设置Android的ActionBar菜单项

Question

I am just getting started with Android. I want to add an ActionBar menu to my small tip calculator application. I have set up the menu xml file. When I run the application on my mobile device, the part where the menu is supposed to appear, is blank.

My onCreate Method does not have the setActionBar() method, so I think the problem could lie there??

Here is the code for my onCreate Method:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    serviceLevelSpinner = (Spinner) findViewById(R.id.serviceLevelSpinner);

Menu.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/tools">
<item android:id = "@+id/aboutLink" android:title = "@string/applicationAbout" app:showAsAction = "always" android:icon = "@drawable/ic_mymenu"/>
</menu>

Answer 1

Check whether you extends the ActionbarActivity to make the Activity or simple Activity . To has the functionality of Actionbar you need to extends the ActionbarActivity . And then your code will work fine with the menu items.

Answer 2

First ensure that your Activity extends AppCompatActivity . Next, add a Toolbar to your Activity's layout file. Call the setSupportActionBar(toolbar) method in onCreate . The parameter used should be an instance of the Toolbar from your layout.

Note that in your styles.xml file, you have to set the windowActionBar item to false or use a theme with parent="Theme.AppCompat.NoActionBar" to avoid errors from duplicate toolbars.