iOS learning Nskeyedarchiver, Nskeyedunarchiver archive

One of the forms of iOS save files is the Nskeyedarchiver, Nskeyedunarchiver archive:

The following is an example of a to-do lists software, Checklistitem is a project (data model) that contains a string text and a bool tag checked,items is the nsmutablearray of the View controller, Contains multiple checklistitem that are saved to the. plist file as a whole when the data is saved, and read the same.

1. First implement the Protocol <nscoding> in the. h file of the data model, for example:

@interface Checklistitem:nsobject <NSCoding>

2. Add the Encode and decode methods (called when Nscoder Archive and reconcile files)

-(void) Encodewithcoder: (Nscoder *) Acoder

{

[Acoder encodeObject:self.text forkey:@ "text"];

[Acoder encodeBool:self.checked forkey:@ "checked"];

}

-(ID) Initwithcoder: (Nscoder *) Adecoder

{

if (self = [super init])

{

Self.text = [Adecoder decodeobjectforkey:@ "text"];

self.checked = [Adecoder decodeboolforkey:@ "checked"];

}

return self;

}

3. Get the app sandbox document path and saved file names

-(NSString *) documentsdirectory

{

Nsarray *paths = Nssearchpathfordirectoriesindomains (NSDocumentDirectory, Nsuserdomainmask, YES);

NSString *documentsdirectory = [Paths firstobject];

return documentsdirectory;

}

-(NSString *) DataFilePath

{

return [[Self documentsdirectory] stringbyappendingpathcomponent:@ "checklists.plist"];

}

4. How to save and read. plist files in the view controller

-(void) Savechecklistitems

{

Nsmutabledata *data = [[Nsmutabledata alloc]init];

Nskeyedarchiver *archiver = [[Nskeyedarchiver alloc]initforwritingwithmutabledata:data];

[Archiver encodeobject:_items forkey:@ "Checklistitems"];

[Archiver finishencoding];

[Data writetofile:[self DataFilePath] atomically:yes];

}

-(void) Loadchecklistitems

{

NSString *path = [self datafilepath];

if ([[[Nsfilemanager Defaultmanager] Fileexistsatpath:path])

{

NSData *data = [[NSData alloc] initwithcontentsoffile:path];

Nskeyedunarchiver *unarchiver = [[Nskeyedunarchiver alloc] initforreadingwithdata:data];

_items = [Unarchiver decodeobjectforkey:@ "Checklistitems"];

[Unarchiver finishdecoding];

}

Else

{

_items = [[Nsmutablearray alloc]initwithcapacity:20];

}

}

5. Read the. plist file (if present) when the view is storyboard from the document.

-(ID) Initwithcoder: (Nscoder *) Adecoder

{

if (self = [super Initwithcoder:adecoder])

{

[Self loadchecklistitems];

}

return self;

}

6. Call the Save data method in the action method where you want to save the data (add, delete, modify an item)

[Self savechecklistitems];

iOS learning Nskeyedarchiver, Nskeyedunarchiver archive