java - Should I use one global Retrofit instance or create one for each request in Android? -

well, lost in using retrofit now... @ first write singleton helper class hold service instance created retrofit instance. convenient service , make http request, find can't access token sharedpreferences, because helper instance static. because use authenticator interface deal authentication, not possible pass access token when making request. try extend application class , hold application instance in static field, android studio give me warning(do not place android context classes in static fields; memory leak (and breaks instant run)).

so have choice: write static helper method that, each request, accepts access token, build retrofit instance, create service instance , make request. confusing whether best practice. what's difference between reusing 1 service instance , creating service each request?

ps: word service above refers service instance created someretrofit.create(someserviceinterface.class), not android.app.service.

i suggest go ahead singleton approach only,as design prospective .

if create multiple instance of service each 1 of them have different network properties readtimeout , writetimeout , response logging property , etc or have set them 1 single property , if our working in team give alot of headache.

and usercase faced , @ later point of time backend team on additional header param each request device os version have add property retrofit client pain .

here snippet of code , how handle headers .

public static retrofit getrestadapter(final hashmap<string, string> requestheadermap) {     httplogginginterceptor interceptor = new httplogginginterceptor();     interceptor.setlevel(httplogginginterceptor.level.body);     okhttpclient client = new okhttpclient.builder()             .addinterceptor(interceptor)             .addinterceptor(rewrite_cache_control_interceptor)             .addnetworkinterceptor(new interceptor() {                 @override                 public response intercept(chain chain) throws ioexception {                     request.builder builder = chain.request().newbuilder();                     set<map.entry<string, string>> entryset = requestheadermap.entryset();                     (map.entry<string, string> entry : entryset) {                         if (entry.getvalue().isempty())                             builder.removeheader(entry.getkey());                         else                             builder.addheader(entry.getkey(), entry.getvalue());                     }                      request request = builder.build();                     return chain.proceed(request);                 }               }).build();      return new retrofit.builder()             .baseurl(constants.base_url)             .client(client)             .addconverterfactory(gsonconverterfactory.create())             .build(); } 

and instance of requestheadermap global instance , data being pushed using observable pattern .

i hope take decision .