Android: find the id of the inflated buttons -

i have inflated buttons using following codes, , swap location of 2 buttons selected using simple translateanimation.

codes:

    (int k = 1; k <= quotient; k++)      {         linearlayout.layoutparams params3 = new linearlayout.layoutparams(button_width,row_height);         params3.setmargins(button_margin, button_margin, button_margin, button_margin);         btn_right = new button(this);         btn_right.setid(idd);         final int id_ = btn_right.getid();         btn_right.settext(""+question[idd]);          frame_row.addview(btn_right, params3);          btn_right.setonclicklistener(new view.onclicklistener()          {             public void onclick(view view)              {                                        btn_right = ((button) findviewbyid(id_));                 x1 = getrelativeleft(btn_right);                 y1 = getrelativetop(btn_right);                 int b = integer.parseint(""+btn_right.gettext().tostring());                 selection ++;                 if (selection%2 ==1)                 {                     selected_id1 = id_;                     selected_color1 = b;                                             custom_toast("x1=" +x1 + "\ny1=" + y1);                                                              }                 else                 {                     selected_id2 = id_;                     selected_color2 = b;                     x2 = getrelativeleft(btn_right);                     y2 = getrelativetop(btn_right);                      custom_toast("x2=" +x2 + "\ny2=" + y2);                      // first 1                      btn_right = ((button) findviewbyid(selected_id1));                     anim1=new translateanimation(0, (x2-x1), 0, (y2-y1));                      anim1.setfillafter(true);                     anim1.setduration(animationtime);                     anim1.setanimationlistener(game.this);                       btn_right.startanimation(anim1);                      // second 1                     btn_right = ((button) findviewbyid(selected_id2));                     anim2=new translateanimation(0, (x1-x2), 0, (y1-y2));                     anim2.setfillafter(true);                     anim2.setduration(animationtime);                     anim2.setanimationlistener(game.this);                     btn_right.startanimation(anim2);                                                 }  @override public void onanimationend(animation animation)  {      if (animation == anim1)     {                    custom_toast("1 clear");         btn_right = ((button) findviewbyid(selected_id1));         btn_right.clearanimation();     // line 426      }     if (animation == anim2)     {                    custom_toast("2 clear");         btn_right = ((button) findviewbyid(selected_id2));         btn_right.clearanimation();          } } 

logcat:

04-21 21:28:00.728: e/androidruntime(11341): java.lang.nullpointerexception 04-21 21:28:00.728: e/androidruntime(11341):    @ com.abc.abc.game.onanimationend(game.java:426) 

question:

for info, if selection%2 ==1, means user has pressed first button , not yet ready swap, , hence record id , x, y coordinates. if selection%2 ==0, means user has pressed 2 buttons , ready swap after recording 2nd's x , y.

also, (x1, y1) , (x2, y2) coordinates reporting correctly.

it runs npe @ line 426 btn_right.clearanimation(); (as specified above) . question is, since buttons inflated, , have setid inflated buttons, why still runs out npe @ line 426, or how should specify 2 buttons user has touched implement swapping animation?

thanks!!

create list of buttons, can create buttons , set id, tags , onclicklistenners , add them button list:

 buttonlist = new arraylist<button>();      (int i=0;i<2;i++){         button button = new button(getapplicationcontext());         button.setonclicklistener(customlistenner);         button.setanimation(anim);         button.setid(i);         button.settag(i);         mylayout.addview(button);         buttonlist.add(button);     } 

and when need use button again, call id or tags list. (buttonlist.get(0).getid())

if need different listenners, can control them using unique tag check in if function , declare action.

this method use when need create , use animations on dynamic views programmatically.