGameToMatchState()
dismiss(animated: true, completion: {
print("Modal dismiss completed")
GameController.gs = GameState()
self.delegate?.resetGameToMatchState()
})
So here's where the issue is. You can see that I have to call delegate?.resetGameToMatchState() twice for anything to actually happen. If I remove the top one, nothing happens when I call the second one and vice-versa. What makes this so annoying is that the user will see a weird jump where all the ui goes from the old state to the new state because it's updating so late and spastically.
What I've tried so far
So this whole issue has made me really confused on how the UI system works.
My first thought was that maybe the function is trying to update the UI in a thread that's executing too early for the UI thread. So I put the whole body of resetGameToMatchState in a DispatchQueue.main.async call. This didn't do anything.
Then I thought that it was working before because when the WinScreenSegue was being dismissed before (when it was a "show" segue) it was calling GameController's ViewDidAppear. I tried manually calling this function in the dismiss callback, but that didn't work either and feels really hacky.
And now I'm stuck :( Any help would be totally appreciated. Even if it's just a little info that can clear up how the UI system works.
Here is my resetGameToMatchState():
//reset all emoji labels
func resetGameToMatchState() {
DispatchQueue.main.async {
let tier = GameController.gs.tier
var i = 0
for emoji in self.currentEmojiLabels! {
emoji.frame = self.currentEmojiLabelInitFrames[i]
emoji.isHidden = false
emoji.transform = CGAffineTransform(scaleX: 1, y: 1);
i+=1
}
i=0
for emoji in self.goalEmojiLabels! {
emoji.frame = self.goalEmojiLabelInitFrames[i]
emoji.isHidden = false
emoji.transform = CGAffineTransform(scaleX: 1, y: 1);
i+=1
}
//match state
for i in 1...4 {
if GameController.gs.currentEmojis[i] == GameController.gs.goalEmojis[i] {
self.currentEmojiLabels?.findByTag(tag: i)?.isHidden = true
}
}
//reset highlight
let f = self.highlightBarInitFrame
let currentLabel = self.goalEmojiLabels?.findByTag(tag: tier)
let newSize = CGRect(x: f.origin.x, y: (currentLabel?.frame.origin.y)!, width: f.width, height: (currentLabel?.frame.height)! )
self.highlightBarImageView.frame = newSize
//update taps
self.updateTapUI()
//update goal and current emojis to show what the current goal/current selected emoji is
self.updateGoalEmojiLabels()
self.updateCurrentEmojiLabels()
}
}
UPDATE
So I just found this out. The only thing that isn't working when I try to reset the UI is resetting the right side emoji to their original positions. What I do is at the start of the app (in viewDidLoad) I run this:
for emoji in currentEmojiLabels! {
currentEmojiLabelInitFrames.append(emoji.frame)
}
This saves their original positions to be used later. I do this because I animate them to the side of the screen before hiding them.
Now when I want to reset their positions, I do this:
var i = 0
for emoji in self.currentEmojiLabels! {
emoji.frame = self.currentEmojiLabelInitFrames[i]
emoji.isHidden = false
emoji.transform = CGAffineTransform(scaleX: 1, y: 1);
i+=1
}
this should set them all to their original frame and scale, but it doesn't set the position correctly. It DOES reset the scale though. What's weird is that I can see a tiny bit of one of the emoji off to the left of the screen and when they animate, they animate from far off on the left. I'm trying to think of why the frames are so off...
UPDATE 2
So I tried changing the frame reset code to this:
emoji.frame = CGRect(x: 25, y: 25, width: 25, height: 25)
Which I thought should reset them correctly to the top left, but it STILL shoves them off to the left. This should prove that the currentEmojiLabelInitFrames are not the issue and that it has something to do with when I'm setting them. Maybe the constraints are getting reset or messed up?
Your first screen, GameController, should receive a viewWillAppear callback from UIKit when the modal WinScreenController is being dismissed.
So its resetGameToMatchState function could simply set a property to true, then your existing resetGameToMatchState could move into viewWillAppear, checking first if the property is being set.
var resetNeeded: Bool = false
func resetGameToMatchState() {
resetNeeded = true
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
// reset code here
}
TLDR; Reset an element's scale BEFORE resetting it's frame or else it will scale/position incorrectly
Finally figured this out. Here's a bit more background. When an emoji is animated off the screen, this is called:
UIView.animate(withDuration: 1.5, animations: {
let newFrame = self.profileButton.frame
prevLabel?.frame = newFrame
prevLabel?.transform = CGAffineTransform(scaleX: 0.1, y: 0.1);
}) { (finished) in
prevLabel?.isHidden = true
}
So this sets the frame to the top left of the screen and then scales it down. What I didn't realize is that when I want to reset the element, I NEED to set the scale back to normal before setting the frame. Here is the new reset code:
for emoji in self.currentEmojiLabels! {
emoji.transform = CGAffineTransform(scaleX: 1, y: 1) //this needs to be first
emoji.frame = self.currentEmojiLabelInitFrames[i] //this needs to be after the scale
emoji.isHidden = false
i+=1
}