showAsAction = “always” is ignored in Toolbar

问题

After switching to toolbar there is a problem with menu icons. Although I set for a menu item android:showAsAction="always" it does not show the icon, I can only find it clicking on the popup icon.

This is myActivity

public class myActivity extends AppCompatActivity{
  .........
  public void onCreate(....){
     .............
     Toolbar toolbar = (Toolbar) findViewById(....); 
     setSupportActionBar(toolbar);
  }
  ............
  public boolean onCreateOptionsMenu(Menu menu{
            getMenuInflater().inflate(R.menu.menu, menu);

            return super.onCreateOptionsMenu(menu);
  }
  .............
}

menu.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android">

     <item
       android:id="@+id/settings"
       android:icon="@drawable/settings" 
       android:title="settings"
       android:showAsAction="always"
     />
    <item
       android:id="@+id/help"
       android:icon="@drawable/help" 
       android:title="help"
       android:showAsAction="never"
     />
</menu>

Both settings and help icons are only in popup menu. So how to show settings icon on toolbar?

回答1:

Replace android:showAsAction with app:showAsAction. You will also need to add xmlns:app="http://schemas.android.com/apk/res-auto" alongside your existing xmlns item in your root element.

回答2:

With AppCompat there is a little change. If you are running lint it will complain about it. Type this:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto">
<item
    android:id="@+id/someId"
    android:title="@string/someText"
    app:showAsAction="always"/>
</menu>

You need to declare the "app" namespace and reference it.

来源：https://stackoverflow.com/questions/32009628/showasaction-always-is-ignored-in-toolbar