I've implemented a UIPanGestureRecognizer in a UIView graph I have made, with the intent of moving it around in the frame of another UIView, which has the same dimensions. However when running it moves all over the frame of the ViewController view (the whole screen) and it not restricted to the smaller frame of its parent UIView I have set up. Here's some screen shots of the graph moving around:
Here's the code for the parent (container) UIView which houses the GraphView class I have made:
class GraphViewDynamic:UIView {
var graphView:GraphView?
init(frame: CGRect, _ backgroudColor:UIColor, _ delegate:GraphViewDelegate) {
super.init(frame:frame)
self.graphView = GraphView.init(frame: frame, backgroudColor, delegate)
self.addSubview(self.graphView!)
}
func graphData(dataSetName setNames: [String], _ lineColors:[UIColor], _ timeInterval:GraphViewTimeInterval) {
if let _ = graphView {
graphView?.graphData(dataSetName: setNames, lineColors, timeInterval)
}
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
and here's the code in my GraphView UIView for the pan gesture handler:
func handlePan(_ sender:UIPanGestureRecognizer) {
sender.view?.center = sender.location(in: sender.view?.superview)
}
Any ideas on how to restrict the panning to the specified frame of the parent UIView of my GraphView (which has the same dimensions)? Thanks for any help.
Related
I have drawer controller presenting menu in the iOS app.
This menu is toggled by pressing menu buttons (UIButton) available on each screen.
As you can see in the mock: menu buttons can have red dot showing that new content is available - for this case I simply have two images for menu button without dot and with it.
I thought about making custom UIControl with "global" property for this dot. Is it the right way?
class MenuButton : UIButton {
static var showNotificationDot : Bool = false
}
For example you could create subclass UIButton and add observer.
class MyButton: UIButton {
static let notificationKey = NSNotification.Name(rawValue: "MyButtonNotificationKey")
override init(frame: CGRect) {
super.init(frame: frame)
self.subcribeForChangingState()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
fileprivate func subcribeForChangingState() {
NotificationCenter.default.addObserver(forName: MyButton.notificationKey, object: nil, queue: nil) { notificaton in
if let state = notificaton.object as? Bool {
self.changeState(active: state)
}
}
}
fileprivate func changeState(active: Bool) {
//change ui of all instances
print(active)
}
deinit {
NotificationCenter.default.removeObserver(self)
}
}
And change UI from any place like this:
NotificationCenter.default.post(name: MyButton.notificationKey, object: true)
I have a drawing app. Inside my VC there are five imageViews with five colors in them. I want to be able to click on the imageView and change the stroke color. It can be easily done if I repeat myself in the viewcontroller by adding gesture Recognizers to each UIImageView and have their individual "selector" function. Such as
func redTapped() {}
func blueTapped() {}
However, I want to be able to make the code more clear by creating a custom class (ColorImageView.Swift) for these ImageViews so that when I assign the class to these buttons, they automatically gets the tap gesture and my VC automatically receives the information about which one is tapped. At the moment, I can get a "imagePressed" printed out for each image that gets assigned to my class. However, I have no way of distinguishing which one were pressed. Below are my code for ColorImageView.Swift
import Foundation
class ColorImageView: UIImageView {
private func initialize() {
let touchGesture = UITapGestureRecognizer(target: self, action: #selector(ColorImageView.imagePressed(_:)))
touchGesture.numberOfTapsRequired = 1
self.userInteractionEnabled = true
self.addGestureRecognizer(touchGesture)
}
override init(frame: CGRect) {
super.init(frame: frame)
initialize()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
initialize()
}
func imagePressed(gestureRecognizer: UITapGestureRecognizer) {
print("image pressed \(gestureRecognizer)")
}
}
My imageView names are red.png, green.png, blue.png...etc
Thanks
You can get the tag easily.It works fine.
func imagePressed(gestureRecognizer: UITapGestureRecognizer)
{
print("image pressed \(gestureRecognizer)")
let tappedImageVIew = gestureRecognizer.view as! UIImageView
print("image pressed \(tappedImageVIew.tag)")
}
I am having a problem getting the UITapGestureRecognizer in my custom UIView.to work properly. I Have created a view: CategoryViewButton which adds a UITapGestureRecognizer in the init:
class CategoryViewButton: UIView {
override init(frame: CGRect) {
super.init(frame: frame)
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(self.handleTap))
self.addGestureRecognizer(tapGesture)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func handleTap() {
print("Hello again")
}
}
This gesture recognizer works without issue when added directly in a View Controller. However, when I add a CategoryViewButton as a subview of another custom view, the gesture recognizer method does not get called. My subview:
class CategoryView: UIView, CategoryButtonDelegate {
var button : CategoryViewButton?
override init(frame: CGRect) {
super.init(frame: frame)
button = CategoryViewButton(frame: CGRect(x: 10, y: 0, width: 40, height: 25))
self.addSubview(button!)
self.bringSubview(toFront: button!)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
When I create a CategoryView in a View Controller, the handleTap() function is not being called. What am I missing?
For anyone curious, the issue was that the subview with gesture recognizer was outside the frame of the superview. This means even though the view was being drawn, the gestures were not detected
I am trying to draw on an image from the camera roll using the code from this tutorial. After selecting a photo from the camera roll, imageView is set to the photo. When the user presses the draw button, tempImageView is added over the photo, so the user can draw onto it. However, when I attempt to draw on the image, nothing happens. Why?
Code:
class EditViewController: UIViewController{
var tempImageView: DrawableView!
var imageView: UIImageView = UIImageView(image: UIImage(named: "ClearImage"))
func draw(sender: UIButton!) {
tempImageView = DrawableView(frame: imageView.bounds)
tempImageView.backgroundColor = UIColor.clearColor()
self.view.addSubview(tempImageView)
}
}
class DrawableView: UIView {
let path=UIBezierPath()
var previousPoint:CGPoint
var lineWidth:CGFloat=10.0
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override init(frame: CGRect) {
previousPoint=CGPoint.zero
super.init(frame: frame)
}
required init?(coder aDecoder: NSCoder) {
previousPoint=CGPoint.zero
super.init(coder: aDecoder)
let panGestureRecognizer=UIPanGestureRecognizer(target: self, action: "pan:")
panGestureRecognizer.maximumNumberOfTouches=1
self.addGestureRecognizer(panGestureRecognizer)
}
override func drawRect(rect: CGRect) {
// Drawing code
UIColor.greenColor().setStroke()
path.stroke()
path.lineWidth=lineWidth
}
func pan(panGestureRecognizer:UIPanGestureRecognizer)->Void
{
let currentPoint=panGestureRecognizer.locationInView(self)
let midPoint=self.midPoint(previousPoint, p1: currentPoint)
if panGestureRecognizer.state == .Began
{
path.moveToPoint(currentPoint)
}
else if panGestureRecognizer.state == .Changed
{
path.addQuadCurveToPoint(midPoint,controlPoint: previousPoint)
}
previousPoint=currentPoint
self.setNeedsDisplay()
}
func midPoint(p0:CGPoint,p1:CGPoint)->CGPoint
{
let x=(p0.x+p1.x)/2
let y=(p0.y+p1.y)/2
return CGPoint(x: x, y: y)
}
}
make sure that tempImageView.userIteractionEnabled = YES. by default this property for UIImageView is NO.
after put breakpoint to you gestureRecogniser method, see if it's being called.
I'm having a problem with the graphOrigin property in my UIView subclass. When I defined graphOrigin as a computed variable, it convert's the superview's center point to this view's center point and displays the graph in the center of the screen. This does not happen when the variable isn't computed. See code and screenshot for the working case:
class GraphX_YCoordinateView: UIView {
var graphOrigin: CGPoint {
return convertPoint(center, fromView: superview)
}
#IBInspectable var scale: CGFloat = 50 {
didSet {
setNeedsDisplay()
}
}
override func drawRect(rect: CGRect) {
// Draw X-Y axes in the view
let axesDrawer = AxesDrawer(contentScaleFactor: contentScaleFactor)
axesDrawer.drawAxesInRect(bounds, origin: graphOrigin, pointsPerUnit: scale)
}
}
AxesDrawer is a class that draws axes in the current view, here is the method signature for drawAxesInRect:
drawAxesInRect(bounds: CGRect, origin: CGPoint, pointsPerUnit: CGFloat)
And here is the code and screenshot for the case that doesn't work:
class GraphX_YCoordinateView: UIView {
var graphOrigin: CGPoint! {
didSet {
setNeedsDisplay()
}
}
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
graphOrigin = convertPoint(center, fromView: superview)
}
#IBInspectable var scale: CGFloat = 50 {
didSet {
setNeedsDisplay()
}
}
override func drawRect(rect: CGRect) {
// Draw X-Y axes
let axesDrawer = AxesDrawer(contentScaleFactor: contentScaleFactor)
axesDrawer.drawAxesInRect(bounds, origin: graphOrigin, pointsPerUnit: scale)
}
}
So literally all I changed was initializing the graphOrigin property in place and computing it in the initializer. I didn't touch the StoryBoard at all while editing this code.
I tried initializing the variable inline:
var graphOrigin = convertPoint(center, fromView: superview)
But this wasn't allowed because the implicit self is not initialized when properties are computed.
Can anyone explain why the superview's center seems to change location depending on how the variable is initialized?
This function
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
graphOrigin = convertPoint(center, fromView: superview)
}
means that you are loading view from xib, and at this time the view dimension is 600:600 (look at your xib). So that your graphOrigin = 300:300. This is why you see the second picture.
To fix that problem, you should compute the graphOrigin after the view finish layout in viewDidLayout.