Sliding across piano keys (swift/iOS) - ios

Question

I'm working on an app (piano) that has a series of buttons that each has a different mp3. The screen shows 12 buttons (piano keys) and I want the user to be able to play an individual sound or swipe across a couple to hear multiple. Just like a real piano. I've seen many apps do this but mine seems to have a problem when the user slides across multiple buttons quickly. At the same speed, other apps will play all the notes, but mine will skip a few. Thank you for any help! This will make all the difference in my app!
A couple quick notes about this code:
-I just have the bare bones here to save space
-I just showed 6 audio players, but you get the idea
-the locationInNote1...Note2...Note3 is just showing 6 here to save place, but you get the idea
-"note1" in the button action is a string that can be changed when the user selects different octaves to play from, but its just a #, so the audio files ultimately are 1.mp3, 2.mp3, etc.
-the button action playNote1 is the same as the other button actions so i didn't repeat them all there.
var audioPlayer = AVAudioPlayer()
var audioPlayer2 = AVAudioPlayer()
var audioPlayer3 = AVAudioPlayer()
var audioPlayer4 = AVAudioPlayer()
var audioPlayer5 = AVAudioPlayer()
var audioPlayer6 = AVAudioPlayer()
func playNote(for locationInView: CGPoint) {
let locationInNote1 = note1Button.convert(locationInView, from: view)
let locationInNote2 = note2Button.convert(locationInView, from: view)
let locationInNote3 = note3Button.convert(locationInView, from: view)
let locationInNote4 = note4Button.convert(locationInView, from: view)
let locationInNote5 = note5Button.convert(locationInView, from: view)
let locationInNote6 = note6Button.convert(locationInView, from: view)
if note1Button.point(inside: locationInButton1, with: nil) {
playNote1(self)
}
if note2Button.point(inside: locationInButton2, with: nil) {
playNote2(self)
}
if note3Button.point(inside: locationInButton3, with: nil) {
playNote3(self)
}
if note4Button.point(inside: locationInButton4, with: nil) {
playNote4(self)
}
if note5Button.point(inside: locationInButton5, with: nil) {
playNote5(self)
}
if note6Button.point(inside: locationInButton6, with: nil) {
playNote6(self)
}
}
#IBAction func playNote1(_ sender: Any) {
let note1mp3 = note1
if let path = Bundle.main.path(forResource: note1mp3, ofType: "mp3") {
let url = URL(fileURLWithPath: path)
do {
audioPlayer = try AVAudioPlayer(contentsOf: url)
audioPlayer.prepareToPlay()
audioPlayer.play()
}
catch {
print(error)
}
}
}
override func viewDidLoad() {
super.viewDidLoad()
let panGesture = UIPanGestureRecognizer(target: self, action: #selector(handlePan(_:)))
view.addGestureRecognizer(panGesture)

Answer 1

Here is a way to hopefully:
Improve your code
Make your code simpler
Fix the problem you're having
In this example, I'll just put 3 audio players.
I'll try to make it as straight forward as possible...
import UIKit
class MyViewController: UIViewController {
var audioPlayer = AVAudioPlayer()
var audioPlayer2 = AVAudioPlayer()
var audioPlayer3 = AVAudioPlayer()
#IBOutlet var notes: [UIButton]!
let references = [note1, note2, note3]
#IBAction func notePressed(_ sender: UIButton) {
play(note: notes.index(of: sender)! + 1)
}
func play(note: Int) {
let reference = references[note - 1]
if let path = Bundle.main.path(forResource: reference, ofType: "mp3") {
let url = URL(fileURLWithPath: path)
do {
audioPlayer = try AVAudioPlayer(contentsOf: url)
audioPlayer.prepareToPlay()
audioPlayer.play()
}
catch {
print(error)
}
}
}
}
Explanation
#IBOutlet var notes: [UIButton]!
This is an Outlet Collection of buttons. To make this, connect a button but select Outlet Collection instead of just Outlet. Make sure you connect each button in order (1, 2, 3), otherwise it will break!
let references = [note1, note2, note3]
This is an array of references to each of the note files. This is so that we only need one function to play a note.
#IBAction func notePressed(_ :sender:)
This function gets called by the buttons. For each button, connect the Touch Drag Enter (for sliding along notes) and Touch Down actions. You can add other ones if you want. The functions compares the sender and notes Outlet Collection to find out which note was pressed, then passes it to the func play(:note:) function.
func play(:note:)
This function takes the note number, and plays the corresponding file. It's almost identical to your original one, but instead of having a fixed note, it has one that is passed by the #IBAction func notePressed(_ :sender:) method.
I hope this is helpful, good luck!