问Android:返回导航到尚未调用的活动

EN

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="test.com.testlauncher">

    <application
        android:theme="@style/Theme.AppCompat.Light.NoActionBar">

        <activity android:name=".C">
        </activity>


        <activity android:name=".A" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
        </activity>

        <activity android:name=".B"
            android:parentActivityName=".C">

            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="test.com.testlauncher.C" />
        </activity>

    </application>

</manifest>

public class B extends AppCompatActivity {

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

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar_main);
        setSupportActionBar(toolbar);

        ActionBar actionBar = getSupportActionBar();

        actionBar.setTitle("Back");

        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setDisplayShowHomeEnabled(true);

    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar_main"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        android:elevation="0dp"
        android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
        app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/>

</LinearLayout>