UIView类下拉列表与UIButtons - 委托/协议问题？ [英] UIView class for drop down list with UIButtons - delegate/protocol issue?
问题描述
我想在ViewController中创建一个自定义下拉列表。有5个下拉列表，每个列表将有4个选项。因为列表的数量，我决定做一个UIView有四个选择在UIButtons的形式为每个列表。现在我只是想得到一个;因此，以下代码是针对ONE下拉列表与FIVE选项（包括选择的一个，我将在下面进一步解释）。
基本上我想要的是一个按钮显示所选的值（或启动时的默认值），然后当你点击那个值，那么UIView包含4按钮（也称为下拉列表）显示在原始按钮的下方。当用户点击其中一个按钮时，我希望具有所选值的按钮具有被点击的按钮的标题。
我遇到以下问题：
-
能够将四个按钮的标题从ViewController传递到UIView，因为我想多次使用这个UIView具有不同的值的四个按钮的标题。我不知道如何传递值到UIView类。
-
当点击下拉列表中的一个选项（即UIButton） t计算如何将按钮的标题的值从UIView传递回UIViewController。我试图将标题设置为ViewController中的一个变量，但是没有工作（显示为nil）。
非常感谢你 - 我知道这是一个很长的问题，我真的不确定这是否
这里是我的代码为ViewController
。这是一个很好的方法来采取我想要做的，
var buttonsLeft：buttonsView = buttonsView（）//这是UIView子类
var time = UIButton.buttonWithType（UIButtonType.System）如！ UIButton
override func viewWillAppear（animated：Bool）{
//隐藏下拉列表
self.buttonsLeft.frame = CGRect（x：self.view。 boundswidth *（1/6） - 50，y：120，width：100，height：135）
self.buttonsLeft.hidden = true
//在启动时的默认值
self.time.frame = CGRectMake（self.view.bounds.width *（1/6） - 50，90，100，30）
self.time.setTitle 1 DAY，forState：UIControlState.Normal）
self.time.addTarget（self，action：showLeft，forControlEvents：UIControlEvents.TouchUpInside）
self.time.hidden = false
self .view.addSubview（self.time）
}
//此函数显示列表
func showLeft（）{
self.view.addSubview（self.buttonsLeft）
self.buttonsLeft.hidden = false
}
这里是UIView的代码buttonsView：
import UIKit
class buttonsView：UIView {
var option1 = UIButton（）
var option2 = UIButton（）
var option3 = UIButton（）
var option4 = UIButton（）
var buttons：Array< UIButton> = array（）
var title：String = String（）
override init（frame：CGRect）{
super.init框架）
self.buttons = [option1，option2，option3，option4]
self.option1.setTitle（1 DAY，forState：UIControlState.Normal）
self.option2.setTitle 1 MONTH，forState：UIControlState.Normal）
self.option3.setTitle（1 YEAR，forState：UIControlState.Normal）
self.option4.setTitle（LONGER，forState：UIControlState。正常）
var yStep = 35
for var i：Int = 0; i< 4; ++ i {
var totalY：CGFloat = CGFloat（i * yStep）
buttons [i] .frame = CGRectMake（0，totalY，100，30）
buttons [i] .addTarget （self，action：chosenOption：，forControlEvents：UIControlEvents.TouchUpInside）
buttons [i] .hidden = false
self.addSubview（buttons [i]）
}
}
func chosenOption（sender：UIButton）{
self.title = sender.titleLabel！.text！
MyView（）。parentTitle = sender.titleLabel！.text！ //我试图分配给视图控制器中的变量
}
需要init（coder aDecoder：NSCoder）{
fatalError（init未实施）
}
}
委派将帮助您将值传递给 UIViewController 。
以下是您可以在 swift中实现 委托的方式
步骤1：在 class 中声明协议，用于 code>数据。这里是 buttonsview 。
@objc protocol MyButtonDelegate {
可选的func didSelectButton（text：String）
}
步骤2： $ c> delegate 。这里是 buttonsview 。
class buttonsView：UIView {
var delegate：MyButtonDelegate？
[other stuf ......]
}
步骤3 ：现在使用委托将数据发送到UIViewController。
func chosenOption（sender：UIButton）{
delegate！.didSelectButton（text：sender.titleLabel！.text！）
}
步骤4：在接收类中采用协议。
class ViewController：UIViewController，MyButtonDelegate {
步骤5：在接收类中实现委托方法。
func didSelectButton（text：String）{
parentTitle =The Buttons title is+ text
}
步骤6：现在设置委托
override func viewDidLoad（）{
super.viewDidLoad（）
buttonsLeft.delegate = self
}
希望这有助于你。
I am trying to create a custom drop down list in a ViewController. There are going to be 5 drop down lists and each list will have 4 options. Because of the number of lists, I decided to make a UIView that has the four choices in the form of UIButtons for each of the lists. Right now I am just trying to get one down; therefore, the following code is for ONE drop down list with FIVE options (including the one selected, which I will explain further below).
Essentially what I want is to have a button showing the selected value (or a default value at launch) and then when you click on that value then the UIView that contains 4 buttons (aka the drop down list) is shown below the original button. When the user clicks on one of the buttons I want the the button with the selected value to have the title of the button that was clicked on.
I am having the following issues:
I want to be able to pass the titles of the four buttons from the ViewController to the UIView because I want to use this UIView multiple times with different values for the titles of the four buttons. I don't know how to pass values to a UIView class.
When a choice from the drop down list (ie a UIButton) is clicked I can't figure out how to pass the value of the title of the button from the UIView back to UIViewController. I tried setting the title to a variable in the ViewController but that didn't work (showed up as nil).
Thank you so much in advance - I know this is a long questions and I am really unsure if this is even a good approach to take for what I am trying to do but it made sense in my head.
Here is my code for the ViewController
var buttonsLeft: buttonsView = buttonsView() // this is the UIView subclass
var time = UIButton.buttonWithType(UIButtonType.System) as! UIButton
override func viewWillAppear(animated: Bool) {
//hidden drop down list
self.buttonsLeft.frame = CGRect(x: self.view.bounds.width*(1/6) - 50, y:120, width:100, height: 135)
self.buttonsLeft.hidden = true
//button with selection showing or the default value at launch
self.time.frame = CGRectMake(self.view.bounds.width * (1/6) - 50, 90, 100, 30)
self.time.setTitle("1 DAY", forState: UIControlState.Normal)
self.time.addTarget(self, action: "showLeft", forControlEvents: UIControlEvents.TouchUpInside)
self.time.hidden = false
self.view.addSubview(self.time)
}
//this function shows the list
func showLeft(){
self.view.addSubview(self.buttonsLeft)
self.buttonsLeft.hidden = false
}
Here is the code for the UIView buttonsView:
import UIKit
class buttonsView: UIView {
var option1 = UIButton()
var option2 = UIButton()
var option3 = UIButton()
var option4 = UIButton()
var buttons: Array<UIButton> = Array()
var title:String = String()
override init(frame: CGRect) {
super.init(frame: frame)
self.buttons = [option1, option2, option3, option4]
self.option1.setTitle("1 DAY", forState: UIControlState.Normal)
self.option2.setTitle("1 MONTH", forState: UIControlState.Normal)
self.option3.setTitle("1 YEAR", forState: UIControlState.Normal)
self.option4.setTitle("LONGER", forState: UIControlState.Normal)
var yStep = 35
for var i:Int = 0; i < 4; ++i {
var totalY:CGFloat = CGFloat(i*yStep)
buttons[i].frame = CGRectMake(0, totalY, 100, 30)
buttons[i].addTarget(self, action: "choseOption:", forControlEvents: UIControlEvents.TouchUpInside)
buttons[i].hidden = false
self.addSubview(buttons[i])
}
}
func choseOption(sender:UIButton){
self.title = sender.titleLabel!.text!
MyView().parentTitle = sender.titleLabel!.text! // my attempt at assigning to variable in View Controller
}
required init(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
Delegation will help you to pass value to UIViewController.
Here are the way you can implement delegate in swift.
Step 1 : Declare protocol in class which is used to sending data. here is buttonsview.
@objc protocol MyButtonDelegate{
optional func didSelectButton(text:String)
}
Step 2 : Now declare delegate in sending class. here is buttonsview.
class buttonsView: UIView {
var delegate:MyButtonDelegate?
[other stuf......]
}
Step 3: now use delegate to send data to 'UIViewController'.
func choseOption(sender:UIButton){
delegate!.didSelectButton(text: sender.titleLabel!.text!)
}
Step 4 : adopt protocol in receiving class.
class ViewController: UIViewController,MyButtonDelegate {
Step 5: implement delegate method in receiving class.
func didSelectButton(text: String) {
parentTitle = "The Buttons title is " + text
}
Step 6: now set delegate
override func viewDidLoad() {
super.viewDidLoad()
buttonsLeft.delegate = self
}
Hope this help you.
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