Question

我正在尝试从我的MainClass类中调用TheTimer类中的函数。但是，在TheTimer类中有一个必需的init，当我尝试从TheTimer类调用Start函数时（我从MainClass类中调用它）它会抛出错误：在调用中缺少参数'coder'的参数

TheTimer类负责作为故事板一部分的UIView。

TheTimer：

class TheTimer: UIView {

var timeLabel: UILabel

required init?(coder aDecoder: NSCoder) {

 timeLabel = UILabel()
 super.init(coder: aDecoder)
 let viewWidth = self.frame.size.width
 let viewHeight = self.frame.size.height
 timeLabel.frame = CGRect(x: 0, y: 0, width: viewWidth, height: viewHeight)
 timeLabel.text = "0"
 timeLabel.font = UIFont(name: "Arial", size: 45)
 timeLabel.textAlignment = NSTextAlignment.center
 self.addSubview(timeLabel)
 }

//MARK: Properties
var time: Double = 0.000

var timer = Timer()

func Start() {
    timer = Timer.scheduledTimer(timeInterval: 0.001, target: self, selector: #selector(countUp), userInfo: nil, repeats: true)
}

@objc func countUp() {
    time += 0.001


}

MainClass Class

import UIKit

class MainClass: UIViewController {
//MARK: Properties

@IBOutlet weak var answerLabel: UILabel!


//MARK: Go

@IBAction func startAll(_ sender: UIButton) {
    TheTimer().Start() //Throws error 'Missing argument for parameter 'coder' in call'

}

}

Answer 1

在MainClass课程中，为TheTimer视图创建一个属性，之后将故事板中的TheTimer与此IBOutlet相关联。最后，请致电theTimer.Start()而不是TheTimer().Start()

import UIKit

class MainClass: UIViewController {
//MARK: Properties

@IBOutlet weak var answerLabel: UILabel!

@IBOutlet weak var theTimer: TheTimer!


//MARK: Go

@IBAction func startAll(_ sender: UIButton) {
    theTimer.Start() // It will work fine

}

Answer 2

您正在调用一个尚未编写的空init（）函数。你唯一的init是必需的init，你不匹配它的参数。我建议编写第二个init函数，其中包含所有初始化内容。

init() {

 timeLabel = UILabel()
 super.init()
 let viewWidth = self.frame.size.width
 let viewHeight = self.frame.size.height
 timeLabel.frame = CGRect(x: 0, y: 0, width: viewWidth, height: viewHeight)
 timeLabel.text = "0"
 timeLabel.font = UIFont(name: "Arial", size: 45)
 timeLabel.textAlignment = NSTextAlignment.center
 self.addSubview(timeLabel)
 }

然后

 TheTimer().Start()

Answer 3

Yasin是正确的，你必须创建另一个init。另外，您可以将代码分成单独的方法。我不明白，为什么你不需要它是一个UIView并且如果你不使用任何这些标签就有标签。

init() {
    timeLabel = UILabel()
    super.init(frame: .zero)
    setupView()
}

required init?(coder aDecoder: NSCoder) {
    timeLabel = UILabel()
    super.init(coder: aDecoder)
    setupView()
}

func setupView() {
    let viewWidth = self.frame.size.width
    let viewHeight = self.frame.size.height
    timeLabel.frame = CGRect(x: 0, y: 0, width: viewWidth, height: viewHeight)
    timeLabel.text = "0"
    timeLabel.font = UIFont(name: "Arial", size: 45)
    timeLabel.textAlignment = NSTextAlignment.center
    self.addSubview(timeLabel)
}

Answer 4

因为您提供了所需的初始化程序convenience initializer，所以默认init()已经消失。因此，TheTimer（）类没有awakeFromNib()。您的错误发生在TheTimer（）而不是Start（）。

有两种方法：

1。在init?(coder aDecoder: NSCoder)而不是awakeFromNib()中调用初始化代码。
从Interface Builder归档或nib加载视图后，将立即调用var timeLabel: UILabel 然后，您应该将var timeLabel: UILabel! or ?更改为init() { super.init(frame: CGRect.zero) // you need to give it a frame, right? // Your initialization code timeLabel = UILabel() let viewWidth = self.frame.size.width let viewHeight = self.frame.size.height timeLabel.frame = CGRect(x: 0, y: 0, width: viewWidth, height: viewHeight) timeLabel.text = "0" timeLabel.font = UIFont(name: "Arial", size: 45) timeLabel.textAlignment = NSTextAlignment.center self.addSubview(timeLabel) }，因为您没有在初始化程序中对其进行初始化。
2。自己编写初始化程序

12 Nov 2017 23:48:51,292 [DEBUG] (DefaultNamespaceHandlerResolver.java:128)  - Ignoring namespace handler [org.springframework.ejb.config.JeeNamespaceHandler]: handler class not found
java.lang.ClassNotFoundException: org.springframework.ejb.config.JeeNamespaceHandler
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at org.springframework.util.ClassUtils.forName(ClassUtils.java:229)
    at org.springframework.beans.factory.xml.DefaultNamespaceHandlerResolver.initHandlerMappings(DefaultNamespaceHandlerResolver.java:117)
    at ......................
    org.springframework.beans.factory.access.SingletonBeanFactoryLocator.useBeanFactory(SingletonBeanFactoryLocator.java:382)
    at com.xxx.pci.util.ServiceLocator.getApplicationContext(ServiceLocator.java:24)
    at com.xxx.pci.decrypt.Decrypt.<init>(Decrypt.java:48)
    at com.xxx.mapper.SProductApplicationLogMapper.mapRow(SProductApplicationLogMapper.java:17)
    at org.springframework.jdbc.core.RowMapperResultSetExtractor.extractData(RowMapperResultSetExtractor.java:92)
    at org.springframework.jdbc.core.JdbcTemplate$1QueryStatementCallback.doInStatement(JdbcTemplate.java:395)
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:343)
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:405)
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:413)
    at com.xxx.AwipDataBean.getAllProductApplications(AwipDataBean.java:44)
    at 

public class ServiceLocator {
    private static ApplicationContext applicationContext;

    protected ServiceLocator() {
    }

    public static ApplicationContext getApplicationContext() {
        if (applicationContext == null) {
            BeanFactoryLocator locator = ContextSingletonBeanFactoryLocator.getInstance("applicationContextDef.xml");
            BeanFactoryReference bfr = locator.useBeanFactory("applicationContext");
            BeanFactory factory = bfr.getFactory();
            applicationContext = (ApplicationContext) factory;
            //bfr.release();
        }
        return applicationContext;
    }

}

顺便说一下，你应该用小写命名一个函数 The Swift Programming Language (Swift 4): Initialization developer.apple.com

由于初始化，无法在另一个类中调用函数

4 个答案: