删除保存在设备上的 plist 中的第一项

Question

抱歉，这有点长，但我已经为此苦苦挣扎了一个星期...我通过修改此 code 创建了一个位置跟踪 iOS 应用程序。 LocationManager 文件将新位置添加到我的 "LocationArray.plist"，该位置保存在可以通过文件共享访问的设备上。

plist 如下所示：LocationArray.plist

我创建了一个使用网络请求的方法，如果 requestReply returns "OK"，我想删除 LocationArray 中 plist 上的第一项（第 0 项）。因为它是一个已保存的配置文件，所以如果我调用 [self.myLocationArrayInPList removeObjectAtIndex:0]，它会注册它已被删除，但实际上并没有从 LocationArray.plist 中的 savedProfile 中删除。

- (void)removeLocationFromPList {
     NSString *plistName = [NSString stringWithFormat:@"LocationArray.plist"];
     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
     NSString *docDir = [paths objectAtIndex:0];
     NSString *fullPath = [NSString stringWithFormat:@"%@/%@", docDir, plistName];

     NSMutableDictionary *savedProfile = [[NSMutableDictionary alloc] initWithContentsOfFile:fullPath];
     for (NSDictionary *frame in _myLocationArrayInPlist) {
         NSString *uniqueIdentifier = [[[UIDevice currentDevice] identifierForVendor] UUIDString];
         NSNumber *two = [frame objectForKey:@"Latitude"];
         NSNumber *three = [frame objectForKey:@"Longitude"];
         NSDate *four = [frame objectForKey:@"Time"];
         NSArray *keys = [_myLocationDictInPlist allKeys];
         NSString *latitude = [two stringValue];
         NSString *longitude = [three stringValue];
         NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
         [dateFormatter setDateFormat:@"yyyy-MM-dd hh:mm:ss"];
         NSString *time = [dateFormatter stringFromDate:four];

         NSURLComponents *components = [NSURLComponents componentsWithString:@"http://api.earlyconnect.com/Product/GPSLog.ashx"];
         NSURLQueryItem *identifier = [NSURLQueryItem queryItemWithName:@"id" value:uniqueIdentifier];
         NSURLQueryItem *lat = [NSURLQueryItem queryItemWithName:@"lat" value:latitude];
         NSURLQueryItem *lng = [NSURLQueryItem queryItemWithName:@"lng" value:longitude];
         NSURLQueryItem *tim = [NSURLQueryItem queryItemWithName:@"t" value:time];
         components.queryItems = @[ identifier, lat, lng, tim ];
         NSURL *url = components.URL; // URL with parameters filled in
         NSString *urlString = [url absoluteString];

         NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:urlString]];

         NSURLSession *session = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
         [[session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
             NSString *requestReply = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
             NSData * responseData = [requestReply dataUsingEncoding:NSUTF8StringEncoding];
             NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
             if([requestReply isEqual:@"OK"])
             {
                // ERASE FIRST ITEM IN PLIST HERE
             }
         }] resume];
     }
 }

据我了解，我必须同时删除 savedProfile 中的 myLocationArrayInPlist 和 myLocatiionDictInPlist...但我不确定。请帮忙！

Answer 1

当您从字典中删除第一项时，您只是从文件的内存副本中删除，实际上并没有更改文件本身。

一旦你删除了你想删除的所有内容，你需要将字典保存回磁盘。

您可以使用：

[self.myLocationArrayInPList removeObjectAtIndex:0]
[self.myLocationArrayInPList writeToURL:URLtoFile error:&error]

在此处查看文档：https://developer.apple.com/documentation/foundation/nsdictionary/2879139-writetourl?language=objc

Answer 2

我加了

            self.myLocationArrayInPlist = [savedProfile objectForKey:@"LocationArray"];
            [self->_myLocationArrayInPlist removeObject:frame];
            [savedProfile writeToFile:fullPath atomically:YES];

这也很管用！

删除保存在设备上的 plist 中的第一项

Deleting the first item in plist saved on device

ios

objective-c

nsarray

plist

nsmutabledictionary