AppCompatPreferenceActivity up button not working

android

Solution

You can also just use `finish()` when the back button is pressed:

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == android.R.id.home) {
        finish();
        return true;
    }
    return super.onOptionsItemSelected(item);
}

Problem

I'm trying to make an activity which extends AppCompatPreferenceActivity and implements an up button in the action bar. Visually everything looks fine, but the up button doesn't respond to touch events. The following is my java and xml code: PrefrencesDisplayActivity.java ``` package com.example.matthew.testsettings; import android.support.design.widget.AppBarLayout; import android.support.design.widget.CoordinatorLayout; import android.support.v7.widget.Toolbar; import android.widget.ListView; import android.widget.RelativeLayout; import java.util.List; public class PreferencesDisplayActivity extends AppCompatPreferenceActivity { CoordinatorLayout activityRoot; AppBarLayout appBarLayout; Toolbar toolbar; RelativeLayout contentRoot; ListView preferencesList; @Override public void onBuildHeaders(List<Header> target) { loadHeadersFromResource(R.xml.preferences, target); initialiseUI(); } private void initialiseUI() { // Inflate activity layout from xml setContentView(R.layout.activity_preferences_display); // Get handles to UI elements activityRoot = (CoordinatorLayout) findViewById(R.id.prefDisplay_activity_root); appBarLayout = (AppBarLayout) findViewById(R.id.prefdisplay_activity_appBarLayout); toolbar = (Toolbar) findViewById(R.id.prefDisplay_activity_toolbar); contentRoot = (RelativeLayout) findViewById(R.id.prefDisplay_content_root); preferencesList = (ListView) findViewById(android.R.id.list); // Create and configure action bar setSupportActionBar(toolbar); getSupportActionBar().setDisplayHomeAsUpEnabled(true); } } ``` activity_prefrences_display.xml ``` <?xml version="1.0" encoding="utf-8"?> <android.support.design.widget.CoordinatorLayout android:theme="@style/AppTheme.NoActionBar" android:id="@+id/prefDisplay_activity_root" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:fitsSystemWindows="true" tools:context="com.example.matthew.testsettings.PreferencesDisplayActivity"> <android.support.design.widget.AppBarLayout android:id="@+id/prefdisplay_activity_appBarLayout" android:layout_height="wrap_content" android:layout_width="match_parent" android:theme="@style/AppTheme.AppBarOverlay"> <android.support.v7.widget.Toolbar android:id="@+id/prefDisplay_activity_toolbar" android:layout_width="match_parent" android:layout_height="?attr/actionBarSize" android:background="?attr/colorPrimary" app:popupTheme="@style/AppTheme.PopupOverlay"/> </android.support.design.widget.AppBarLayout> <include layout="@layout/content_preferences_display"/> </android.support.design.widget.CoordinatorLayout> ``` content_preferences_display.xml ``` <?xml version="1.0" encoding="utf-8"?> <RelativeLayout android:id="@+id/prefDisplay_content_root" xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:paddingBottom="@dimen/activity_vertical_margin" app:layout_behavior="@string/appbar_scrolling_view_behavior" tools:showIn="@layout/activity_preferences_display" tools:context="com.example.matthew.testsettings.PreferencesDisplayActivity"> <ListView android:id="@id/android:list" android:layout_width="fill_parent" android:layout_height="fill_parent"/> </RelativeLayout> ``` AndroidManifest.xml ``` <?xml version="1.0" encoding="utf-8"?> <manifest package="com.example.matthew.testsettings" xmlns:android="http://schemas.android.com/apk/res/android"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity" android:label="@string/app_name" android:theme="@style/AppTheme.NoActionBar"> <intent-filter> <action android:name="android.intent.action.MAIN"/> <category android:name="android.intent.category.LAUNCHER"/> </intent-filter> </activity> <activity android:name=".PreferencesDisplayActivity" android:label="@string/title_activity_preferences_display" android:parentActivityName="com.example.matthew.testsettings.MainActivity" android:theme="@style/AppTheme.NoActionBar"> <meta-data android:name="android.support.PARENT_ACTIVITY" android:value="com.example.matthew.testsettings.MainActivity"/> </activity> </application> </manifest> ``` When I open the app and navigate to the preferences activity, the screen looks as it should but pressing the up button does nothing. Can anyone see my mistake?

Original source