objective-c - 加载和保存 NSMutableArray 将不起作用

Question

首先，我有一个管理 NSMutableArray 的类。当类被实例化时，它应该查看是否已经有一个保存的数组并加载它，或者创建一个新的数组。

每次添加项目时都应保存。但是:没有任何反应。

#import "NEList.h"

@interface NEList()



@end

@implementation NEList
@synthesize theInternArray;



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

    if(self != nil) {
             NSLog(@"build");

        theInternArray = [[NSMutableArray alloc] initWithCapacity:20];

        return self;
    }
    return nil;
}

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

    if(self != nil) {
        NSLog(@"load");

        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"theFiles"];

        theInternArray = [NSMutableArray arrayWithContentsOfFile:filePath];

        if(theInternArray == nil) {
            theInternArray = [[NSMutableArray alloc] initWithCapacity:200];
        }
               NSLog(@"second %@", theInternArray);
        return self;
    }
    return nil;
}

-(BOOL) save {

   NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  NSString *documentsDirectory = [paths objectAtIndex:0];
   NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"theFiles"];


    return [self.theInternArray writeToFile:filePath atomically:NO];
}

-(BOOL) addObject:(NEListItem *)theItem {

    [theInternArray addObject:theItem];    [self save];





    UILocalNotification *localNotif = [[UILocalNotification alloc] init];

    localNotif.fireDate = theItem.theBestBeforeDate;
    localNotif.timeZone = [NSTimeZone defaultTimeZone];

    localNotif.alertBody = [theItem.theName stringByAppendingString:@" expires!"];
    localNotif.alertAction = NSLocalizedString(@"View Details", nil);

    localNotif.soundName = UILocalNotificationDefaultSoundName;
    localNotif.applicationIconBadgeNumber = 1;



    [[UIApplication sharedApplication] scheduleLocalNotification:localNotif];


    return true;
}


-(NEListItem *) getElementAtIndex:(NSUInteger)theIndex {
    return [theInternArray objectAtIndex:theIndex];
}

-(BOOL)removeObjectByName:(NSString *)theName {

    for (NEListItem *tempItem in theInternArray) {

        if([tempItem.theName isEqualToString:theName]) {
            [theInternArray removeObject:tempItem];
            break;
            return true;
            }
    }

            NSLog(@"Nicht gefunden");
            return false;
        }






@end

保存方法在另一个拥有 NEList 实例的类中调用

Answer 1

好的，我只更改了“initWithContent”方法和保存方法。我已经注释掉了您的代码并在其下进行了更改以使用 NSUserDefaults。 NSUserDefaults 应该保存您的数组的二进制文件，稍后将其取回并将其转换回 NSArray。如果这不起作用，请告诉我您遇到了什么错误。

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

    if(self != nil) {
        NSLog(@"load");
        /*
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"theFiles"];

        theInternArray = [NSMutableArray arrayWithContentsOfFile:filePath];

        if(theInternArray == nil) {
            theInternArray = [[NSMutableArray alloc] initWithCapacity:200];
        }
        NSLog(@"second %@", theInternArray);*/
        NSUserDefaults *uDefaults = [NSUserDefaults standardUserDefaults];
        theInternArray = [uDefaults objectForKey:@"internArray"];
        if (!theInternArray)
        {
            theInternArray = [[NSMutableArray alloc] initWithCapacity:200];
        }
        NSLog(@"%@", theInternArray);

        return self;
    }
    return nil;
}

-(BOOL) save {

    /*NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"theFiles"];*/

    NSUserDefaults *uDefaults = [NSUserDefaults standardUserDefaults];
    [uDefaults setObject:theInternArray forKey:@"internArray"];


    //return [self.theInternArray writeToFile:filePath atomically:NO];
    return [uDefaults objectForKey:@"internArray"];
}

哦，您的方法不起作用的原因是保存文件然后将其取回并不是那么简单。您需要将数组中的数据(如“item1、item2、item3 等”)打印到文件中，然后解析它并稍后使用该数据创建一个 NSArray。