从单例类中的 NSDictionaies 数组访问数据并在 TableView (XCode) 中显示该数据）

Question

我有一个单例类，其中包含一个 NSDictionary 数组（其中 5 个）。我需要在不同的 ViewController 中显示这些数据（我正在使用 Storyboard）。

如果我从数组中提取数据，我可以访问数据，但现在我需要从 NSDictionary 数组中提取数据。我想出了这一行：

cell.textLabel.text =  [[[[Singleton sharedInstance] movies]  objectAtIndex:indexPath.row] objectForKey:@"title"];

但这似乎不起作用。

有什么想法吗？我将把我的 Singleton 类和我的 TableView 类：

Singleton.h

#import <Foundation/Foundation.h>
#import "AppDelegate.h"

@interface Singleton : NSObject {

    NSDictionary *batman;
    NSDictionary *superman;

    NSArray *superheoes;

}

@property(nonatomic,retain) NSDictionary *batman;
@property(nonatomic,retain) NSDictionary *superman;

@property(nonatomic,retain) NSArray *superheroes;

+ (Singleton *) sharedInstance;
+ (AppDelegate *) sharedAppDelegate;

@end

Singleton.m

#import "Singleton.h"

@implementation Singleton

@synthesize batman, superman;

+ (Singleton *) sharedInstance {

    //The instance of this class is store here
    static Singleton *myInstance = nil;

    // We check to see if an instance already exists
    if (nil == myInstance) {
        myInstance = [[[self class] alloc] init];
    }

    return myInstance;

}

-(id) init {

    if (self=[super init]) {

        batman = [[NSDictionary alloc] initWithObjectsAndKeys: 
                             @"name", @"Back to the Future", 
                             @"year", @"1985", nil];

        superman = [[NSDictionary alloc]initWithObjectsAndKeys:
                    @"name", @"Superman", 
                    @"year", @"1990", nil];

        superheroes = [NSArray arrayWithObjects:batman,superman, nil]; 
    }
    return self;
}

#pragma mark access to app delegate etc.
+ (AppDelegate *) sharedAppDelegate; {
    return (AppDelegate*)[[UIApplication sharedApplication] delegate];
}



@end

SuperheroesDatabase.m

#import "SuperheroesDatabase.h"
#import "Singleton.h"

@interface SuperheroDatabase ()

@end

@implementation MovieDatabase

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    // Configure the cell...

    if(cell == nil) {

        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];

    }


    cell.textLabel.text =  [[[[Singleton sharedInstance] movies]  objectAtIndex:indexPath.row] objectForKey:@"name"];
    //cell.detailTextLabel.text =  [NSString stringWithFormat:@"row %i", indexPath.row];

    return cell;
}

Answer 1

我认为您的问题是您的数组和字典没有被正确保留。尝试在您的 init 方法中添加 retain 调用：

-(id) init {

    if (self=[super init]) {

        batman = [[[NSDictionary alloc] initWithObjectsAndKeys: 
                             @"name", @"Back to the Future", 
                             @"year", @"1985", nil] retain];

        superman = [[[NSDictionary alloc]initWithObjectsAndKeys:
                    @"name", @"Superman", 
                    @"year", @"1990", nil] retain];

        superheroes = [[NSArray arrayWithObjects:batman,superman, nil] retain]; 
    }
    return self;
}