show icon in actionbar/toolbar with AppCompat-v7 21

Question

getSupportActionBar().setDisplayShowHomeEnabled(true);

along with

getSupportActionBar().setIcon(R.drawable.ic_launcher);

In modern Android UIs developers should lean more on a visually distinct color scheme for toolbars than on their application icon. The use of application icon plus title as a standard layout is discouraged on API 21 devices and newer.

If you disagree you can try with:

To create the toolbar in XML:

<android.support.v7.widget.Toolbar  
    android:id="@+id/my_awesome_toolbar"
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    android:minHeight="?attr/actionBarSize"
    android:background="?attr/colorPrimary" />

In your activity:

@Override
public void onCreate(Bundle savedInstanceState) {  
    super.onCreate(savedInstanceState);
    setContentView(R.layout.my_layout);

    Toolbar toolbar = (Toolbar) findViewById(R.id.my_awesome_toolbar);
    setSupportActionBar(toolbar);
}

Use the setLogo() method to set the icon. Code source.

This worked for me:

    getSupportActionBar().setHomeButtonEnabled(true);
    getSupportActionBar().setDisplayShowHomeEnabled(true);
    getSupportActionBar().setDisplayUseLogoEnabled(true);
    getSupportActionBar().setLogo(R.drawable.ic_logo);
    getSupportActionBar().setDisplayShowTitleEnabled(false); //optional

as well as:

    getSupportActionBar().setHomeButtonEnabled(true);
    getSupportActionBar().setDisplayShowHomeEnabled(true);
    getSupportActionBar().setIcon(R.drawable.ic_logo); //also displays wide logo
    getSupportActionBar().setDisplayShowTitleEnabled(false); //optional

simplest thing to do; just add:

app:navigationIcon="@drawable/ic_action_navigation_menu">

to the <android.support.v7.widget.Toolbar tag

where @drawable/ic_action_navigation_menu is the name of icon

A better way for setting multiple options:

setIcon/setLogo method will only work if you have set DisplayOptions Try this -

actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_HOME | ActionBar.DISPLAY_SHOW_TITLE);
actionBar.setIcon(R.drawable.ic_launcher);

You can also set options for displaying LOGO(just add constant ActionBar.DISPLAY_USE_LOGO). More information - displayOptions

Try using:

ActionBar ab = getSupportActionBar();
ab.setHomeButtonEnabled(true);
ab.setDisplayUseLogoEnabled(true);
ab.setLogo(R.drawable.ic_launcher);