[android-developers] Problem with Adding Action Buttons in the Action Bar Using Pager and Fragments

[Mark Phillips]

My app has three tabs and I am using a pager to switch between the tabs.
Each tab has its own fragment. I added the Settings and Help action buttons
to the action bar in the main Activity using the OptionsMenu methods. I now
want to add a new action button to the action bar, but just for the first
tab and first fragment, and I don't want it to appear on the other
fragments when they are displayed in their tabs.

I have this layout for the main menu that is created in the main activity -

<menu xmlns:android="http://schemas.android.com/apk/res/android";
    xmlns:app="http://schemas.android.com/apk/res-auto";
    xmlns:tools="http://schemas.android.com/tools";
    tools:context=".MainActivity">

    <item android:id="@+id/action_settings"
        android:title="@string/action_settings"
        android:orderInCategory="100" app:showAsAction="never" />

    <item android:id="@+id/help"
        android:title="@string/help"
        android:orderInCategory="100" app:showAsAction="never" />
</menu>

This menu displays correctly and works as expected.

I have another menu, menu_prelaunch_fragment for the first fragment -

<menu xmlns:android="http://schemas.android.com/apk/res/android";
    xmlns:app="http://schemas.android.com/apk/res-auto";>

    <item android:id="@+id/clear_form"
        android:title="Clear"
        android:icon="@drawable/ic_action_action_delete"
        app:showAsAction="always" />
</menu>

and I add it to the action bar using the following code in the first
fragment -

@Override
public void onCreate(Bundle savedInstance) {
    Log.d(TAG, "onCreate");
    super.onCreate(savedInstance);
    setHasOptionsMenu(true);
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflator) {
    Log.d(TAG, "onCreateOptionsMenu");
    inflator.inflate(R.menu.menu_prelaunch_fragment, menu);
    super.onCreateOptionsMenu(menu, inflator);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    Log.d(TAG, "onOptionsItemSelected");
    if (item.getItemId() == R.id.clear_form)
        clearFragmentData();
    return super.onOptionsItemSelected(item);
}

The problem is that this added button does not go away when I go to the
other fragments on the other pages/tabs. The other fragments do not have
any options menu code in them.

I then added this code to the other fragments to remove the one button.

@Override
public void onCreate(Bundle savedInstanceState) {
    Log.d(TAG, "onCreate");
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
}

@Override
public void onPrepareOptionsMenu (Menu menu) {
    menu.findItem(R.id.clear_form).setVisible(false);
    super.onPrepareOptionsMenu(menu);
}

But now the clear button does not appear in the action bar regardless of
what tabs are selected.

How do I add an action button to the action bar just for one tab (ie
fragment) in my three tab (ie three fragment) app? It should only appear
when that tab (fragment) is selected (displayed).

Thanks!

Mark

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