Change icons in ActionBar dynamically

Question

I have an Activity which has an ActionBar but I need to change the icons on the ActionBar dynamically, I have a pause and a play button and I need to replace the play button with the pause button as the user click on it. I have searched and I found it:

@Override public boolean onCreateOptionsMenu(Menu menu) {     if(DEBUG) Log.i("onCreateOptionsMenu()", "onCreateOptionsMenu() -> LogicAnalizerView");     //menu.add("").setIcon(R.drawable.pause).setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);     MenuInflater inflater = getMenuInflater();     inflater.inflate(R.menu.actionbarlogic, menu);     menu.removeItem(R.id.pauseLogic);      return true; } 

So in this way I remove the Pause button and I can add it too, but it only happen when I start the Activity and the ActionBar is drawn. How can I force to redraw the ActionBar? Also, on this way the whole ActionBar is redrawn. Is that right? Is any way to redraw only the button/icon I want?

Thank you :)

Answer 1

You'll have to save off a reference to the MenuItem after doing the inflation. So something like the following:

public boolean onCreateOptionsMenu( Menu menu ) {     MenuInflater inflater = getMenuInflater();     inflater.inflate( R.menu.actionbarlogic, menu );     playMenu = menu.findItem(R.id.playMenu);     updatePlayStatus();     return menu; }  public void updatePlayStatus() {     if( playService.isConnected() ) {         playService.isPlaying() ? playMenu.setIcon(R.drawable.pause) : playMenu.setIcon(R.drawable.play);     } } 

Then you can refer to the playMenu anytime. So you can modify the item as say your player finishes playing and should go back to a play icon.

Answer 2

Instead of removing them, you could just hide the button you don't want displayed.

For example:

private boolean isPlaying; MenuItem mPlayMenuItem; MenuItem mPauseMenuItem;  @Override public boolean onCreateOptionsMenu(Menu menu) {     // Inflate the menu items for use in the action bar     MenuInflater inflater = getMenuInflater();     inflater.inflate(R.menu.actionbarlogic, menu);      mPlayMenuItem = menu.findItem(R.id.action_play);     mPauseMenuItem = menu.findItem(R.id.action_pause);      return super.onCreateOptionsMenu(menu);  }  @Override public boolean onOptionsItemSelected(MenuItem item) {      switch (item.getItemId()) {         case R.id.action_play:             isPlaying = true;             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {                 this.invalidateOptionsMenu();             }             return true;         case R.id.action_pause:             isPlaying = false;             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {                 this.invalidateOptionsMenu();             }             return true;         default:             return super.onOptionsItemSelected(item);     } }    @Override public boolean onPrepareOptionsMenu (Menu menu) {     super.onPrepareOptionsMenu(menu);      if (isPlaying) {         mPlayMenuItem.setVisible(false); // hide play button         mPauseMenuItem.setVisible(true); // show the pause button     } else if (!isPlaying) {         mPlayMenuItem.setVisible(true); // show play button         mPauseMenuItem.setVisible(false); // hide the pause button     }      return true; } 

Just a note, this:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {      this.invalidateOptionsMenu(); } 

is required to update the action bar. After 3.0 devices, the action bar does not automatically update itself. So, you have to manually tell it to call the "OnPrepareOptionsMenu(Menu)" so that it will refresh the items by calling the "Activity.invalidateOptionsMenu()".

Hope this helps!

Reference: http://developer.android.com/reference/android/app/Activity.html#onPrepareOptionsMenu(android.view.Menu)

http://developer.android.com/reference/android/support/v4/app/ActivityCompat.html#invalidateOptionsMenu(android.app.Activity)