触发按钮以更改 swift3 xcode 8 ios 10 中 UITextView 中的文本

我是 xcode 的新手，一直在解决这个问题，因为在网上尝试了几个示例代码示例后，没有任何效果.

I'm new to xcode and am stuck on this problem, because after trying several sample code examples online, nothing works.

你能帮我找出问题所在吗?

Could you help me figure out what the problem is?

我的代码如下:

import UIKit

class ViewController: UIViewController {
    @IBOutlet weak var Writingboard: UITextView!
    @IBOutlet weak var Talkbutton: UIButton!

    @IBAction func TalkbuttonTapped(_ sender: AnyObject){
        Talkbutton.setTitle("Tap to Stop", for: .normal)
        Writingboard.text="talking"
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        //Talkbutton.isEnabled=true
        Writingboard.text="test the initializer"
    } 
}