objective c - -[ViewAController doLogin:]: unrecognized selector sent to instance 0x6901bc0 -

this login.m

 #import    @interface login : uiviewcontroller {     iboutlet uitextfield *username;     iboutlet uitextfield *password;     iboutlet uiactivityindicatorview *loginactivity; } @property (nonatomic, retain) iboutlet uitextfield              *username; @property (nonatomic, retain) iboutlet uitextfield              *password; @property (nonatomic, retain) iboutlet uiactivityindicatorview  *loginactivity; - (ibaction) dologin:(id)sender;  @end 

and login.h

  #import "login.h"  @implementation login  @synthesize username,password;  - (ibaction) dologin:(id)sender {     [ password resignfirstresponder ];     [ loginactivity startanimating ];     nslog(@"%@ / %@", [ username text ], [ password text ] ); } - (void)didreceivememorywarning {     [super didreceivememorywarning]; }  - (void)viewdidunload {     [super viewdidunload];     // release retained subviews of main view.     // e.g. self.myoutlet = nil; } - (void)dealloc {     [super dealloc]; } @end 

if press login(dologin) got error -[viewacontroller dologin:]: unrecognized selector sent instance

it looks you've named class "login", have hooked button instance of "viewacontroller". viewacontroller doesn't have dologin: method?