I've been trying to get this code to work but of no use!
So the interface has a few buttons with numerical numbers in them (like a calculator). The task is to get the numerical values (in string) by using currentTitle method, converting into double and appendig to a stack (operandStack).
I was able to get one value onto stack but after that, the button the does it greys out and I can't do anything more with it.
#IBAction func addOntoStack() {
operandStack.append(dispValueInDouble)
print("operandStack = \(operandStack)")
}
var dispValueInDouble:Double{
doubleLabel = NSNumberFormatter().numberFromString(label.text!)!.doubleValue
print("label: \(doubleLabel)")
return doubleLabel
}
Related
I am developing a IOS custom keyboard. I was wondering if there was a way to fetch the current text inside of the text field and how it would work.
For example, we can use textDocumentProxy.hasText() to see if the textfield has text inside but I want to know the exact string that is inside the textfield.
The closest things would be textDocumentProxy.documentContextBeforeInput and textDocumentProxy.documentContextAfterInput. These will respect sentences and such, which means if the value is a paragraph, you will only get the current sentence. Users have been known to retrieve the entire string by repositioning the cursor multiple times until everything is retrieved.
Of course, you generally do not have to worry about this if the field expects a single value like a username, email, id number, etc. Combining the values of both before and after input contexts should suffice.
Sample Code
For the single phrase value, you would do:
let value = (textDocumentProxy.documentContextBeforeInput ?? "") + (textDocumentProxy.documentContextAfterInput ?? "")
For values that might contain sentence ending punctuation, it will be a little more complicated as you need to run it on a separate thread. Because of this, and the fact that you have to move the input cursor to get the full text, the cursor will visibly move. It is also unknown whether this will be accepted into the AppStore (after all, Apple probably did not add an easy way to get the full text on purpose in order to prevent official custom keyboards from invading a user's privacy).
Note: the below code is based off of this Stack Overflow answer except modified for Swift, removed unnecessary sleeps, uses strings with no custom categories, and uses a more efficient movement process.
func foo() {
dispatch_async(dispatch_queue_create("com.example.test", DISPATCH_QUEUE_SERIAL)) { () -> Void in
let string = self.fullDocumentContext()
}
}
func fullDocumentContext() {
let textDocumentProxy = self.textDocumentProxy
var before = textDocumentProxy.documentContextBeforeInput
var completePriorString = "";
// Grab everything before the cursor
while (before != nil && !before!.isEmpty) {
completePriorString = before! + completePriorString
let length = before!.lengthOfBytesUsingEncoding(NSUTF8StringEncoding)
textDocumentProxy.adjustTextPositionByCharacterOffset(-length)
NSThread.sleepForTimeInterval(0.01)
before = textDocumentProxy.documentContextBeforeInput
}
// Move the cursor back to the original position
self.textDocumentProxy.adjustTextPositionByCharacterOffset(completePriorString.characters.count)
NSThread.sleepForTimeInterval(0.01)
var after = textDocumentProxy.documentContextAfterInput
var completeAfterString = "";
// Grab everything after the cursor
while (after != nil && !after!.isEmpty) {
completeAfterString += after!
let length = after!.lengthOfBytesUsingEncoding(NSUTF8StringEncoding)
textDocumentProxy.adjustTextPositionByCharacterOffset(length)
NSThread.sleepForTimeInterval(0.01)
after = textDocumentProxy.documentContextAfterInput
}
// Go back to the original cursor position
self.textDocumentProxy.adjustTextPositionByCharacterOffset(-(completeAfterString.characters.count))
let completeString = completePriorString + completeAfterString
print(completeString)
return completeString
}
Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 7 years ago.
Improve this question
In my application I have a "Play" button which creates two random numbers and creates a string for those numbers, which is then used to fill in the two UIImage holders for cards (cards 0-10 which are set in a Array). Then the two random numbers are added together.
There is an input field where the user can input their guess and then hit "Submit". If their answer is correct it will flash "Correct". If the answer is wrong, it will flash Try Again. My question is how can I get the total variable passed to the Submit so I can successfully create my if else statements?
So here is the end code to the Play button Action which works perfectly
let total = firstRandomNumber + secondRandomNumber
Here is the code for the Submit button which is giving me an error
#IBAction func submit(sender: UIButton) {
correct.hidden = (true)
tryagain.hidden = (true)
let guess = Double(text.text!)
if guess = total {
correct.hidden = (false)
}
The error I'm getting is "undefined variable total"
So the variables are not going to be PASSED to Submit() because that's the function the button calls. The button can careless about your two variables. Instead you'll want to have two Global variables (in this case the two random numbers) and request them in Submit. These are variables that was created outside any functions and are set when they need to be set. So lets see how you'd do that with your code:
// Two random numbers (global)
var a: Int?
var b: Int?
func generateRandomNumber() {
a = // assign a to the number generator value
b = // same as above
}
func submit() { // your button call
if let userGuess = text.text { // do if let instead of ! it's safer
let total = a + b
if userGuess == total { // our check remember == is different from =
correctView.hidden = false
} else { // if it's wrong show this view
tryAgainView.hidden = false
}
}
}
Obviously there's a bunch missing but you can get the main idea. Let me know if these anything I can answer about this method.
Hello I have a profilelbl variable as below which is a uibutton. I want the text of the button to be an input in my database (parse). But I couldn't figured it out. I tried lots of things but still getting error:
#IBOutlet weak var profileLbl: UIButton!
var notification = PFObject(className: "notifications")
notification["actionReceiverName"] = profilelbl.text /*not working*/
/* also tried
notification["actionReceiverName"] = sender.profilelbl.text
notification["actionReceiverName"] = profilelbl.title */
you can do it easy like that
if let button = profilelbl as? UIButton {
if let title = button.titleForState(.Normal) {
println(title)
notification["actionReceiverName"] = title
}
}
Using UI objects to save/load data is a very bad idea. Using user-visible strings programmatically is an even worse idea. #ÖzgürErsil answered the question you asked, but the better answer to your question is "Don't do that. Ever."
Here are 2 examples where your approach will fail:
If 6 months later you want to change your UI and rename your button,
you won't remember that the button title is used in code and your
code will break. To that you would have to alter your database to
use a different string value.
If you decide to localize your app for foreign
languages, the button titles will come up in the local language, and
your code will break. There is no clean way to fix this problem,
since each local language would use a different version of the
button title.
It would be better to put unique tag numbers on your buttons, then look up text strings using the tags and pass those strings to your database.
Say you have button tags starting at 100.
You'd use code like this:
let buttonStrings = ["button1", "button2", "button3"]
let baseButtonTag = 100;
#IBAction func handleButton(sender: UIButton)
{
let tag = sender.tag
if tag >= baseButtonTag && tag < baseButtonTag + buttonStrings.count
{
let index = sender.tag - baseButtonTag
let buttonString = buttonStrings[index];
//Now use buttonString with your database as desired.
}
}
I am making calculator in Swift. Stuck in backspace button. If user press wrong digit then backspace button would help to delete digit off the display.
Though I wrote dropLast function and works. It return appropriate result. How to use count method, don't understand the return type of count method.
#IBOutlet weak var display: UILabel!
#IBAction func backspace() {
//how to use count method to check collection of elements
//dropLast drop the last digit and display result
let dropedDigit = dropLast(display.text!)
display.text = dropedDigit
}
How about something like this:
private func dropLast(text: String) -> String {
let endIndex = advance(text.endIndex, -1)
return text.substringToIndex(endIndex)
}
It calculates the index where you want to make the cut (endIndex of text - 1) and then returns the substring to this index. This function should drop the last character.
I am not using count method here, but for you reference Swift 1.2 introduces count(<#x: T#>) method that calculates length of sets including Strings.
I know this thread is outdated, but I just went through the process of making this work, myself, in Swift 2.2, and figured I could help answer it.
#IBAction func delButton(sender: AnyObject) {
if display.text != nil {
var tempString = Array(display.text!.characters)
tempString.removeLast(1)
display.text = ""
for num in 0..<tempString.count {
display.text = display.text! + String(tempString[num])
}
}
}
Basically, we're checking to see that the display label has stuff in it, so we don't throw an error, and if so, making a variable in the scope of the function to hold the label's characters individually in a string. After that, we remove the last character from the array, clear out the label to ensure we aren't adding what's already there to our new values, then iterating through the updated array of characters and adding it to the label.
It's important to note that we are casting the values contained in the array as String, because they've been put into the array as character values, which operate differently than the string value the label is expecting.
Like I said, I know the thread is a little out of date, but I've been going through courses in Swift, and have discovered that while there is a plethora of information out there for Objective-C, there is perilously little information out there for how to do a lot of those things in Swift. Since the language is being updated repeatedly, I've noticed a growing divide between the two languages.
I have an issue with converting character type to String type. First of all, I have below extension of String for finding nth character within String.
extension String {
func characterAtIndex(index: Int) -> Character? {
var cur = 0
for char in self {
if cur == index {
return char
}
cur++
}
return nil
}
}
I get what I want with this class extension. However when I use that nth character for title of my custom UIButton, gives an error. My Uibutton Class is
class hareketliHarfler: UIButton {
init(frame: CGRect) {
super.init(frame: frame)
// Initialization code
}
func getLetter(letter:String!){
self.titleLabel.text = letter
}
}
The error show when i try to access "getLetter(letter:String)" function. Here is example of main view Controller codes:
var harfim = hareketliHarfler(frame: CGRectMake(100,100,100,100))
var str="This is my String"
var bufi=str.characterAtIndex(3)
harfim.getLetter(bufi as AnyObject) ****
In * section I try .getLetter(bufi), .getLetter(bufi as String) also I try to change parameter type of function. Look like: func getLetter(letter:Character!) or func getLetter(letter:AnyObject!)...etc
Didn't find a way. Need a help on that. Thank you
How about the simple
String(theCharacter)
Works in Swift 4 and Swift 5
Your problem is quite simple: your characterAtIndex function returns a Character, and self.titleLabel.text is a String. You can't convert between the two implicitly. The easiest way would be to turn the Character into a String using the String initialiser:
// ch will be Character? type.
if let ch = str.characterAtIndex(3) {
// Initialise a new String containing the single character 'ch'
harfim.getLetter(String(ch))
} else {
// str didn't have a third character.
}
Unlike other solutions, this is safe for unusual Unicode characters, and won't initialise a potentially large array or iterate the whole String just to get the third character.
Change this:
var bufi=str.characterAtIndex(3)
harfim.getLetter(bufi as AnyObject)
to this:
harfim.getLetter(String(Array(str)[3]))
So what happening here:
we create an array from our string. Array elements are symbols from original string. Such break down correctly tracks symbols that are presented with a sequences of two or more code points. E.g. emoji or flag as noted by #MartinR.
We access element at 4-th position.
Note that as we crate an array from initial string then performance wise is better to use this method only with short strings and avoid it in oft-repeated routines. But in your case it seems to be OK.
Can also use Character(text).isNumber if you want to get localised numbers.
Reference:
https://developer.apple.com/documentation/swift/character/3127015-isnumber