iphone - Reading and Writing to an NSDictionary? -

-

in app have table view user presses "add" button in nav bar , new cell added table view. data table loaded nsarray , each index in array storing nsmutabledictionary 4 key-value pairs. array saved .plist every time cell added. when user selects row in table detail view gets loaded. detail view loads data saved .plist depending on row selected.

in detail view want allow user edit data in dictionary specific row. i've been trying different things , can read data dictionary , load view when try , save data dictionary app keeps terminating.

can explain me proper way reading , writing data nsmutabledictionary?

this how i'm writing data .plist:

nsmutablearray *array = [[nsmutablearray alloc] initwithcontentsoffile:filepath];  nsmutabledictionary *dict = [[nsmutabledictionary alloc] init]; dict = [array objectatindex:selectedrow];  nsstring *tempa = [[nsstring alloc] initwithformat:@"%d pts", ivar_a]; nsstring *tempb = [[nsstring alloc] initwithformat:@"%d pts", ivar_b]; nsstring *tempc = [[nsstring alloc] initwithformat:@"%d pts", ivar_c];  [dict setvalue:tempa forkey:@"keya"]; [dict setvalue:tempb forkey:@"keyb"]; [dict setvalue:tempc forkey:@"keyc"];  [tempa release]; [tempb release]; [tempc release];  [array insertobject:dict atindex:selectedrow];  //save modified array plist [array writetofile:[self datafilepath] atomically:yes];  [dict release];  [array release];

if use [[nsmutabledictionary alloc] dictionaryfromcontentsoffile:@"pathtofile.plist], contents of dictionary still immutable, if top level container mutable. stated in apple's reference.

nsdictionary reference

the dictionary representation in file identified path must contain property list objects (nsstring, nsdata, nsdate, nsnumber, nsarray, or nsdictionary objects). more details, see property list programming guide. objects contained dictionary immutable, if dictionary mutable.

if need make data structure writable again, need make copy of loaded data structure using mutable types, like

[nsmutabledictionary dictionarywithdictionary:oorig]

etc.


Comments

Post a Comment

Popular posts from this blog

Javascript line number mapping -

-
magically formatted comments change reported line number of javascript errors in browsers; this: //@line n "f" n line number , f file name. unfortunately, //@line appears ungoogleable. know there documentation on feature, , browsers support it? (i found references here , here .) from can find available in mozilla based browsers. it using js_setoptions command can turn these options on or off depending on values passed. https://developer.mozilla.org/en/js_setoptions
Read more

c# - Is it possible to remove an existing registration from Autofac container builder? -

-
something along lines: builder.registertype<mytype>().as<itype>(); builder.registertype<mytype2>().as<itype>(); builder.deregistertype<mytype>().as<itype>() var container = builder.build(); var types = container.resolve<ienumerable<itype>>(); assert.istrue(types.count == 1); assert.istrue(types[0].gettype == typeof(mytype2)); scenario: go through bunch of assemblies , go register types want make sure have 1 implementation of given type. need before create container. track on own nice if autofac me bit. this cannot done directly using containerbuilder , unless start on new one. mind you, having first built container should able construct new container filtering away unwanted types , reusing registrations first container. this: ... var container = builder.build(); builder = new containerbuilder(); var components = container.componentregistry.registrations .where(cr => cr.activator.limittype != typ...
Read more

php - Mysql PK and FK char(36) vs int(10) -

-
i have read mysql can handle indexes , searches better if tables keys integers rather char(36) uuid's. is worth converting int(10)? note: use 1 server , have have plans use multiple databases concurrently therefore removing 1 of big reasons using uuid. our tables innodb if makes difference. thanks in advance. usually rdbms can handle integer keys pk more efficient, other datatypes. reason how build index column, yes: long dont require string (or other typed) keys, should use integers. however: char(36) , int(10) far away being equal, because int(10) much smaller, char(36). dont know, if require many different keys, should keep in mind. update, complete last paragraph: int(10) 32-bit, char(36) 36 - ^byte^ (= 288-bit). not mean, int consumes less space, means, char(36) has 4 times more different keys.
Read more