iOS sandbox mechanism---access to basic data types and basic operation of files

Sandbox fast storage and reading

Storage: [[nsuserdefaults Standarduserdefaults] setobject:@ "abc" forkey:@ "1"];

[[Nsuserdefaults standarduserdefaults] synchronize];

READ: NSString *str = [[Nsuserdefaults standarduserdefaults] objectforkey:@ "1"];

Get the location of some directories

1. Get document

NSString *document = Nssearchpathfordirectoriesindomains (NSDocumentDirectory, Nsuserdomainmask, YES). LastObject;

NSLog (@ "%@", document);

2. Get the cache

NSString *cache = Nssearchpathfordirectoriesindomains (Nscachesdirectory, Nsuserdomainmask, YES). LastObject;

NSLog (@ "%@", cache);

3. Get preference

NSString *preference = Nssearchpathfordirectoriesindomains (Nspreferencepanesdirectory, NSUserDomainMask, YES). Lastobject;

NSLog (@ "%@", preference);

4. Get TMP

NSString *tmp = Nstemporarydirectory ();

NSLog (@ "%@", TMP);

5. Get the path to the bundle

NSString *bundle = [NSBundle mainbundle].bundlepath;

NSLog (@ "%@", bundle);

Write the file into the sandbox

1. String Write

1.1 Stitching a good path

NSString *stringfilepath = [Document stringbyappendingpathcomponent:@ "String.text"];

NSLog (@ "%@", Stringfilepath);

1.2 Preparing the text to be written

NSString *str = @ "I am the text to be written";

1.3 Writing text to the text price

[STR writetofile:stringfilepath//write to file location

Atomically:yes//Safety

Encoding:nsutf8stringencoding//encoding

Error:nil]; Error

1.4 Reading the contents of a file

NSString *newstr = [NSString stringwithcontentsoffile:stringfilepath encoding:nsutf8stringencoding Error:nil];

NSLog (@ "%@", newstr);

2. Arrays

NSString *arrayfilepath = [Cache stringbyappendingpathcomponent:@ "Array.text"];

Nsarray *arr = @[@ "Gou onr", @ "blot", @ "Dhfjsk"];

[arr Writetofile:arrayfilepath Atomically:yes];

Nsarray *newaarry = [Nsarray Arraywithcontentsoffile:arrayfilepath];

NSLog (@ "%@", Newaarry);

3. Dictionary

NSString *dictfilepath = [Cache stringbyappendingpathcomponent:@ "Dict.text"];

Nsdictionary *dict = @{

@ "name": @ "Gold one",

@ "Age": @ "18",

@ "Gender": @ "female"

};

[Dict Writetofile:dictfilepath Atomically:yes];

Nsdictionary *newdict = [Nsdictionary Dictionarywithcontentsoffile:dictfilepath];

NSLog (@ "%@", newdict);

4. Picture

1. Stitching Address

NSString *imagefilepath = [Document stringbyappendingpathcomponent:@ "Guoguo.png"];

2. Get Data

UIImage *image = [UIImage imagenamed:@ "Guoguo"];

3. Write

3.1 First convert image to NSData data type

NSData *imagedata = uiimagepngrepresentation (image); Convert picture to Data

3.2 Writing to data

[ImageData Writetofile:imagefilepath Atomically:yes];

4. Read

UIImage *newimage = [UIImage Imagewithcontentsoffile:imagefilepath];

NSLog (@ "%@", newimage);

Nsfilemanager

Singleton design Pattern: The object created by the Singleton class will have only one, no matter how many times it is created, it is the same object

Nsfilemanager *filemanager = [Nsfilemanager Defaultmanager];

1. Create a folder and stitch the path to the new folder

NSString *filepath = [tmp stringbyappendingstring:@ "Test2/test3/test4"];

2. Create

[FileManager Createdirectoryatpath:filepath//

Withintermediatedirectories:yes//Decide whether you can create a folder that contains relationships

Attributes:nil//

Error:nil]; //

NSLog (@ "%@", FilePath);

3. Delete (this will only delete one of the innermost folders)

[FileManager Removeitematpath:filepath Error:nil];

4. Determine if the file exists

if ([FileManager Fileexistsatpath:stringfilepath]) {

NSLog (@ "file exists");

} else {

NSLog (@ "no");

}

5. Delete all Files

NSString *filepath2 = [tmp stringbyappendingstring:@ "test2"];

[FileManager removeitematpath:filepath2 Error:nil];

6: Get all the files under a folder

Nsarray *filearray = [FileManager contentsofdirectoryatpath:document error:nil];

NSLog (@ "Filearray =%@", Filearray);

iOS sandbox mechanism---access to basic data types and basic operation of files