RxSwift：当textfield获得焦点时升级模型状态

这就是你要找的东西.每当UITextField发送textFieldDidBeginEdiTing：delegate消息时,您都会获得一个Observable.然后将Observable映射到该文本字段的正确字符串.然后将所有这三个Observable组合成一个,其中最新事件来自最近调用该委托消息的文本字段.然后将该值绑定到工具提示的文本.

import UIKit
import RxSwift
import RxCocoa

class ViewController: UIViewController {
    let disposeBag = DisposeBag()

    @IBOutlet weak var tooltip: UILabel!
    @IBOutlet weak var textField1: UITextField!
    @IBOutlet weak var textField2: UITextField!
    @IBOutlet weak var textField3: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()

        let textField1Text = textField1.rx_controlEvent(.EdiTingDidBegin)
            .map { "text field 1 message" }

        let textField2Text = textField2.rx_controlEvent(.EdiTingDidBegin)
            .map { "text field 2 message" }

        let textField3Text = textField3.rx_controlEvent(.EdiTingDidBegin)
            .map { "text field 3 message" }

        Observable.of(textField1Text,textField2Text,textField3Text).merge()
            .bindTo(tooltip.rx_text)
            .addDisposableTo(disposeBag)
    }
}