android - Libgdx : Clicklistener doesnt work on resize -

my code functional if take out screen resize concern. have tried on multiple devices including tablet , resolution bad. trying keep same aspect ratio of viewport. using stage add buttons , images. clicklistener responding part in gutter , part on play button. stackoverflow not letting me post image because of new account. please me in understanding doing wrong , make sure piece of code works on phones , desktop.

private static final int virtual_width = 480; private static final int virtual_height = 800;  public void resize(int width, int height) {     // calculate new viewport      vector2 size = scaling.fit.apply(virtual_width, virtual_height, width, height);     int viewportx = (int)(width - size.x) / 2;      int viewporty = (int)(height - size.y) / 2;     int viewportwidth = (int)size.x;     int viewportheight = (int)size.y;      gdx.gl.glviewport(viewportx, viewporty, viewportwidth, viewportheight); }  @override public void show() {      batch = new spritebatch();     stage = new stage();     camera = new orthographiccamera(virtual_width, virtual_height);      camera.settoortho(true, virtual_width, virtual_height);      worldcoords  = new vector3( virtual_width, virtual_height, 0);     camera.unproject(worldcoords);     camera.update();       white = new bitmapfont(gdx.files.internal("font/white.fnt"), true);     white.setscale(1f, -1f);      skin = new skin();     atlas = new textureatlas("button.pack.pack");     skin.addregions(atlas);     buttonstyle = new textbuttonstyle();     buttonstyle.up = skin.getdrawable("button");     buttonstyle.down = skin.getdrawable("buttonpressed");     buttonstyle.font = white;     buttonstyle.fontcolor = color.black;         buttonplay =new textbutton("play", buttonstyle);     buttonplay.setwidth(virtual_width/3);     buttonplay.setheight(virtual_height/12);      buttonplay.setposition(stage.getviewport().getrightgutterwidth(), stage.getviewport().getworldheight()/2);       buttonplay.addlistener(new clicklistener(){          @override         public void clicked(inputevent event, float x, float y){              ((game) gdx.app.getapplicationlistener()).setscreen(new mainflow(g));          }     });      gdx.input.setinputprocessor(stage);       image img = new image(new texture(gdx.files.internal("optimized-bg_2.png")));     img.setfillparent(true);       stage.addactor(img);     stage.addactor(buttonplay);   }  @override public void render(float delta) {      camera.update();     batch.setprojectionmatrix(camera.combined);      gdx.gl.glclearcolor(0, 0, 0, 1);     gdx.gl.glclear(gl20.gl_color_buffer_bit);      stage.act();     stage.draw();  } 

i don't understand want, @ first try update stage, in resize method, , read libgdx docs

  stage.getviewport().update(width, height, true);