android - my second activity is not returning result for first one -

i trying make app in mainactivity ask result main2activity code mainactivity is:

package hello.option_menu;  import android.app.activity; import android.content.intent; import android.support.v7.app.appcompatactivity; import android.os.bundle; import android.view.menu; import android.view.menuinflater; import android.view.menuitem; import android.view.view; import android.widget.button; import android.widget.edittext; import android.widget.textview;  import com.ye.collor.stackapplication.r;  public class mainactivity extends appcompatactivity {     button bt;     textview tv;     @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);         button bt=(button)findviewbyid(r.id.bt);         textview tv=(textview)findviewbyid(r.id.tv) ;         bt.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view arg0) {                 intent i=new intent(mainactivity.this,main2activity.class);                 startactivityforresult(i,1);             }         });       }      @override     protected void onactivityresult(int requestcode, int resultcode, intent data) {         super.onactivityresult(requestcode, resultcode, data);         if(requestcode==1)         {             string message=data.getstringextra("message");             tv.settext(message);         }     }      @override     public boolean oncreateoptionsmenu(menu menu) {          menuinflater inflater = getmenuinflater();         inflater.inflate(r.menu.jai, menu);          return true;     }  } 

code of main2activity is:

package hello.option_menu; import android.content.intent; import android.support.v7.app.appcompatactivity; import android.os.bundle; import android.view.menu; import android.view.menuinflater; import android.view.view; import android.widget.button; import android.widget.edittext;  import com.ye.collor.stackapplication.r;  public class main2activity extends appcompatactivity {     button bt;     edittext et;     @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main2);         bt=(button)findviewbyid(r.id.button);         et=(edittext)findviewbyid(r.id.et);         bt.setonclicklistener(new view.onclicklistener()         {             @override             public void onclick(view arg0) {                  string message=et.gettext().tostring();                 intent intent=new intent();                 intent.putextra("message",message);                 setresult(1,intent);                 finish();              }         });     }     public boolean oncreateoptionsmenu(menu menu) {          menu.add("hello");          menuinflater inflater=getmenuinflater();         inflater.inflate(r.menu.jai,menu);          return true;     }  } 

so view of app is:my mainactivity

my main2activity

so when click send button after typing text in main2activity set text written in mainactivity didn't that.it still remain "hello world",so text not change .i unable trouble shoot problem.

in mainactivity2 change

setresult(1,intent); 

to

setresult(result_ok,intent); 

what trying set hardcoded value of result_type 1 int value result_first_user whereas intended set result_ok

also value of 1 assuming requestcode in m=mainactivity2 not request_code result_code. requestcode remains in mainactivity , can used distinguish between different activities open.

also can change onactivityresult follows keep more safer

protected void onactivityresult(int requestcode, int resultcode, intent data) {     super.onactivityresult(requestcode, resultcode, data);     if(requestcode==1 && resultcode==result_ok)     {         string message=data.getstringextra("message");         tv.settext(message);     } } 

update 1 mentioned crashes after this, because textview not initialized in mainactivity.

so in mainactivity change

textview tv=(textview)findviewbyid(r.id.tv) ; 

to

tv=(textview)findviewbyid(r.id.tv) ; 

so textview declared globally assigned value when return in onactivityresult