android - adding back button support in a activity while using variables of a fragment -

public class mainactivity extends activity {  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);      fragment_view frag=new fragment_view();     fragmentmanager manager=getfragmentmanager();     fragmenttransaction transaction=manager.begintransaction();     transaction.add(r.id.fragment,frag,"hey");     transaction.commit(); } @override  public boolean onkeydown(int keycode, keyevent event) {  if (keycode == keyevent.keycode_back) {   if (incustomview()) {  hidecustomview();  return true;  }  if ((mcustomview == null) && webview.cangoback()) {  webview.goback();  return true;  }  }  return super.onkeydown(keycode, event);  } 

now here variables incustomview , hidecustomview defined in fragment. how add button support on activity while using variables fragment. want implement button support in android activity while using defined variables fragment.

public class fragment_view extends fragment{  private webview webview; private framelayout customviewcontainer; private webchromeclient.customviewcallback customviewcallback; private view mcustomview; private mywebchromeclient mwebchromeclient; private mywebviewclient mwebviewclient;  @override public view oncreateview(layoutinflater inflater, viewgroup container,         bundle savedinstancestate) {     // todo auto-generated method stub     view view= inflater.inflate(r.layout.fragment_view, container,false);     customviewcontainer = (framelayout)view.findviewbyid(r.id.customviewcontainer);         webview = (webview)view. findviewbyid(r.id.webview);          mwebviewclient = new mywebviewclient();         webview.setwebviewclient(mwebviewclient);          mwebchromeclient = new mywebchromeclient();         webview.setwebchromeclient(mwebchromeclient);         webview.getsettings().setjavascriptenabled(true);         webview.getsettings().setappcacheenabled(true);         webview.getsettings().setbuiltinzoomcontrols(true);         webview.getsettings().setsaveformdata(true);         string htmlfile = "file:///" + environment.getexternalstoragedirectory()                 .getpath()                 + "/video_nsta/index.html";         webview.loadurl(htmlfile);      return view; }   public boolean incustomview() {     return (mcustomview != null); }  public void hidecustomview() {     mwebchromeclient.onhidecustomview(); }   @override public void onpause() {     super.onpause();         webview.onpause(); }  @override public void onresume() {     super.onresume();         webview.onresume(); }  @override public void onstop() {     super.onstop();         if (incustomview()) {         hidecustomview();     } }      class mywebchromeclient extends webchromeclient {      @override     public void onshowcustomview(view view, int requestedorientation, customviewcallback callback) {          onshowcustomview(view, callback);         }      @override     public void onshowcustomview(view view,customviewcallback callback) {           if (mcustomview != null) {             callback.oncustomviewhidden();             return;         }         mcustomview = view;         webview.setvisibility(view.gone);         customviewcontainer.setvisibility(view.visible);                  customviewcontainer.addview(view);         customviewcallback = callback;      }        @override     public void onhidecustomview() {         super.onhidecustomview();              if (mcustomview == null)             return;         webview.setvisibility(view.visible);        customviewcontainer.setvisibility(view.gone);         mcustomview.setvisibility(view.gone);         customviewcontainer.removeview(mcustomview);         customviewcallback.oncustomviewhidden();          mcustomview = null;     } }  class mywebviewclient extends webviewclient {     @override     public boolean shouldoverrideurlloading(webview view, string url) {         return super.shouldoverrideurlloading(view, url);        } }  } 

it's matter of distributing button.

first create fragment can handle it:

public abstract class backbuttonfragment extends fragment{    public boolean onbackpressed(){         return false; // defaults false    } } 

then change fragments extend backbuttonfragment.

then on activity use appropriate callback backbutton (remove onkeydown activity , use instead):

@override public void onbackpressed() {      fragment f = getfragmentmanager().findfragmentbyid(r.id.fragment);     if(f instanceof backbuttonfragment){         if(((backbuttonfragment)f).onbackpressed())              return;     }      // if fragment didn't use button normal stuff     super.onbackpressed(); } 

then inside each 1 of fragments override method onbackpressed , return correct value true or false depending on needs.