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https://github.com/firebase/firebase-ios-sdk
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Gil
ac06a94ace
* Fix bash style issues * Exclude additional build output directories * Format swift files with scripts/style.sh * Reformat swift sources * Allow swiftformat 0.32.0 on travis
84 lines
2.6 KiB
Swift
84 lines
2.6 KiB
Swift
// Copyright 2017 Google
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import UIKit
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import FirebaseDatabase
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/// A class to demonstrate the Firebase Realtime Database API. This will show a number read
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/// from the Database and increase or decrease it based on the buttons pressed.
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class DatabaseViewController: UIViewController {
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private enum Counter: Int {
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case increment = 1
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case decrement = -1
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var intValue: Int {
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return rawValue
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}
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}
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// MARK: - Interface
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/// Label to display the current value.
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@IBOutlet var currentValue: UILabel!
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// MARK: - User Actions
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/// The increment button was hit.
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@IBAction func incrementButtonHit(_ sender: UIButton) { changeServerValue(with: .increment) }
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/// the decrement button was hit.
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@IBAction func decrementButton(_ sender: UIButton) { changeServerValue(with: .decrement) }
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// MARK: - Internal Helpers
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/// Update the number on the server by a particular value. Note: the number passed in should only
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/// be one above or below the current number.
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private func changeServerValue(with type: Counter) {
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let ref = Database.database().reference(withPath: Constants.databasePath)
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// Update the current value of the number.
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ref.runTransactionBlock { (currentData) -> TransactionResult in
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guard let value = currentData.value as? Int else {
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return TransactionResult.abort()
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}
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currentData.value = value + type.intValue
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return TransactionResult.success(withValue: currentData)
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}
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}
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// MARK: - View Controller Lifecycle
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override func viewDidLoad() {
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super.viewDidLoad()
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// Observe the current value, and update the UI every time it changes.
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let ref = Database.database().reference(withPath: Constants.databasePath)
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ref.observe(.value) { [weak self] snapshot in
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guard let value = snapshot.value as? Int else {
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print("Error grabbing value from Snapshot!")
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return
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}
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self?.currentValue.text = "\(value)"
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}
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}
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// MARK: - Constants
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private struct Constants {
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static let databasePath = "magicSyncingCounter"
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}
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}
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