如何停止覆盖数据 [英] How to stop overwriting data

问题描述

我想在我的iOS应用程式中储存一些资料。我使用下面的代码：

  NSArray * paths = NSSearchPathForDirectoriesInDomains（NSDocumentDirectory，NSUserDomainMask，YES）; 
 NSString * documentsDirectory = [paths objectAtIndex：0]; 
 NSString * path = [documentsDirectory stringByAppendingPathComponent：@yourPlist.plist]; 
 
 //插入数据
 NSMutableDictionary * dict = [[NSMutableDictionary alloc] init]; 
 [dict setValue：categoryField.text forKey：@Category]; 
 [dict setValue：nameField.text forKey：@Name]; 
 [dict setValue：eventField.text forKey：@Event]; 
 
 NSMutableArray * arr = [[NSMutableArray alloc] init]; 
 [arr addObject：dict]; 
 [arr writeToFile：path atomically：YES]; 
 
 
 //检索数据
 NSMutableArray * savedStock = [[NSMutableArray alloc] initWithContentsOfFile：path]; 
 for（NSDictionary * dict in savedStock）{
 NSLog（@my Note：％@，dict）;但是NSLog只显示最后一个数据...我想我i我会覆盖这里。我不能看到为什么，虽然！
 
 
 
我如何继续保存字典在数组没有覆盖？任何想法？
解决方案
由于你是一个模型对象，它会更好，如果你包括save，remove，findAll，findByUniqueId的逻辑。将使得与模型对象的工作非常简单。 
  @interface注意：NSObject 
 
 @property（nonatomic，copy）NSString * 
 @property（nonatomic，copy）NSString * name; 
 @property（nonatomic，copy）NSString * event; 
 
  - （id）initWithDictionary：（NSDictionary *）dictionary; 
 
 / *查找所有保存的注释* / 
 +（NSArray *）savedNotes; 
 
 / *保存当前注释* / 
  - （void）save; 
 
 / *从plist中删除注释* / 
  - （void）remove; 
  
保存便签
  Note * note = [Note new]; 
 note.category = ... 
 note.name = ... 
 note.event = ... 
 
 [note save]; 
  
从已保存的列表中删除
  //找到要删除的注释的引用
注意* note = self.savedNotes [index]; 
 [note remove]; 
  
查找所有保存的记录
  NSArray * savedNotes = [Note savedNotes]; 
  
 源代码 
 
I am trying to save in my iOS app some data. I use the following code :
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectory = [paths objectAtIndex:0]; 
NSString *path = [documentsDirectory stringByAppendingPathComponent:@"yourPlist.plist"];

//inserting data
NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
[dict setValue:categoryField.text forKey:@"Category"];
[dict setValue:nameField.text forKey:@"Name"];
[dict setValue:eventField.text forKey:@"Event"];

NSMutableArray *arr = [[NSMutableArray alloc] init];
[arr addObject:dict];
[arr writeToFile: path atomically:YES];


//retrieving data
NSMutableArray *savedStock = [[NSMutableArray alloc] initWithContentsOfFile: path];
for (NSDictionary *dict in savedStock) {
     NSLog(@"my Note : %@",dict);
}
However the NSLog shows me only the last data... I suppose that i am overwriting here..I cant see why though!

How can i continue to save dictionaries in the array without overwriting? Any ideas?
解决方案
Since you are making a model object it would be better if you include save, remove, findAll, findByUniqueId kind of logic built into it. Will make working with the model object very simple. 
@interface Note : NSObject

@property (nonatomic, copy) NSString *category;
@property (nonatomic, copy) NSString *name;
@property (nonatomic, copy) NSString *event;

- (id)initWithDictionary:(NSDictionary *)dictionary;

/*Find all saved notes*/
+ (NSArray *)savedNotes;

/*Saved current note*/
- (void)save;

/*Removes note from plist*/
- (void)remove;
Save a note 
Note *note = [Note new];
note.category = ...
note.name = ...
note.event = ...

[note save];
Delete from saved list
//Find the reference to the note you want to delete
Note *note = self.savedNotes[index];
[note remove];
Find all saved notes
NSArray *savedNotes = [Note savedNotes];
Source Code

                        
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