我对iOS和Objective-C以及整个MVC范式都是新手，我一直坚持以下几点：
我有一个充当数据输入表单的视图，我想让用户选择多个产品。产品列在另一个具有UITableViewController的视图中，我已启用多个选项。
如何将数据从一个视图传输到另一个视图？我会将UITableView上的选择保存在一个数组中，但如何将其传递回上一个数据输入表单视图，以便在提交表单时将其与其他数据一起保存到核心数据？
我在网上冲浪，看到一些人在应用程序委托中声明了一个数组。我读了一些关于单态的东西，但我不明白这些是什么，我读了关于创建数据模型的东西。
正确的执行方式是什么？我将如何执行？
当前回答
雨燕5Matt Price的回答非常适合传递数据，但我我将在最新的Swift版本中重写它，因为我相信由于新的语法和方法/框架，正如最初的帖子在Objective-C中那样。
在视图控制器之间传递数据有多种选项。
使用导航控制器推送使用Segue使用代理使用通知查看器使用块
我将用最新的iOS框架在Swift中重写他的逻辑
通过导航控制器传递数据推送：从ViewControllerA到ViewControllerB
步骤1。在ViewControllerB中声明变量
var isSomethingEnabled = false
步骤2。在ViewControllerB的ViewDidLoad方法中打印变量
override func viewDidLoad() {
super.viewDidLoad()
// Print value received through segue, navigation push
print("Value of 'isSomethingEnabled' from ViewControllerA: ", isSomethingEnabled)
}
步骤3。在ViewControllerA中通过导航控制器时传递数据
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.isSomethingEnabled = true
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
以下是完整的代码：
视图控制器A
import UIKit
class ViewControllerA: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
// MARK: Passing data through navigation PushViewController
@IBAction func goToViewControllerB(_ sender: Any) {
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.isSomethingEnabled = true
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
}
}
视图控制器B
import UIKit
class ViewControllerB: UIViewController {
// MARK: - Variable for Passing Data through Navigation push
var isSomethingEnabled = false
override func viewDidLoad() {
super.viewDidLoad()
// Print value received through navigation push
print("Value of 'isSomethingEnabled' from ViewControllerA: ", isSomethingEnabled)
}
}
通过Segue传递数据：从ViewControllerA到ViewControllerB
步骤1。创建从ViewControllerA到ViewControllerB的Segue，并在Storyboard中提供Identifier=showDetailSegue，如下所示
步骤2。在ViewControllerB中声明一个名为isSomethingEnabled的可行值并打印其值。
步骤3。在ViewControllerA中，传递Segue时传递SomethingEnabled的值
以下是完整的代码：
视图控制器A
import UIKit
class ViewControllerA: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
// MARK: - - Passing Data through Segue - -
@IBAction func goToViewControllerBUsingSegue(_ sender: Any) {
performSegue(withIdentifier: "showDetailSegue", sender: nil)
}
// Segue Delegate Method
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "showDetailSegue") {
let controller = segue.destination as? ViewControllerB
controller?.isSomethingEnabled = true//passing data
}
}
}
视图控制器B
import UIKit
class ViewControllerB: UIViewController {
var isSomethingEnabled = false
override func viewDidLoad() {
super.viewDidLoad()
// Print value received through segue
print("Value of 'isSomethingEnabled' from ViewControllerA: ", isSomethingEnabled)
}
}
通过委托传递数据：从ViewControllerB到ViewControllerA
步骤1。在ViewControllerB文件中声明协议ViewControllerBDlegate，但在类之外
protocol ViewControllerBDelegate: NSObjectProtocol {
// Classes that adopt this protocol MUST define
// this method -- and hopefully do something in
// that definition.
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?)
}
步骤2。在ViewControllerB中声明委托变量实例
var delegate: ViewControllerBDelegate?
步骤3。在ViewControllerB的viewDidLoad方法中发送委托的数据
delegate?.addItemViewController(self, didFinishEnteringItem: "Data for ViewControllerA")
步骤4。确认ViewControllerB在ViewControllerA中保留
class ViewControllerA: UIViewController, ViewControllerBDelegate {
// to do
}
步骤5。确认将在ViewControllerA中实现委托
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.delegate = self//confirming delegate
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
步骤6。实现用于在ViewControllerA中接收数据的委托方法
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?) {
print("Value from ViewControllerB's Delegate", item!)
}
以下是完整的代码：
视图控制器A
import UIKit
class ViewControllerA: UIViewController, ViewControllerBDelegate {
override func viewDidLoad() {
super.viewDidLoad()
}
// Delegate method
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?) {
print("Value from ViewControllerB's Delegate", item!)
}
@IBAction func goToViewControllerForDelegate(_ sender: Any) {
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.delegate = self
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
}
}
视图控制器B
import UIKit
//Protocol decleare
protocol ViewControllerBDelegate: NSObjectProtocol {
// Classes that adopt this protocol MUST define
// this method -- and hopefully do something in
// that definition.
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?)
}
class ViewControllerB: UIViewController {
var delegate: ViewControllerBDelegate?
override func viewDidLoad() {
super.viewDidLoad()
// MARK: - - - - Set Data for Passing Data through Delegate - - - - - -
delegate?.addItemViewController(self, didFinishEnteringItem: "Data for ViewControllerA")
}
}
通过通知查看器传递数据：从ViewControllerB到ViewControllerA
步骤1。在ViewControllerB中的通知查看器中设置和发布数据
let objToBeSent = "Test Message from Notification"
NotificationCenter.default.post(name: Notification.Name("NotificationIdentifier"), object: objToBeSent)
步骤2。在ViewControllerA中添加通知查看器
NotificationCenter.default.addObserver(self, selector: #selector(self.methodOfReceivedNotification(notification:)), name: Notification.Name("NotificationIdentifier"), object: nil)
步骤3。在ViewControllerA中接收通知数据值
@objc func methodOfReceivedNotification(notification: Notification) {
print("Value of notification: ", notification.object ?? "")
}
以下是完整的代码：
视图控制器A
import UIKit
class ViewControllerA: UIViewController{
override func viewDidLoad() {
super.viewDidLoad()
// Add observer in controller(s) where you want to receive data
NotificationCenter.default.addObserver(self, selector: #selector(self.methodOfReceivedNotification(notification:)), name: Notification.Name("NotificationIdentifier"), object: nil)
}
// MARK: Method for receiving Data through Post Notification
@objc func methodOfReceivedNotification(notification: Notification) {
print("Value of notification: ", notification.object ?? "")
}
}
视图控制器B
import UIKit
class ViewControllerB: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// MARK:Set data for Passing Data through Post Notification
let objToBeSent = "Test Message from Notification"
NotificationCenter.default.post(name: Notification.Name("NotificationIdentifier"), object: objToBeSent)
}
}
通过块传递数据：从ViewControllerB到ViewControllerA
步骤1。在ViewControllerB中声明块
var authorizationCompletionBlock:((Bool)->())? = {_ in}
步骤2。在ViewControllerB中设置块中的数据
if authorizationCompletionBlock != nil
{
authorizationCompletionBlock!(true)
}
步骤3。在ViewControllerA中接收块数据
// Receiver Block
controller!.authorizationCompletionBlock = { isGranted in
print("Data received from Block is: ", isGranted)
}
以下是完整的代码：
视图控制器A
import UIKit
class ViewControllerA: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
// MARK:Method for receiving Data through Block
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "showDetailSegue") {
let controller = segue.destination as? ViewControllerB
controller?.isSomethingEnabled = true
// Receiver Block
controller!.authorizationCompletionBlock = { isGranted in
print("Data received from Block is: ", isGranted)
}
}
}
}
视图控制器B
import UIKit
class ViewControllerB: UIViewController {
// MARK: Variable for Passing Data through Block
var authorizationCompletionBlock:((Bool)->())? = {_ in}
override func viewDidLoad() {
super.viewDidLoad()
// MARK: Set data for Passing Data through Block
if authorizationCompletionBlock != nil
{
authorizationCompletionBlock!(true)
}
}
}
你可以在我的GitHub上找到完整的示例应用程序。如果你对此有任何疑问，请告诉我。
其他回答
我喜欢基于NSProxy的模型对象和模拟对象的想法，以便在用户选择的内容可以取消时提交或丢弃数据。
传递数据很容易，因为它是一个对象或两个对象，如果你有一个UINavigationController控制器，你可以将对模型的引用保存在内部，所有推送视图控制器都可以直接从导航控制器访问它。
雨燕5Matt Price的回答非常适合传递数据，但我我将在最新的Swift版本中重写它，因为我相信由于新的语法和方法/框架，正如最初的帖子在Objective-C中那样。
在视图控制器之间传递数据有多种选项。
使用导航控制器推送使用Segue使用代理使用通知查看器使用块
我将用最新的iOS框架在Swift中重写他的逻辑
通过导航控制器传递数据推送：从ViewControllerA到ViewControllerB
步骤1。在ViewControllerB中声明变量
var isSomethingEnabled = false
步骤2。在ViewControllerB的ViewDidLoad方法中打印变量
override func viewDidLoad() {
super.viewDidLoad()
// Print value received through segue, navigation push
print("Value of 'isSomethingEnabled' from ViewControllerA: ", isSomethingEnabled)
}
步骤3。在ViewControllerA中通过导航控制器时传递数据
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.isSomethingEnabled = true
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
以下是完整的代码：
视图控制器A
import UIKit
class ViewControllerA: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
// MARK: Passing data through navigation PushViewController
@IBAction func goToViewControllerB(_ sender: Any) {
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.isSomethingEnabled = true
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
}
}
视图控制器B
import UIKit
class ViewControllerB: UIViewController {
// MARK: - Variable for Passing Data through Navigation push
var isSomethingEnabled = false
override func viewDidLoad() {
super.viewDidLoad()
// Print value received through navigation push
print("Value of 'isSomethingEnabled' from ViewControllerA: ", isSomethingEnabled)
}
}
通过Segue传递数据：从ViewControllerA到ViewControllerB
步骤1。创建从ViewControllerA到ViewControllerB的Segue，并在Storyboard中提供Identifier=showDetailSegue，如下所示
步骤2。在ViewControllerB中声明一个名为isSomethingEnabled的可行值并打印其值。
步骤3。在ViewControllerA中，传递Segue时传递SomethingEnabled的值
以下是完整的代码：
视图控制器A
import UIKit
class ViewControllerA: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
// MARK: - - Passing Data through Segue - -
@IBAction func goToViewControllerBUsingSegue(_ sender: Any) {
performSegue(withIdentifier: "showDetailSegue", sender: nil)
}
// Segue Delegate Method
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "showDetailSegue") {
let controller = segue.destination as? ViewControllerB
controller?.isSomethingEnabled = true//passing data
}
}
}
视图控制器B
import UIKit
class ViewControllerB: UIViewController {
var isSomethingEnabled = false
override func viewDidLoad() {
super.viewDidLoad()
// Print value received through segue
print("Value of 'isSomethingEnabled' from ViewControllerA: ", isSomethingEnabled)
}
}
通过委托传递数据：从ViewControllerB到ViewControllerA
步骤1。在ViewControllerB文件中声明协议ViewControllerBDlegate，但在类之外
protocol ViewControllerBDelegate: NSObjectProtocol {
// Classes that adopt this protocol MUST define
// this method -- and hopefully do something in
// that definition.
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?)
}
步骤2。在ViewControllerB中声明委托变量实例
var delegate: ViewControllerBDelegate?
步骤3。在ViewControllerB的viewDidLoad方法中发送委托的数据
delegate?.addItemViewController(self, didFinishEnteringItem: "Data for ViewControllerA")
步骤4。确认ViewControllerB在ViewControllerA中保留
class ViewControllerA: UIViewController, ViewControllerBDelegate {
// to do
}
步骤5。确认将在ViewControllerA中实现委托
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.delegate = self//confirming delegate
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
步骤6。实现用于在ViewControllerA中接收数据的委托方法
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?) {
print("Value from ViewControllerB's Delegate", item!)
}
以下是完整的代码：
视图控制器A
import UIKit
class ViewControllerA: UIViewController, ViewControllerBDelegate {
override func viewDidLoad() {
super.viewDidLoad()
}
// Delegate method
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?) {
print("Value from ViewControllerB's Delegate", item!)
}
@IBAction func goToViewControllerForDelegate(_ sender: Any) {
if let viewControllerB = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerB") as? ViewControllerB {
viewControllerB.delegate = self
if let navigator = navigationController {
navigator.pushViewController(viewControllerB, animated: true)
}
}
}
}
视图控制器B
import UIKit
//Protocol decleare
protocol ViewControllerBDelegate: NSObjectProtocol {
// Classes that adopt this protocol MUST define
// this method -- and hopefully do something in
// that definition.
func addItemViewController(_ controller: ViewControllerB?, didFinishEnteringItem item: String?)
}
class ViewControllerB: UIViewController {
var delegate: ViewControllerBDelegate?
override func viewDidLoad() {
super.viewDidLoad()
// MARK: - - - - Set Data for Passing Data through Delegate - - - - - -
delegate?.addItemViewController(self, didFinishEnteringItem: "Data for ViewControllerA")
}
}
通过通知查看器传递数据：从ViewControllerB到ViewControllerA
步骤1。在ViewControllerB中的通知查看器中设置和发布数据
let objToBeSent = "Test Message from Notification"
NotificationCenter.default.post(name: Notification.Name("NotificationIdentifier"), object: objToBeSent)
步骤2。在ViewControllerA中添加通知查看器
NotificationCenter.default.addObserver(self, selector: #selector(self.methodOfReceivedNotification(notification:)), name: Notification.Name("NotificationIdentifier"), object: nil)
步骤3。在ViewControllerA中接收通知数据值
@objc func methodOfReceivedNotification(notification: Notification) {
print("Value of notification: ", notification.object ?? "")
}
以下是完整的代码：
视图控制器A
import UIKit
class ViewControllerA: UIViewController{
override func viewDidLoad() {
super.viewDidLoad()
// Add observer in controller(s) where you want to receive data
NotificationCenter.default.addObserver(self, selector: #selector(self.methodOfReceivedNotification(notification:)), name: Notification.Name("NotificationIdentifier"), object: nil)
}
// MARK: Method for receiving Data through Post Notification
@objc func methodOfReceivedNotification(notification: Notification) {
print("Value of notification: ", notification.object ?? "")
}
}
视图控制器B
import UIKit
class ViewControllerB: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// MARK:Set data for Passing Data through Post Notification
let objToBeSent = "Test Message from Notification"
NotificationCenter.default.post(name: Notification.Name("NotificationIdentifier"), object: objToBeSent)
}
}
通过块传递数据：从ViewControllerB到ViewControllerA
步骤1。在ViewControllerB中声明块
var authorizationCompletionBlock:((Bool)->())? = {_ in}
步骤2。在ViewControllerB中设置块中的数据
if authorizationCompletionBlock != nil
{
authorizationCompletionBlock!(true)
}
步骤3。在ViewControllerA中接收块数据
// Receiver Block
controller!.authorizationCompletionBlock = { isGranted in
print("Data received from Block is: ", isGranted)
}
以下是完整的代码：
视图控制器A
import UIKit
class ViewControllerA: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
// MARK:Method for receiving Data through Block
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "showDetailSegue") {
let controller = segue.destination as? ViewControllerB
controller?.isSomethingEnabled = true
// Receiver Block
controller!.authorizationCompletionBlock = { isGranted in
print("Data received from Block is: ", isGranted)
}
}
}
}
视图控制器B
import UIKit
class ViewControllerB: UIViewController {
// MARK: Variable for Passing Data through Block
var authorizationCompletionBlock:((Bool)->())? = {_ in}
override func viewDidLoad() {
super.viewDidLoad()
// MARK: Set data for Passing Data through Block
if authorizationCompletionBlock != nil
{
authorizationCompletionBlock!(true)
}
}
}
你可以在我的GitHub上找到完整的示例应用程序。如果你对此有任何疑问，请告诉我。
OP没有提到视图控制器，但有很多答案都提到了，所以我想补充一下LLVM的一些新功能，以便在希望将数据从一个视图控制器传递到另一个视图，然后获取一些结果时更容易。
故事板片段、ARC和LLVM块使我比以往任何时候都容易。上面提到的一些答案已经提到了故事板和片段，但仍然依赖于授权。定义委托当然有效，但有些人可能会发现传递指针或代码块更容易。
使用UINavigator和segue，可以轻松地将信息传递给从属控制器并获取信息。ARC使传递从NSObjects派生的对象的指针变得简单，因此如果您希望从属控制器为您添加/更改/修改某些数据，请将指针传递给可变实例。块使传递动作变得容易，因此如果您希望从属控制器调用更高级别控制器上的动作，请传递一个块。您可以定义块以接受任何数量的对您有意义的参数。如果更适合的话，您还可以设计API以使用多个块。
下面是segue胶水的两个小例子。第一个简单明了地显示了传递给输入的一个参数，第二个用于输出。
// Prepare the destination view controller by passing it the input we want it to work on
// and the results we will look at when the user has navigated back to this controller's view.
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
[[segue destinationViewController]
// This parameter gives the next controller the data it works on.
segueHandoffWithInput:self.dataForNextController
// This parameter allows the next controller to pass back results
// by virtue of both controllers having a pointer to the same object.
andResults:self.resultsFromNextController];
}
第二个示例显示为第二个参数传递回调块。我喜欢使用块，因为它将相关细节紧密地保存在源代码中——更高级别的源代码中。
// Prepare the destination view controller by passing it the input we want it to work on
// and the callback when it has done its work.
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
[[segue destinationViewController]
// This parameter gives the next controller the data it works on.
segueHandoffWithInput:self.dataForNextController
// This parameter allows the next controller to pass back results.
resultsBlock:^(id results) {
// This callback could be as involved as you like.
// It can use Grand Central Dispatch to have work done on another thread for example.
[self setResultsFromNextController:results];
}];
}
您可以创建一个从源视图控制器到目标视图控制器的推送段，并提供如下标识符名称。
您必须像这样执行didselectRowAt的segue。
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
performSegue(withIdentifier: "segue", sender: self)
}
您可以从下面的函数传递选定项的数组。
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let index = CategorytableView.indexPathForSelectedRow
let indexNumber = index?.row
print(indexNumber!)
let VC = segue.destination as! AddTransactionVC
VC.val = CategoryData[indexNumber!] . // Here you can pass the entire array instead of an array element.
}
您必须检查目标viewcontroller的viewdidload中的值，然后将其存储到数据库中。
override func viewDidLoad{
if val != ""{
btnSelectCategory.setTitle(val, for: .normal)
}
}
我目前正在通过一个名为MCViewFactory的项目为这个问题的开源解决方案做出贡献，这个项目可以在这里找到：
Manticore iOS视图工厂
其想法是模仿Android的意图范式，使用全局工厂来管理您正在查看的视图，并使用“意图”在视图之间切换和传递数据。所有文档都在GitHub页面上，但这里有一些亮点：
初始化工厂时，在.XIB文件中设置所有视图并在应用程序委托中注册它们。
// Register activities
MCViewFactory *factory = [MCViewFactory sharedFactory];
// The following two lines are optional.
[factory registerView:@"YourSectionViewController"];
现在，在视图控制器（VC）中，只要您想移动到新的VC并传递数据，就可以创建一个新的意图并将数据添加到其字典（savedInstanceState）中。然后，只需设置工厂的当前意图：
MCIntent* intent = [MCIntent intentWithSectionName:@"YourSectionViewController"];
[intent setAnimationStyle:UIViewAnimationOptionTransitionFlipFromLeft];
[[intent savedInstanceState] setObject:@"someValue" forKey:@"yourKey"];
[[intent savedInstanceState] setObject:@"anotherValue" forKey:@"anotherKey"];
// ...
[[MCViewModel sharedModel] setCurrentSection:intent];
所有符合此要求的视图都需要是MCViewController的子类，它允许您重写新的onResume:方法，允许您访问传入的数据。
-(void)onResume:(MCIntent *)intent {
NSObject* someValue = [intent.savedInstanceState objectForKey:@"yourKey"];
NSObject* anotherValue = [intent.savedInstanceState objectForKey:@"anotherKey"];
// ...
// Ensure the following line is called, especially for MCSectionViewController
[super onResume:intent];
}
