ios - 从详细 View Controller ios 发送回信息

Question

我是 IOS 编程的新手，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，我正在尝试对其进行编辑以创建待办事项列表或购物 list 。

我们的想法是能够点击 MasterViewController 上的 + 按钮，然后进入添加屏幕，在那里输入信息，点击保存按钮，然后返回到 MasterViewController，并在添加屏幕中填充信息输入MasterViewController 中的表。然后，如果您点击已添加的表格单元格，它将继续到 detailViewController 并仅显示信息。

我花了很多时间搜索和阅读，但我只是不知道该怎么做。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 View Controller 和一个项目类:

主 Controller 是我的项目表；

只显示表行详细信息的详细 View Controller ；

和一个添加 View Controller ，我试图将所有信息放入其中以保存到我的主 Controller 表中。

进入我的添加 View Controller 的序列称为添加

转到我的详细信息 View Controller 的序列称为 showDetail

然后我有了 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 - 这是我不确定要做什么的地方。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 Controller 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

项目.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

元素.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，我有一个应用程序创意，想了解一些基础知识 - 这个应用程序将类似于我想做的事情的一部分。谢谢!

Answer 1

我建议创建一个类作为您的数据模型，而不是在您的 Controller 属性中处理数据。一种方法是创建一个单例对象，并让 Controller 在它们想要添加或检索项目时与其对话。

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 Controller 将调用 selectedItem(或某个名称)方法来检索它。

类似地，添加 Controller 将只更新数据模型，而主 Controller 将通过在其表委托(delegate)/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(delegate)或通知来完成您想要做的事情，但我认为当应用程序变得更加复杂时，拥有一个负责应用程序数据的类/对象更容易理解和使用.