Question

我正在尝试向我的plist添加一个新项目。但是，每次按保存时它都会被覆盖：

-(IBAction)save:(id)sender {

 appDelegate = (JobTestAppDelegate*)[[UIApplication sharedApplication]delegate]; 

 NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
 NSString *documentsDirectory = [paths objectAtIndex:0];
 NSString *fileName = [documentsDirectory stringByAppendingPathComponent:@"Work.plist"];

 NSMutableDictionary* newNote = [[NSMutableDictionary alloc] init];  

 NSMutableDictionary *set = [NSMutableDictionary dictionaryWithObjects:[NSArray arrayWithObjects:@"", @"", nil] forKeys:[NSArray arrayWithObjects:@"Work Name", @"Work ID", nil]];

NSArray *work = [NSArray arrayWithObjects:set, nil];

int row = 0;
newNote = [appDelegate.job objectAtIndex:row];
[newNote setValue:work forKey:@"Work"];         

[appDelegate.job writeToFile:fileName atomically:TRUE];

[newNote release];  

[self dismissModalViewControllerAnimated:YES];
 }

我不知道代码的哪一部分是错的。我一直试图解决这个问题好几天。

编辑： appDelegate.job - 我的主应用委托类中的一个可变数组，用于创建plist：

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *fileName = [documentsDirectory stringByAppendingPathComponent:@"Work.plist"];

job = [[NSMutableArray alloc] initWithContentsOfFile:fileName];


[job writeToFile:fileName atomically:YES];

EDIT2：

我需要将用户输入（NSArray * work）存储到工作数组

中

Root（数组）

        Item 0 (Dict)
                      Name (String)
                      Work (Array)
                                       Item 0 (Dict)
                                                    Work Name (String)
                                                    Work ID (String)
                                       Item 1 (Dict)
                                                    Work Name (String)
                                                    Work ID (String)
        Item 1 (Dict)
                      Name (String)
                      Analysis (Array)
                                       Item 0 (Dict)
                                                    Work Name (String)
                                                    Work ID (String)
                                       Item 1 (Dict)
                                                    Work Name (String)
                                                    Work ID (String)

EDIT3： NSMutableDictionary * newNote = [[NSMutableDictionary alloc] init];

 NSMutableDictionary *set = [NSMutableDictionary dictionaryWithObjects:[NSArray arrayWithObjects:@"", @"", nil] forKeys:[NSArray arrayWithObjects:@"Work Name", @"Work ID", nil]];

NSArray *work = [NSArray arrayWithObjects:set, nil];

int row = item;
newNote = [appDelegate.job objectAtIndex:row];
[newNote setValue:work forKey:@"Work"];         

//i think this is the line which i am having problem with.
//without this line my data in the plist gets overwritten, 
//with this code it copies the who item and create a new item into my root array
[appDelegate.job addObject:newNote];

[appDelegate.job writeToFile:fileName atomically:TRUE];

[newNote release];

先谢谢，李亚男

Answer 1

您正在使用新项目覆盖作业索引为零的任何内容。你也在这里分配内存：

NSMutableDictionary* newNote = [[NSMutableDictionary alloc] init];

然后在此处为此变量重新分配其他内容：

newNote = [appDelegate.job objectAtIndex:row];

如果您尝试添加新项目，则应执行以下操作：

NSMutableDictionary* newNote = [[NSMutableDictionary alloc] init];
[newNote setValue:work forKey:@"Work"];
[appDelegate.job addObject:newNote];
[appDelegate.job writeToFile:fileName atomically:TRUE];

然后，您将新的字典添加到作业数组，并写出整个数组。

编辑：从你的评论看，newNote看起来应该是一个字典，里面有一个名字和一个数组。因此，您需要向现有数组添加新对象 - 您当前正在将单个项目数组设置为此字典的“work”键。

您需要以下内容：

NSMutableDictionary* newNote = [appDelegate.job objectAtIndex:0];
NSArray *oldWork = [newNote objectForKey:@"Work"];
NSArray *newWork = [oldWork arrayByAddingObject:set];
[newNote setObject:newWork forKey:@"Work"];

为什么plist中的项被覆盖？

1 个答案: