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
共享数据有多种方法。
您始终可以使用NSUserDefaults共享数据。设置要与所选键共享的值，并在下一个视图控制器中从与该键关联的NSUserDefault获取值。[[NSUserDefaults standardUserDefaults]setValue:key:key的值][[NSUserDefaults standardUserDefaults]objectForKey:key]您只需在viewcontrollerA中创建一个属性。在viewcontrollerB中创建viewcontrollerA的对象，并为该属性分配所需的值。您也可以为此创建自定义代理。
在下一个视图controller.h文件中创建属性，并定义getter和setter。
在NextVC上的NextVC.h中添加此属性：
@property (strong, nonatomic) NSString *indexNumber;
Add
@综合索引编号；在NextVC.m中
最后一个
NextVC *vc = [[NextVC alloc]init];
vc.indexNumber = @"123";
[self.navigationController vc animated:YES];
这是一个非常棒的教程，适合任何想要的人。下面是示例代码：
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
if ([segue.identifier isEqualToString:@"myIdentifer]) {
NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
myViewController *destViewController = segue.destinationViewController;
destViewController.name = [object objectAtIndex:indexPath.row];
}
}
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。
嗯，我们有几种方法可以使用委派系统或使用故事板Segue：
使用setter和getter方法，如viewController.h@属性（保留，非原子）NSString*str；现在，在viewController.m中@合成str；这里我有一个PDF URL和一个segue到另一个viewController，像这样，pdfObject是我的pdfModel。它基本上是一个NSOBJECT类。str=[NSString stringWithFormat:@“%@”，pdfObject.objPath]；NSLog（@“pdfUrl:***：%@：***：”，pdfUrl）；[self-performSegueWithIdentifier:@“programPDFViewController_segue”sender:self]；#pragma标记-导航//在基于情节提要的应用程序中，您通常需要在导航之前做一些准备-（void）准备segue:（UIStoryboardSegue*）segue发件人：（id）发件人{if（[[segue identifier]isEqualToString:@“programPDFViewController_segue”]）{programPDFViewController*pdfVC=[segue destinationViewController]；[pdfVC setRecivedPdfUrl:str]；}}现在，我成功地接收了我的PDF URL字符串和其他ViewController，并在webview中使用该字符串。。。在处理这样的委托时，我有一个NSObject实用程序类，其中包含我的dateFormatter、sharedInstance、EscapeWhiteSpaceCharacters、convertImageToGrayScale等方法，以及我在整个应用程序中使用过的其他方法，现在在文件实用程序中使用。在这种情况下，您不需要在每次将数据从一个视图控制器解析到另一个视图时都创建变量。有一次，您在fileutility.h中创建了一个字符串变量。只需将其设为零并再次使用。@接口实用程序：NSObject文件实用程序.h：+（实用程序*）共享实例；@属性（非原子，保留）NSString*strUrl；现在在文件实用程序.m中：@实施实用程序+（实用程序*）共享实例{静态实用程序*sharedObj=nil；如果（sharedObj==nil）{sharedObj=[[utilities alloc]init]；}返回sharedObj；}现在完成了，请访问文件firstViewController.m并调用委托NSString*str=[NSString stringWithFormat:@“%@”，pdfObject.objPath]；[连接共享实例].strUrl=nil；[连接共享实例].strUrl=str；现在直接转到文件secondViewController.m，在不创建变量的情况下使用它我所做的一切：-（无效）视图将出现：（BOOL）动画{[超级视图将出现：是]；[self-webViewMethod:[Connection sharedInstance].strUrl]；}-（void）WebViewMethod:（NSString）Url{//使用webview。享受编码：D}
这种委托工作在内存管理方面是可靠的。
