how to programmatically show and hide action bar on one activity

Question

i got this one activity wherein i need to hide actionbar on the login interface then once login it will show the action bar.i got one activity only. if i put getActionBar on the main activity it gives me error.

heres the code:

@SuppressLint("NewApi") public class MainActivity extends Activity {   ViewPager viewPager; PagerAdapter adapter; ProgressDialog pDialog; ImageView imgLogo; Menu menu1;  ImageView header; ImageView footer;   int[] bookCover = new int[] {                       R.drawable.image1,                      R.drawable.image2,                     R.drawable.image3,                      };   @SuppressLint("NewApi") @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);     setupFacebookConnect(savedInstanceState);      imgLogo = (ImageView)findViewById(R.id.logo);     share = (ImageView) findViewById(R.id.share);      // Locate the ViewPager in viewpager_main.xml     viewPager = (ViewPager) findViewById(R.id.pager);     // Pass results to ViewPagerAdapter Class     adapter = new ViewPagerAdapter(this, bookCover);     // Binds the Adapter to the ViewPager     viewPager.setAdapter(adapter);      final OnPageChangeListener pageChangeListener = new ViewPager.SimpleOnPageChangeListener() {          @SuppressLint("NewApi")         @Override         public void onPageSelected(int position) {              final int pos = position;             share.setOnClickListener(new OnClickListener() {                  @Override                 public void onClick(View v) {                      switch(pos) {                     case 0:                          break;                     case 1:                           break;                     case 2:                          break;                                                                   case 3:                          break;                                                                    }                  }             });          // When changing pages, reset the action bar actions since they are dependent          // on which page is currently active. An alternative approach is to have each          // fragment expose actions itself (rather than the activity exposing actions),          // but for simplicity, the activity provides the actions in this sample.                    invalidateOptionsMenu();          }      };           viewPager.setOnPageChangeListener(pageChangeListener);     pageChangeListener.onPageSelected(0);       facebook_connect = (Button) findViewById(R.id.facebook_login);     facebook_connect.setOnClickListener(new OnClickListener() {          @Override         public void onClick(View arg0) {             if (isFacebookConnected()) {                 disConnectFacebook();             } else {                 connectFacebook();             }          }     });       // Shared Preferences     mSharedPreferences = getApplicationContext().getSharedPreferences("MyPref", 0);  }   @SuppressLint({ "InlinedApi", "NewApi" })     @Override     public boolean onCreateOptionsMenu(Menu menu) {          this.menu1 = menu;          super.onCreateOptionsMenu(menu);         getMenuInflater().inflate(R.menu.main, menu);          menu.findItem(R.id.action_previous).setEnabled(viewPager.getCurrentItem() > 0);          // Add either a "next" or "finish" button to the action bar, depending on which page         // is currently selected.         MenuItem item = menu.add(Menu.NONE, R.id.action_next, Menu.NONE,(viewPager.getCurrentItem() == adapter.getCount() - 1)                         ? R.string.action_finish                         : R.string.action_next);          item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM | MenuItem.SHOW_AS_ACTION_WITH_TEXT);          return true;      }      @Override     public boolean onOptionsItemSelected(MenuItem item) {          int itemId = item.getItemId();         if (itemId == R.id.action_previous) {             // Go to the previous step in the wizard. If there is no previous step,             // setCurrentItem will do nothing.             viewPager.setCurrentItem(viewPager.getCurrentItem() - 1);             return true;         } else if (itemId == R.id.action_next) {             // Advance to the next step0.0 in the wizard. If there is no next step, setCurrentItem             // will do nothing.             viewPager.setCurrentItem(viewPager.getCurrentItem() + 1);             return true;         }          return super.onOptionsItemSelected(item);     }   private Session.StatusCallback statusCallback = new FBSessionStatus();  public void setupFacebookConnect(Bundle savedInstanceState) {     Settings.addLoggingBehavior(LoggingBehavior.INCLUDE_ACCESS_TOKENS);      Session session = Session.getActiveSession();     if (session == null) {         if (savedInstanceState != null) {             session = Session.restoreSession(this, null, statusCallback,                     savedInstanceState);         }         if (session == null) {             session = new Session(this);         }         Session.setActiveSession(session);         if (session.getState().equals(SessionState.CREATED_TOKEN_LOADED)) {             session.openForRead(new Session.OpenRequest(this)                     .setCallback(statusCallback));         }     } }  public boolean isFacebookConnected() {     Session session = Session.getActiveSession();     return (session.isOpened()) ? true  : false;  }  public void connectFacebook() {     Session session = Session.getActiveSession();     if (!session.isOpened() && !session.isClosed()) {         getActionBar().show();         session.openForRead(new Session.OpenRequest(this)                 .setCallback(statusCallback));            } else {     Session.openActiveSession(this, true, statusCallback);      } }  @Override public void onStart() {     super.onStart();     Session.getActiveSession().addCallback(statusCallback); }  @Override public void onStop() {     super.onStop();     Session.getActiveSession().removeCallback(statusCallback); }  @Override protected void onSaveInstanceState(Bundle outState) {     super.onSaveInstanceState(outState);     Session session = Session.getActiveSession();     Session.saveSession(session, outState); }  @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {     super.onActivityResult(requestCode, resultCode, data);     Session.getActiveSession().onActivityResult(this, requestCode,             resultCode, data); }  public class FBSessionStatus implements Session.StatusCallback {      @Override         public void call(Session session, SessionState state, Exception exception) {             onSessionStateChange(session, state, exception);         } }  public void disConnectFacebook() {     Session session = Session.getActiveSession();     if (!session.isClosed()) {         session.closeAndClearTokenInformation();         viewPager.setVisibility(View.INVISIBLE);         MenuItem item1 = menu1.findItem(R.id.action_next);         item1.setVisible(false);         MenuItem item2 = menu1.findItem(R.id.action_previous);         item2.setVisible(false);            imgLogo.setVisibility(View.VISIBLE);         //btnLoginTwitter.setVisibility(View.VISIBLE);          share.setVisibility(View.INVISIBLE);      }  }  private void onSessionStateChange(Session session, SessionState state, Exception exception) {         // Check if the user is authenticated and         // a deep link needs to be handled.         if (state.isOpened()) {              MenuItem item1 = menu1.findItem(R.id.action_next);             item1.setVisible(true);             MenuItem item2 = menu1.findItem(R.id.action_previous);             item2.setVisible(true);             //getActionBar().show();              share.setVisibility(View.VISIBLE);              //btnLoginTwitter.setVisibility(View.INVISIBLE);             //btnShare.setVisibility(View.VISIBLE);                   viewPager.setVisibility(View.VISIBLE);              imgLogo.setVisibility(View.INVISIBLE);            }      }  public void shareImage(String name, String caption, String desc, String link, String picture ) {      Bundle params = new Bundle();     params.putString("name", name);     params.putString("caption", caption);     params.putString("description", desc);     params.putString("link", link);     //params.putString("picture", "https://www.facebook.com/photo.php?fbid=10203610233686079&set=a.10203610230766006.1073741829.1523023247&type=1&theater");     params.putString("picture", picture);      WebDialog feedDialog = (         new WebDialog.FeedDialogBuilder(MainActivity.this,             Session.getActiveSession(),             params))         .setOnCompleteListener(new OnCompleteListener() {              @Override             public void onComplete(Bundle values,                 FacebookException error) {                 if (error == null) {                     // When the story is posted, echo the success                     // and the post Id.                     final String postId = values.getString("post_id");                     if (postId != null) {                         Toast.makeText(MainActivity.this,                             "Successfuly posted!",                             Toast.LENGTH_SHORT).show();                     } else {                         // User clicked the Cancel button                         Toast.makeText(MainActivity.this,                              "Publish cancelled",                              Toast.LENGTH_SHORT).show();                     }                 } else if (error instanceof FacebookOperationCanceledException) {                     // User clicked the "x" button                     Toast.makeText(MainActivity.this,                          "Publish cancelled",                          Toast.LENGTH_SHORT).show();                 } else {                     // Generic, ex: network error                     Toast.makeText(MainActivity.this,                         "Error posting story",                          Toast.LENGTH_SHORT).show();                 }             }            })         .build();         feedDialog.show();      }      @SuppressWarnings("unused")     private boolean isSubsetOf(Collection<String> subset, Collection<String> superset) {         for (String string : subset) {             if (!superset.contains(string)) {                 return false;             }         }         return true;      }      } 

Answer 1

For class extending Activity :

getActionBar().hide(); getActionBar().show(); 

For class extending AppCompatActivity :

getSupportActionBar().hide(); getSupportActionBar().show(); 

Answer 2

Very simple.

getActionbar().hide(); getActionbar().show();