Flèche arrière Android dans la barre d'outils (AppCompatActivity)

J'en veux pour preuve le bouton flèche de retour dans mon application, mais l'application se bloque quand j'ai mis ceci dans mon code:

getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);

style.xml

 <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <item name="colorPrimary">@color/PrimaryColor</item>
    <item name="colorPrimaryDark">@color/PrimaryColorDark</item>
    <item name="colorAccent">@color/PrimaryColor</item>
    <item name="colorControlHighlight">@color/ControlHighlight</item>
    <item name="android:statusBarColor" tools:targetApi="21">@android:color/transparent</item>
</style>


<style name="ActionBarPopupThemeOverlay" parent="ThemeOverlay.AppCompat.Light" >
    <item name="android:textColor">#000000</item>
</style>


<style name="MyCustomTabLayout" parent="Widget.Design.TabLayout">
    <item name="tabIndicatorColor">#FFFFFF</item>
    <item name="tabIndicatorHeight">3dp</item>
    <item name="tabTextAppearance">@style/MyCustomTabTextAppearance</item>
</style>


<style name="MyCustomTabTextAppearance" parent="TextAppearance.Design.Tab">
    <item name="android:textColor">#FFFFFF</item>
</style>

toolbar.xml

<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_height="@dimen/abc_action_bar_default_height_material"
android:elevation="0dp"
android:layout_width="match_parent"
android:id="@+id/toolbar"
android:background="@color/PrimaryColor"
app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
app:popupTheme="@style/ActionBarPopupThemeOverlay"/>

Classe (ne pas Fragmenter):

public class WebViewCanale extends AppCompatActivity {

    Toolbar toolbar;
    TextView textView;
    WebView webView;
    ProgressBar progressBar;

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

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setDisplayShowHomeEnabled(true);

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


        //FindViewById
        webView = (WebView) findViewById(R.id.webview);
        textView = (TextView) findViewById(R.id.textView);
        progressBar = (ProgressBar) findViewById(R.id.progressBar);

        //Impostazioni WebView
        WebSettings webSettings = webView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webSettings.setLoadsImagesAutomatically(true);
        webView.loadUrl(this.getIntent().getDataString());
        webView.getSettings().setCacheMode(WebSettings.LOAD_NO_CACHE);
        webView.getSettings().setAppCacheEnabled(false);

        //Titolo Toolbar
        webView.setWebChromeClient(new WebChromeClient() {
            @Override
            public void onReceivedTitle(WebView view, String title) {
                super.onReceivedTitle(view, title);
                if (!TextUtils.isEmpty(title)) {
                    WebViewCanale.this.setTitle(title);
                }
            }
        });
    }
}

source d'informationauteur Simone Varletta