問題描述

對此找不到清晰而翔實的解釋.

Couldn't find a clear and informative explanation for this.

推薦答案

在一個主題上搜索了一段時間后我沒有找到一個清晰的解釋，即使在它的類參考中UIAlertController 參考

After searching a while on a subject I didn't find a clear explanation , even in it's class reference UIAlertController Reference

沒關系，但對我來說不夠清楚.

It is ok, but not clear enough for me.

所以在收集了一些和平之后，我決定做出自己的解釋(希望對你有幫助)

So after collecting some peaces I decided to make my own explanation (Hope it helps)

就這樣吧:

1. UIAlertView 如所指出的那樣被棄用:Swift 中的 UIAlertView
2. UIAlertController 應該在 iOS8+ 中使用所以要先創建一個，我們需要實例化它，Constructor(init) 獲取 3 個參數:

1. UIAlertView is deprecated as pointed out : UIAlertView in Swift
2. UIAlertController should be used in iOS8+ so to create one first we need to instantiate it, the Constructor(init) gets 3 parameters:

2.1 title:String -> 顯示在警報對話框頂部的大粗體文本

2.1 title:String -> big-bold text to display on the top of alert's dialog box

2.2 message:String -> 較小的文本(幾乎可以解釋它的自身)

2.2 message:String -> smaller text (pretty much explains it's self)

2.3 prefferedStyle:UIAlertControllerStyle -> 定義對話框樣式，大多數情況下:UIAlertControllerStyle.Alert

2.3 prefferedStyle:UIAlertControllerStyle -> define the dialog box style, in most cases: UIAlertControllerStyle.Alert

1. 現在要實際向用戶展示它，我們可以使用 showViewController 或 presentViewController 并將我們的警報作為參數傳遞

1. Now to actually show it to the user, we can use showViewController or presentViewController and pass our alert as parameter

要添加一些與用戶的交互，我們可以使用:

To add some interaction with a user we can use:

4.1UIAlertController.addAction 創建按鈕

4.2UIAlertController.addTextField 創建文本字段

編輯說明:以下代碼示例，已針對 swift 3 語法進行了更新

Edit note: code examples below, updated for swift 3 syntax

示例 1:簡單對話框

@IBAction func alert1(sender: UIButton) {
     //simple alert dialog
    let alert=UIAlertController(title: "Alert 1", message: "One has won", preferredStyle: UIAlertControllerStyle.alert);
    //show it
    show(alert, sender: self);
}

示例 2:帶有一個輸入 textField 的對話框 &兩個按鈕

Example 2: Dialog with one input textField & two buttons

@IBAction func alert2(sender: UIButton) {
    //Dialog with one input textField & two buttons
    let alert=UIAlertController(title: "Alert 2", message: "Two will win too", preferredStyle: UIAlertControllerStyle.alert);
    //default input textField (no configuration...)
    alert.addTextField(configurationHandler: nil);
    //no event handler (just close dialog box)
    alert.addAction(UIAlertAction(title: "No", style: UIAlertActionStyle.cancel, handler: nil));
    //event handler with closure
    alert.addAction(UIAlertAction(title: "Yes", style: UIAlertActionStyle.default, handler: {(action:UIAlertAction) in
        let fields = alert.textFields!;
        print("Yes we can: "+fields[0].text!);
    }));
    present(alert, animated: true, completion: nil);
}

示例 3:一個自定義輸入 textField &一鍵

Example 3: One customized input textField & one button

@IBAction func alert3(sender: UIButton) {
   // one input & one button
   let alert=UIAlertController(title: "Alert 3", message: "Three will set me free", preferredStyle: UIAlertControllerStyle.alert);

    //configured input textField
    var field:UITextField?;// operator ? because it's been initialized later
    alert.addTextField(configurationHandler:{(input:UITextField)in
        input.placeholder="I am displayed, when there is no value ;-)";
        input.clearButtonMode=UITextFieldViewMode.whileEditing;
        field=input;//assign to outside variable(for later reference)
    });
    //alert3 yesHandler -> defined in the same scope with alert, and passed as event handler later
    func yesHandler(actionTarget: UIAlertAction){
        print("YES -> !!");
        //print text from 'field' which refer to relevant input now
        print(field!.text!);//operator ! because it's Optional here
    }
    //event handler with predefined function
    alert.addAction(UIAlertAction(title: "Yes", style: UIAlertActionStyle.default, handler: yesHandler));

    present(alert, animated: true, completion: nil);
 }

希望有幫助，祝你好運 ;-)

這篇關于哪里可以找到關于 swift alert (UIAlertController) 的清晰解釋?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！