Actionbar items are duplicating

问题:

I have Action Bar in my application. I am adding action items using menu.xml. I am using action bar-compat as my support library. I observed a weird issue where my action items are getting duplicated.

I am finding this issue randomly when leave my device idle or work with other applications. Please find the screen shot and my code below:

private LoginWebActivity mContext;
private final String TAG = "LoginFragment";

// for metrics
private String mPageNameSignIn = "signin";

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    mView = inflater.inflate(R.layout.webview, container, false);

    return mView;
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    mContext = (LoginWebActivity) getActivity();
    initFragment();

}

@Override
public void onResume() {

    super.onResume();
}

/**
 * Initialises the views and variables of the fragment.
 */
@SuppressLint({ "JavascriptInterface", "SetJavaScriptEnabled" })
protected void initFragment() {


    mWebView = (WebView) mView.findViewById(R.id.webView);
    Bundle b = mContext.getIntent().getExtras();
    if (b != null) {
        mUrl = b.getString(Constants.EXTRA_WEB_LOGIN_URL);
    }
    super.initFragment();

    setHasOptionsMenu(true);
}

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

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Navigate
    switch (item.getItemId()) {
    case R.id.menu_item_signup:
        mContext.onSignUpClick();
        break;
    case android.R.id.home:
        if (!goBack())
            getActivity().finish();
    default:
        break;
    }
    return super.onOptionsItemSelected(item);
}

My XML :

<?xml version="1.0" encoding="utf-8"?>

<item
    android:id="@+id/menu_item_signup"
    allergy:showAsAction="ifRoom"
    android:title="@string/sign_up">
</item>

回答1:

You must clear your menu object before adding items. I had the same problem and this was the best solution that I've found.

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    menu.clear();
    inflater.inflate(R.menu.signin, menu);
    super.onCreateOptionsMenu(menu, inflater);
}

回答2:

Pretty late to this party, but for anyone that comes across this via the Google like I did, here's the real problem.

You didn't post your Activity code that's creating the Fragment, but I will venture to guess that it looks something like this:

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_layout);
        Fragment fragment = ...
        getSupportFragmentManager()
            .beginTransaction()
            .add(R.id.fragment_container, fragment)
            .commit();
    }

The problem with this is that when the activity goes through its lifecycle (which would happen "when leave my device idle or work with other applications", as you say), the system will save and restore the state of fragments for you. But with this code, you also are adding a new fragment to your Activity, so you end up with multiple fragments running in your activity, each adding an item to the menu.

While the posted workaround will address the duplicate menu entries issue, it would leave these extra fragment instances lying around, which is obviously not what you want.

The correct fix is a simple null check:

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_layout);

        if (savedInstanceState == null) {
            Fragment fragment = ...
            getSupportFragmentManager()
                .beginTransaction()
                .add(R.id.fragment_container, fragment)
                .commit();
        }
    }

Since the system will indicate the activity is being recreated with a non-null Bundle for the savedInstanceState parameter, you check this to determine whether you should be creating and adding a new fragment.

Hope that helps.

回答3:

i used Renan Bandeira's great solution and i had some error so i changed it a little bit and worked for me too . then I'm sharing my experience : maybe it become helpful again all credit goes to him for great solution .

@Override
    public void onCreateOptionsMenu(Menu menu ) {
       menu.clear();
       MenuInflater inflater = getMenuInflater();    
       inflater.inflate(R.menu."your current activity name ", menu);
    return true;
}

回答4:

I facing the same problem and exactly as state by @Szymon "I add menu option from the fragment, I create multiple fragments?" So my solution was look like below.

onCreate :

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    menu.clear();
    inflater.inflate(R.menu.menu, menu);
    menu.findItem(R.id.action_one).setVisible(true);
    menu.findItem(R.id.action_two).setVisible(false);
    super.onCreateOptionsMenu(menu, inflater);
}

onPrepare :

@Override
public void onPrepareOptionsMenu(Menu menu) {
    if (isAdded()
            && !isDetached()
            && isVisible()
            && !isRemoving()
            )
    {
        // show the menu
        if (menu.findItem(R.id.action_one).isVisible())
            menu.findItem(R.id.action_one).setVisible(true);
        // hide the menu
        if (menu.findItem(R.id.action_two).isVisible())
            menu.findItem(R.id.action_two).setVisible(false);
    }
}

回答5:

You should use the following method instead and you will not see the duplicates anymore (notice that it has only a Menu object as argument)

  @Override
    public boolean onCreateOptionsMenu( Menu menu )
    {
        getMenuInflater().inflate( R.menu.main_activity_menu, menu );
        return true;
    }