As described in this UICollectionViewFlowlayout, Step 1:
// Need to overflow our actual visible rect slightly to avoid flickering.
var visibleRect = CGRectInset(self.collectionView!.bounds, -100, -100)
var itemsInVisibleRectArray: NSArray = super.layoutAttributesForElementsInRect(visibleRect)!
var itemsIndexPathsInVisibleRectSet: NSSet = NSSet(array: itemsInVisibleRectArray.valueForKey("indexPath") as [AnyObject])
// Step 1: Remove any behaviours that are no longer visible.
var noLongerVisibleBehaviours = (self.dynamicAnimator.behaviors as NSArray).filteredArrayUsingPredicate(NSPredicate(block: {behaviour, bindings in
var currentlyVisible: Bool = itemsIndexPathsInVisibleRectSet.member((behaviour as UIAttachmentBehavior).items.first!.indexPath) != nil
return !currentlyVisible
}))
"Type of expression is ambiguous without more context" .. what should I do? I am really stuck :/
Thank you for any help I can get on this...
If anyone might just want to solve this problem, look here:
let visibleRect = CGRectInset(self.collectionView!.bounds, -100, -100)
let itemsInVisibleRect = super.layoutAttributesForElementsInRect(visibleRect)!
let indexPathsInVisibleRect = Set(itemsInVisibleRect.map({ (attribute) -> NSIndexPath in
return attribute.indexPath
}))
// Step 1: Remove any behaviours that are no longer visible.
let noLongerVisisbleBehaviors = self.dynamicAnimator.behaviors.filter { (eachBehavior) -> Bool in
var currentlyVisible = false
if let behavior = eachBehavior as? UIAttachmentBehavior, first = behavior.items.first as? UICollectionViewLayoutAttributes {
currentlyVisible = indexPathsInVisibleRect.contains(first.indexPath)
}
return !currentlyVisible
}
Thankfully, this has proven to be a truly a huge save for the day :}
Related
I am trying to find an efficient way to solve the find a missing number from an array. I implemented the following way it's O(n). Please write any codes that efficiently solves this, just for learning purpose.
func findMissingNo(arrA: [Int]) -> [Int] {
let firstIndex = arrA.first ?? 0
let lastIndex = arrA.last ?? 0
let rslt = Array(firstIndex...lastIndex)
let missingNoArray = rslt.filter{ !arrA.contains($0)}
return missingNoArray
}
findMissingNo(arrA: [11,12,14,15,16,18]) // Prints [13, 17] by looping 9 times
Quickly written and tested (in terms of times performances against your code, but not in term of possible edges cases/mistakes, for instance, if array is 0...10, it won't work, but I'll let you work on the edges cases, since I focused mainly on the main cases, cases which might be covered during an edit and the end of the question)
Your current code:
func findMissingNo(arrA: [Int]) -> [Int] {
let firstIndex = arrA.first ?? 0
let lastIndex = arrA.last ?? 0
let rslt = Array(firstIndex...lastIndex)
let missingNoArray = rslt.filter{ !arrA.contains($0)}
return missingNoArray
}
let numberArray = [11,12,14,15,18]
let missing1 = findMissingNo(arrA: numberArray)
print("Missing1: \(missing1)")
My attempt:
func findMissingNo2(arrA: [Int]) -> [Int] {
var missingNumbers: [Int] = []
guard arrA.count > 2 else { return missingNumbers }
for i in 0...arrA.count-2 {
var current = arrA[i]
let next = arrA[i+1]
if next != current + 1 {
current += 1
while current != next {
missingNumbers.append(current)
current += 1
}
}
}
return missingNumbers
}
let missing2 = findMissingNo2(arrA: numberArray)
print("Missing1: \(missing2)")
Creating a big batch:
var array = Array(0...1000)
for _ in 0...10 {
if let index = array.indices.randomElement() {
let value = array.remove(at: index)
print("removed: \(value)") //To check just in case that's the good value returned by the methods
}
}
Testing:
let date1 = Date()
for _ in 0...100 {
let missing = findMissingNo(arrA: array)
print(missing)
}
print(Date().timeIntervalSince(date1)) //18.617565035820007
let date2 = Date()
for _ in 0...100 {
let missing = findMissingNo2(arrA: array)
print(missing)
}
print(Date().timeIntervalSince(date2)) //0.09566605091094971
print("---End")
print("")
For the time, I got: 18.857954025268555 vs 0.09159696102142334, a big factor difference (~200 times).
Why is there such a big difference?
Because of
let missingNoArray = rslt.filter{ !arrA.contains($0)}
It means:
for each number in result, check if arrayA contains that number.
->
for each number in result, for each number in arrayA (with a stop condition, so it's not a full iteration, but "almost" in term of complexity) check if there is a match...
Here there is a "double" (which is in fact not double, but n?) iteration that you missed.
I tested first with bigger value (array from "0 to 100000"), but it was taking too much time, with that "low number of values", the difference can already be seen.
Instead, you could use a Set:
let missingNoArray = Array(Set(rslt).subtracting(Set(arrA))).sorted()
It's faster than you method in my tests, (double my solution (0.21 ~ 0.22) in time performances), but still much faster than yours.
I added the sorted(), which may or may not be important in your solution, but will add time consumption since Set aren't ordered.
For the edges cases (ie: [3], [3, 4], [3, 8])
guard arrA.count > 2 else { return missingNumbers }
==>
guard !arrA.isEmpty else { return [] }
guard arrA.count > 2 else {
if arrA[0] + 1 >= arrA[1] {
return []
} else {
return Array((arrA[0] + 1)...arrA[1]).dropLast() //Because last will be arrA[1] which is present)
}
}
I'm asking the Microblink care reader to look at a photo of a card, rather than using the camera:
lazy var blinkCardRecognizer: MBCBlinkCardRecognizer = {
return MBCBlinkCardRecognizer()
}()
lazy var recognizerCollection: MBCRecognizerCollection = {
blinkCardRecognizer.extractCvv = false
blinkCardRecognizer.extractIban = false
blinkCardRecognizer.extractExpiryDate = false
let recognizerList = [blinkCardRecognizer]
return MBCRecognizerCollection(recognizers: recognizerList)
}()
My class has declared these two delegates:
MBCBlinkCardOverlayViewControllerDelegate, MBCScanningRecognizerRunnerDelegate
I'm sure that I'm passing this function a correct UIImage, and I do get to the processImage call:
func prepareToReadImage(_ theImage: UIImage?) {
let recognizerRunner: MBCRecognizerRunner = MBCRecognizerRunner(recognizerCollection: recognizerCollection)
recognizerRunner.scanningRecognizerRunnerDelegate = self
var image: MBCImage? = nil
if let anImage = theImage {
image = MBCImage(uiImage: anImage)
}
image?.cameraFrame = true
image?.orientation = MBCProcessingOrientation.left
let _serialQueue = DispatchQueue(label: "com.microblink.DirectAPI-sample-swift")
_serialQueue.async(execute: {() -> Void in
recognizerRunner.processImage(image!)
})
}
But this callback is not being hit:
func recognizerRunner(_ recognizerRunner: MBCRecognizerRunner, didFinishScanningWith state: MBCRecognizerResultState) {
if state == .valid {
print (state)
}
}
Can you see why it isn't? Does it matter that I see the log warning You are using time-limited license key!?
From the presented code, I can see that the recognizerRunner and the prepareToReadImage methods have been entered correctly.
However, in the first block of code, where you're defining the recognizer and the recognizerCollection, I can see that the issue could be with the MBCRecognizerCollection since its parameter, recognizers, is of type [MBCRecognizer], and you're placing there [MBCBlinkCardRecognizer]. I can suggest this solution to see if it works:
blinkCardRecognizer = MBCBlinkCardRecognizer()
var recognizerList = [MBCRecognizer]()
let recognizerCollection: MBCRecognizerCollection = {
blinkCardRecognizer.extractCvv = false
blinkCardRecognizer.extractIban = false
blinkCardRecognizer.extractExpiryDate = false
recognizerList.append(blinkCardRecognizer!)
return MBCRecognizerCollection(recognizers: recognizerList)
}()
recognizerRunner = MBCRecognizerRunner(recognizerCollection: recognizerCollection)
The only difference is that I've previously defined the BlinkCardRecognizer and the RecognizerRunner, so that should not make any difference:
private var recognizerRunner: MBCRecognizerRunner?
private var blinkCardRecognizer: MBCBlinkCardRecognizer?
Just to add here, it does not matter if you see the You are using time-limited license key!, it is simply an indicator that you using a time-limited key and it should not affect the scanning process.
I'm developing a music sequencer with a standard piano roll type UI.
It was working well until I made some changes in the model side but it suddenly started to report EXC_BAD_ACCESS at (seemingly) unrelated part.
What's strange is all the necessary variables have their values properly and actually I can print values with po.
In my understanding, EXC_BAD_ACCESS happens when an object doesn't exist, so this seems quite strange.
My question is:
Is it common to EXC_BAD_ACCESS even the values are there?
If that's the case what is the possible situation to cause that?
Any suggestion is helpful. Thanks
[Below are the codes]
In my subclass of UICollectionViewLayout:
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
// note cells
let cv = self.collectionView as! YMPianoRollCollectionView;
let pianoRoll = cv.pianoRollViewController;
// Call the below func to get the indexes of the Note Objects included in the specified rect
let indexArray: Array<Int> = pianoRoll!.getNoteIndexes(inRect:rect, useOnlyStartTime: false);
var retArray : [UICollectionViewLayoutAttributes] = []
for i in indexArray {
if let _ = pianoRoll?.pattern.eventSequence[i] as? YMPatternEventNoteOn {
retArray.append( self.layoutAttributesForPatternEventInfo(i) )
}
}
return retArray
}
In my "piano roll" class which contains UICollectionView
func getNoteIndexes(inRect rect:CGRect, useOnlyStartTime: Bool) -> Array<Int> {
//
// Transform given values into musical values
//
let musicRange :YMMusicalValueRange = screenInfo.getMusicalRange(rect);
let startTime = musicRange.origin.time;
let endTime = musicRange.origin.time + musicRange.size.timeLength;
let lowNoteU = musicRange.origin.noteNumber;
let highNoteU = musicRange.origin.noteNumber + musicRange.size.numberOfNotes;
var retArray : [Int] = []
for i in 0..<pattern.eventSequence.count {
if let e = pattern.eventSequence[i] as? YMPatternEventNoteOn {
//
// Prepare ranges
//
let noteNo = e.noteNo; //<- App Crashes Here with BAD_ACCESS
let noteStTime = e.time;
let noteEnTime = e.time + e.duration;
let targetNoteRange = Range<Int>(uncheckedBounds: (lowNoteU, highNoteU));
let targetTimeRange = Range<Int64>(uncheckedBounds: (startTime, endTime))
let noteTimeRange = Range<Int64>(uncheckedBounds: (noteStTime, noteEnTime))
//
// Check the match
//
let noteMatches = targetNoteRange.contains(noteNo);
let timeMatches = useOnlyStartTime ? targetTimeRange.contains(noteStTime)
: targetTimeRange.overlaps(noteTimeRange)
if noteMatches && timeMatches {
retArray.append( i );
NSLog("XXX Found: note \(noteNo) at \(e.time)");
}
}
}
return retArray;
}
Error:- The object states when it crashed
EDIT
Here's the YMPatternEventNoteOn declaration
class YMPatternEvent : Codable, CustomDebugStringConvertible {
var time : YMSequenceTime = 0
// Some utility funcs follow
// ...
}
class YMPatternEventNoteOn : YMPatternEvent {
var noteNo : Int = 64
var velocity : Int = 127
var duration : YMSequenceTime = 480
var tempBendId : Int = 0;
var tempVibratoId : Int = 0;
var tempArpeggioId : Int = 0;
convenience init(time :YMSequenceTime, noteNo : Int, velocity: Int, duration: YMSequenceTime) {
self.init();
self.time = time;
self.noteNo = noteNo;
self.velocity = velocity;
self.duration = duration;
}
// Other methods follow
// ...
}
EDIT2
Note event is created by the user's action
//
// In YMPattern object
//
func insertNote(time:YMSequenceTime, noteNo:Int, velocity:Int, duration:YMSequenceTime) -> Int
{
let onEvent = YMPatternEventNoteOn(time: time, noteNo: noteNo, velocity: velocity, duration: duration);
let retIndex = insertEvent(onEvent);
return retIndex;
}
func insertEvent(_ event: YMPatternEvent) -> Int {
let atTime = event.time;
var retIndex : Int = 0;
if(eventSequence.count<1){
// If it's the first event just add it
eventSequence.append(event);
retIndex = 0;
} else {
// If any event already exists, insert with time order in consideration
var i : Int = 0;
while( atTime > eventSequence[i].time ){
i += 1;
if( i >= eventSequence.count ){
break;
}
}
retIndex = i;
eventSequence.insert(event, at: i)
}
}
//
// In pianoroll view controller
//
func actionButtonReleased(afterDragging: Bool) {
let values:YMMusicalValuePoint = screenInfo.getMusicalPosition(cursorPosition);
// insert new event with default velocity and duration
let _ = pattern.insertNote(time: values.time, noteNo: values.noteNumber, velocity: 127, duration: screenInfo.timeTicsPerDivision());
collectionView.reloadData();
}
I've solved it in a way.
By setting the optimization level to "Whole Module Optimization" it stopped reporting the error.
I don't know what is happening internally but if someone is having the same issue, this might work as a quick fix.
I created two UITextView. One for line numbers and one for editing. However I can't seem to get the former to display line count. Here's what I've written so far and I'm sure I've made a mistake, just unsure where.
var previousRect = CGRectZero
var lineArray = ["1"]
func textViewDidChange(textView: UITextView) {
let pos = editorView.endOfDocument
let currentRect = editorView.caretRectForPosition(pos)
if(currentRect.origin.y > previousRect.origin.y){
//new line reached, write your code
var i = 0
i += 1
lineArray.append("\(i)")
let numberOfLinesString = "\(lineArray)"
lineNumbering.text = "\(lineArray)\n"
}
previousRect = currentRect
}
I'm trying to add something like UIPopoverController into the barPlot with coreplot 1.5.1 and swift. Like this one Core Plot: How to present popover from a bar selected by the user
So we need to know the point where the selected bar is ,But looks like some functions are different, like plotAreaViewPointForPlotPoint. In 1.5.1, there are two parameters:
And I'm try to find the right way to use it but failed, here is my code:
func barPlot(plot: CPTBarPlot!, barWasSelectedAtRecordIndex idx: UInt, withEvent event: UIEvent!) {
// Remove all the annotations
graphView.hostedGraph.plotAreaFrame.plotArea.removeAllAnnotations()
// Setup a style for the annotation
let hitAnnotationTextStyle = CPTMutableTextStyle.textStyle() as! CPTMutableTextStyle
hitAnnotationTextStyle.color = CPTColor.whiteColor()
hitAnnotationTextStyle.fontSize = 12.0;
hitAnnotationTextStyle.fontName = FONT_HEITI;
// Determine point of symbol in plot coordinates
let anchorPoint = [Int(idx),0]
// Add annotation
// First make a string for the y value
let string = "\(idx),values is：\(mArray.objectAtIndex(Int(idx)))"
// Now add the annotation to the plot area
let textLayer = CPTTextLayer(text: string, style: hitAnnotationTextStyle)
// popview, DxPopover is something like UIPopover Controller in iPhone
var popView = DXPopover()
annotationLabel.text = string
var pointers = [NSDecimal](count: 2, repeatedValue: CPTDecimalFromUnsignedInteger(0))
pointers[0] = CPTDecimalFromUnsignedInteger(idx)
var plotPointer: UnsafeMutablePointer<NSDecimal> = UnsafeMutablePointer<NSDecimal>.alloc(pointers.count)
plotPointer.initializeFrom(pointers)
var popPoint = graphView.hostedGraph.defaultPlotSpace.plotAreaViewPointForPlotPoint(plotPointer, numberOfCoordinates: idx)
popView.showAtPoint(popPoint, popoverPostion: DXPopoverPosition.Down, withContentView: self.annotationView, inView: graphView)
// selectedBarAnnotation = CPTPlotSpaceAnnotation(plotSpace: graphView.hostedGraph.defaultPlotSpace, anchorPlotPoint: anchorPoint)
// selectedBarAnnotation!.contentLayer = textLayer
// selectedBarAnnotation!.displacement = CGPointMake(0.0, -15.0)
// graphView.hostedGraph.plotAreaFrame.plotArea.addAnnotation(selectedBarAnnotation)
}
And it will crush at this line:
var popPoint = graphView.hostedGraph.defaultPlotSpace.plotAreaViewPointForPlotPoint(plotPointer, numberOfCoordinates: idx)
SO, HOW CAN I GET THE RIGHT CGPOINT?
Thanks very much!
=================EDIT===================
I change my codes to this, and can get the right point, Thanks to #Bannings
var popView = DXPopover()
annotationLabel.text = string
var pointers = [NSDecimal](count: 2, repeatedValue: CPTDecimalFromUnsignedInteger(0))
let plotXvalue = self.numberForPlot(plot, field: UInt(CPTScatterPlotFieldX.value), recordIndex: idx)
pointers[0] = CPTDecimalFromFloat(plotXvalue.floatValue)
println("\(CPTDecimalFromUnsignedInteger(idx))")
let plotspace = graphView.hostedGraph.defaultPlotSpace
println("\(plotspace.numberOfCoordinates)")
var popPoint = plotspace.plotAreaViewPointForPlotPoint(&pointers, numberOfCoordinates: plotspace.numberOfCoordinates)
popView.showAtPoint(popPoint, popoverPostion: DXPopoverPosition.Down, withContentView: self.annotationView, inView: graphView)
Try this:
var popPoint = graphView.hostedGraph.defaultPlotSpace.plotAreaViewPointForPlotPoint(&pointers, numberOfCoordinates: idx)