Question

我使用此代码获取应用程序的文档目录中不存在的文件的路径

NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:@"restaurants.xml"];

获得这条道路：

/var/mobile/Containers/Data/Application/50BC3507-39BA-4F7A-86BA-254AB9DA6184/Documents/restaurants.xml

我的问题：如何让我的课程能够保存在数组中？

获取路径的功能：

- (NSString *)restaurantListPath {
    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:@"restaurants.xml"];
    return path;
}

编写数组的函数：

- (void)writeRestaurantListToFile:(NSMutableArray *)restaurantList {
    [restaurantList writeToFile:[self restaurantListPath] atomically:YES];
}

加载数组的功能：

- (NSMutableArray *)restaurantListOfFile {
    NSMutableArray *restaurantList = [NSMutableArray arrayWithContentsOfFile:[self restaurantListPath]];
    if (!restaurantList) {
        restaurantList = [NSMutableArray array];
    }
    return restaurantList;
}

我创建了一个包含1个JFRestaurant项目的数组，并使用上面的函数保存它。然后我用上面的函数加载它并且数组为空（初始化但没有内容）。

如果在写入文件或读取文件时出错，则数组将为空并非空。所以我认为数组的内容是问题所在。愿我的班级JFRestaurant无法写入档案。我查看了一个教程并看到，我需要实现NSCoding协议，以使我的类能够写入文件并执行该操作，但数组仍然是空的。我也试过NSKeyedArchiver和NSKeyedUnarchiver，但后来又出现了另一个错误

2014-08-25 16:52:23.969 Restaurants[5577:934385] -[__NSCFArray objectForKey:]: unrecognized selector sent to instance 0x170050860
2014-08-25 16:52:23.970 Restaurants[5577:934385] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFArray objectForKey:]: unrecognized selector sent to instance 0x170050860'
*** First throw call stack:
(0x185866084 0x1954180e4 0x18586d094 0x185869e48 0x18576f08c 0x185741d98 0x18670c9e0 0x18676e170 0x10007d3a0 0x100077cdc 0x189eb39ec 0x189f510b8 0x189f50b0c 0x189f5082c 0x189f507ac 0x189e997a0 0x1897f22a4 0x1897ece90 0x1897ecd34 0x1897ec534 0x1897ec2b8 0x18a125b54 0x18a126a00 0x18a124b84 0x18d96c6ac 0x18581e360 0x18581d468 0x18581b668 0x185749664 0x189f07140 0x189f02164 0x10007b518 0x195a8ea08)
libc++abi.dylib: terminating with uncaught exception of type NSException

JFRestaurant.h：

//
//  JFRestaurant.h
//  Restaurants
//
//  Created by Jonas Frey on 15.08.14.
//  Copyright (c) 2014 Jonas Frey. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "JFUtils.h"
#import "JFItem.h"

@interface JFRestaurant : NSObject <NSCoding>

@property (strong, nonatomic) NSString *name;
@property float score;

- (void)addItem:(JFItem *)item;
- (void)removeItem:(JFItem *)item;
- (void)removeItemAtIndex:(NSUInteger)index;
- (void)setItem:(JFItem *)item atIndex:(NSUInteger)index;
- (JFItem *)itemAtIndex:(NSUInteger)index;
- (NSUInteger)indexOfItem:(JFItem *)item;
- (NSInteger)itemCount;
- (NSMutableArray *)fullItemArray;

- (id)initWithName:(NSString *)name;
- (id)initWithName:(NSString *)name items:(NSMutableArray *)items;

@end

JFRestaurant.m

//
//  JFRestaurant.m
//  Restaurants
//
//  Created by Jonas Frey on 15.08.14.
//  Copyright (c) 2014 Jonas Frey. All rights reserved.
//

#import "JFRestaurant.h"

@interface JFRestaurant ()

@property (strong, nonatomic) NSMutableArray *items;

- (float)scoreOfItems;

@end

@implementation JFRestaurant

- (id)initWithCoder:(NSCoder *)aDecoder {
    NSString *name = [aDecoder decodeObjectForKey:JFKeyRestaurantCoderName];
    NSMutableArray *items = [aDecoder decodeObjectForKey:JFKeyRestaurantCoderItems];
    return [self initWithName:name items:items];
}

- (void)encodeWithCoder:(NSCoder *)aCoder {
    [aCoder encodeObject:_name forKey:JFKeyRestaurantCoderName];
    [aCoder encodeObject:_items forKey:JFKeyRestaurantCoderItems];
}

- (id)init {
    self = [super init];

    if (self) {
        self.name = @"Neues Restaurant";
        self.items = [[[JFUtils alloc] init] defaultItems];
        self.score = [self scoreOfItems];
    }

    return self;
}

- (id)initWithName:(NSString *)name {
    self = [super init];

    if (self) {
        self.name = name;
        self.items = [[[JFUtils alloc] init] defaultItems];
        self.score = [self scoreOfItems];
    }

    return self;
}

- (id)initWithName:(NSString *)name items:(NSMutableArray *)items {
    self = [super init];

    if (self) {
        self.name = name;
        self.items = items;
        self.score = [self scoreOfItems];
    }

    return self;
}

- (void)addItem:(JFItem *)item {
    [self.items addObject:item];
    self.score = [self scoreOfItems];
}

- (void)removeItem:(JFItem *)item {
    [self.items removeObject:item];
    self.score = [self scoreOfItems];
}

- (void)removeItemAtIndex:(NSUInteger)index {
    [self.items removeObjectAtIndex:index];
    self.score = [self scoreOfItems];
}

- (void)setItem:(JFItem *)item atIndex:(NSUInteger)index {
    [self.items setObject:item atIndexedSubscript:index];
    self.score = [self scoreOfItems];
}

- (JFItem *)itemAtIndex:(NSUInteger)index {
    return [self.items objectAtIndex:index];
}

- (NSUInteger)indexOfItem:(JFItem *)item {
    return [self.items indexOfObject:item];
}

- (NSInteger)itemCount {
    return self.items.count;
}

- (NSMutableArray *)fullItemArray {
    return self.items;
}

- (float)scoreOfItems {
    float value = 0.0f;
    float totalPossible = 0.0f;
    for (JFItem *item in self.items) {
        value += (4 - (float)item.segmentIndex) * 25.0f;
        totalPossible += 100.0f;
    }
    return value / totalPossible * 100.0f;
}

@end

感谢您的帮助 iComputerfreak

使自己的类能够保存在NSMutableArray中

0 个答案: