从详细视图控制器 ios 发送回信息

Question

我对 IOS 编程非常陌生，我从一个列表应用程序开始。我在 Xcode 中使用了默认的 Master Detail View 模板，我正在尝试编辑它来做一个待办事项列表或购物清单。

这个想法是能够点击 MasterViewController 上的 + 按钮，然后进入 Add 屏幕，在此处输入信息，点击 Save 按钮，然后返回 MasterViewController 并在添加屏幕中输入信息MasterViewController 中的表。然后，如果您点击已添加的表格单元格，它将连续到 detailViewController 并仅显示信息。

我花了很多时间搜索和阅读，但我不知道该做什么。我认为这将是一个简单的应用程序，但我被打败了！任何提示或帮助将不胜感激！

我有三个视图控制器和一个项目类：

作为我的项目表的主控制器；

只显示表格行细节的细节视图控制器；

还有一个添加视图控制器，我试图将所有信息放入其中以保存到我的主控制器表中。

转到我的 Add 视图控制器的序列称为 add

转到我的详细视图控制器的序列称为 showDetail

然后我有 MasterViewController.h ：

#import <UIKit/UIKit.h>
#import "Items.h"
#import "AddViewController.h"
@interface MasterViewController : UITableViewController
@property NSMutableArray *items;
@end

MasterViewController.m

#import "MasterViewController.h"
#import "DetailViewController.h"
#import "Items.h"
@interface MasterViewController ()
@property NSMutableArray *itemsarray;
//@property NSMutableArray *stores;
//@property NSMutableArray *prices;
@end

@implementation MasterViewController
- (void)awakeFromNib {
    [super awakeFromNib];
}
- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    self.navigationItem.leftBarButtonItem = self.editButtonItem;//this is the edit button on the             master controller, top left
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
#pragma mark - Segues
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    if ([[segue identifier] isEqualToString:@"add"]) {

    }
    if ([segue.identifier isEqualToString:@"showDetail"]) {
        NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
        DetailViewController *destViewController = segue.destinationViewController;
        destViewController.item = [_itemsarray objectAtIndex:indexPath.row];
        destViewController.quantity = [_itemsarray objectAtIndex:indexPath.row];
        destViewController.store = [_itemsarray objectAtIndex:indexPath.row];
    }
}
#pragma mark - Table View
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return self.itemsarray.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
   UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"         forIndexPath:indexPath];
    Items  *toDo = _itemsarray[indexPath.row];
    cell.textLabel.text = toDo.name;
    return cell;
}
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
    // Return NO if you do not want the specified item to be editable.
    return YES;
}
- (void)tableView:(UITableView *)tableView commitEditingStyle:    (UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        [self.itemsarray removeObjectAtIndex:indexPath.row];
        [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
    } else if (editingStyle == UITableViewCellEditingStyleInsert) {
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view.
    }
}
@end

DetailViewController.h

#import <UIKit/UIKit.h>
#include "Items.h"
@interface DetailViewController : UIViewController
@property (strong, nonatomic) id detailItem;
@property (weak, nonatomic) IBOutlet UILabel *item;
@property (weak, nonatomic) IBOutlet UILabel *quantity;
@property (weak, nonatomic) IBOutlet UILabel *store;
@end

DetailViewController.h

#import "DetailViewController.h"
#import "Items.h"
@interface DetailViewController ()
@end
@implementation DetailViewController
#pragma mark - Managing the detail item
- (void)setDetailItem:(id)newDetailItem {
    if (_detailItem != newDetailItem) {
        _detailItem = newDetailItem;
        [self configureView];
    }
}
- (void)configureView {
    // Update the user interface for the detail item.
    if (self.detailItem) {
        //this is what the text box for name of item will show. it updates
        self.item.text= [self.detailItem name] ;
        //self.quantity.text= [self.detailItem quantity] ;
       //self.store.text= [self.detailItem store] ;
    }
}
- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    [self configureView];
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
@end

AddViewController.h

#import <UIKit/UIKit.h>
#include "Items.h"
#import "MasterViewController.h"
@interface AddViewController : UIViewController
@property (strong, nonatomic) id detailItem;
@property (weak, nonatomic) IBOutlet UITextField *item_text_box;
@property (weak, nonatomic) IBOutlet UITextField *quantity_text_box;
@property (weak, nonatomic) IBOutlet UITextField *store_text_box;
@end

AddViewController.m - 这是我不知道该怎么做的地方。我正在使用保存按钮调用 insertNewObject 函数，这是我不知道如何将此信息发送回 MasterView 控制器的地方（至少这是我认为我有问题的地方，我很新，所以不确定)

#import "AddViewController.h"
#import "MasterViewController.h"
@interface AddViewController ()
@end
@implementation AddViewController
- (void)viewDidLoad {
    UIBarButtonItem *saveButton = [[UIBarButtonItem alloc]     initWithBarButtonSystemItem:UIBarButtonSystemItemSave target:self action:@selector(insertNewObject:)];
    //this is the add button at the top right of master controller
    self.navigationItem.rightBarButtonItem = saveButton;   
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
- (void)insertNewObject:(id)sender {
    //this is what happens when we press our save button
    //this is what happens when the add button is pushed
    if (!self.itemsarray) {        
        self.itemsarray = [[NSMutableArray alloc] init];
    }
    [self.itemsarray insertObject:[NSDate date] atIndex:0];
    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
    [self.tableView insertRowsAtIndexPaths:@[indexPath]     withRowAnimation:UITableViewRowAnimationAutomatic];
}
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
@end

Items.h

#import <Foundation/Foundation.h>
@interface Items : NSObject
@property NSString *name;
@property NSString *store;
@property NSString *section;
@property float price;
+ (Items *)createItemWithName:(NSString *)name andPrice:(float)price andStore: (NSString *)store     andSection: (NSString*)section;
@end

Items.m

#import "Items.h"
@implementation Items
@synthesize name = _name;
@synthesize store = _store;
@synthesize price = _price;
@synthesize section = _section;
+ (Items *)createItemWithName:(NSString *)name andPrice:(float)price andStore:(NSString *)store     andSection:(NSString*)section{
    // Initialize Item
    Items *item = [[Items alloc] init];
    // Configure Item
    [item setName:name];
    [item setPrice:price];
    [item setStore:store];
    [item setStore:section];
    return item;
}
@end

这不是家庭作业，我有一个应用创意并想了解一些基础知识 - 这个应用将类似于我想做的事情的一部分。谢谢！

Answer 1

我建议创建一个类来充当您的数据模型，而不是在控制器属性中处理数据。一种方法是创建一个单例对象，并让控制器在他们想要添加或检索项目时与其交谈。

使用此策略，showDetail segue 只需要告诉数据模型选择了哪个项目编号，详细信息控制器将调用selectedItem（或某个名称）方法来检索它。

同样，添加控制器只会更新数据模型，而主控制器会通过在其表委托/数据源方法中引用模型来获取新信息。

有很多方法可以通过使用委托或通知来完成您想要做的事情，但我认为当应用变得更复杂时，拥有一个负责应用数据的类/对象更容易理解和使用.

Answer 2

您可以使用以下任何一种方法

1. 代表团

2. 方块

3. 通知

   由于您是 iOS 新手，我建议您使用委派。这很容易和简单

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请点击以下链接
Using Delegation to Communicate With Other View Controllers
Simple Stackoverflow answer