OnToolBar there is a navigation icon at left side
Toolbar toolbar = (Toolbar) findViewById(R.id.tool_bar);
toolbar.setTitle(getResources().getString(R.string.title_activity_select_event));
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
By using this at left side navigation icon appear and on navigation icon click it call parent activity.
and in manifest we can notify system about parent activity.
<activity
android:name=".CategoryCloudSelectActivity"
android:parentActivityName=".EventSelectionActivity"
android:screenOrientation="portrait" />