动作栏中项目标题的动态更改

Question

What I am trying to do is: change the title of an item in Action Bar from onClick method. Code of onCreateOptionsMenu :

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu items for use in the action bar
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.option_menu, menu);    
    return super.onCreateOptionsMenu(menu);
}

My option_menu.xml of menu:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:id="@+id/state"
      android:title="@string/title_not_connected"
      android:showAsAction="ifRoom" />
</menu>

The title should change from onClick method in class below:

@SuppressLint("ValidFragment")
public class ReceiveSectionFragment extends Fragment {
        public NotificationCenter mNotificationCenter;

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            final View rootView = inflater.inflate(R.layout.receive, container, false);
            mNotificationCenter = new NotificationCenter();
            rootView.findViewById(R.id.bt_server_start)
            .setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    MenuItem item = (MenuItem) menu.findItem(R.id.state);
                    item.setTitle(TAG);
                }
            });
    }
}

As you can see I am trying to find this item in menu by Id but I am getting this error: The method findItem(int) is undefined for the type R.menu . I am using fragments and ReceiveSectionFragment uses R.layout.receive layout.

How can I deal with this problem? Possibly, I am doing it all wrong by using wrong methods.

I am not using ActionBar Sherlock.

Answer 1

You have to call InvalidateOptionsMenu when you want to make changes to the ActionBar menu.

You then override onCreateOptionsMenu to rebuild your menu with your changes in place. You cannot edit a menu outside of the methods provided for building menus.

Every time you call InvalidateOptionsMenu your menu will be rebuilt by the onCreateOptionsMenu method so you need to make all of your changes there.

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

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

This is true whether you are using ActionBarSherlock or not.

eg:

Set a variable to hold the title

String MyMenuTitle = "Default Menu";

Your OnClick

public void onClick(View view) {
    MyMenuTitle = "My New Menu Title";
}

Your Menu Building Code.

@Override
public boolean onCreateOptionsMenu(Menu menu) {

    getMenuInflater().inflate(R.menu.option_menu, menu); 

    MenuItem item = menu.findItem(R.id.state);
    item.setTitle(MyMenuTitle);

    return super.onCreateOptionsMenu(menu);
}

Answer 2

You should insert the following lines in the fragment in which you want to hide the menu.

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    super.onCreateOptionsMenu(menu, inflater);

    MenuItem item = (MenuItem) menu.findItem(R.id.your_action);
    item.setVisible(false);
}

Answer 3

There is another way to do this without InvalidateOptionsMenu..

first declare the MenuItem as static before the onCreate Method..

  static MenuItem item;

Then initialize handler in onCreateOptionsMenu

  @Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    item = menu.findItem(R.id.state);

    return true;
}

Finally use setTitle whenever you want to change your title...

 item.setTitle("your title");

I hope this helps...

Answer 4

Its Working

static MenuItem item; // Define Global Variable

 @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        super.onCreateOptionsMenu(menu, inflater);
        menu.clear();
        inflater.inflate(R.menu.minu_filter, menu);
        menu.findItem(action_enter_manually).setVisible(true);
        // allocation id 
        item = menu.findItem(R.id.action_enter_manually);
    }

call Where item.setTitle("your title");