使用 PreferenceFragment 构建的设置页面中的工具栏

Toolbar in Settings page built with PreferenceFragment

我使用 this 指南为我的应用构建了一个设置 activity/screen。示例代码如下。 我缺少什么才能向这个新的 activity 添加一个左侧带有后退箭头的工具栏?

AndroidManifest.xml

....
<activity
    android:name=".SettingsActivity"
    android:label="Settings"
    android:launchMode="singleTask"
    android:theme="@style/AppTheme.NoActionBar"/>
....

preferences.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<CheckBoxPreference
    android:key="pref_sync"
    android:title="@string/pref_sync"
    android:summary="@string/pref_sync_summ"
    android:defaultValue="true" />
<ListPreference
    android:dependency="pref_sync"
    android:key="pref_syncConnectionType"
    android:title="@string/pref_syncConnectionType"
    android:dialogTitle="@string/pref_syncConnectionType"
    android:entries="@array/pref_syncConnectionTypes_entries"
    android:entryValues="@array/pref_syncConnectionTypes_values"
    android:defaultValue="@string/pref_syncConnectionTypes_default" />
</PreferenceScreen>

SettingsFragment.java

public static class SettingsFragment extends PreferenceFragment {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Load the preferences from an XML resource
        addPreferencesFromResource(R.xml.preferences);
    }
    ...
}

SettingsActivity.java

public class SettingsActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Display the fragment as the main content.
        getFragmentManager().beginTransaction()
                .replace(android.R.id.content, new SettingsFragment())
                .commit();
    }
}

您必须在 activity 布局中包含一个工具栏。例如:

activity_main.xml

 <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".activities.SettingsActivity">

        <include
            android:id="@+id/app_bar"
            layout="@layout/app_bar" />

        <FrameLayout
            android:id="@+id/container"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_below="@+id/app_bar"/>

    </RelativeLayout>

app_bar.xml

<android.support.v7.widget.Toolbar
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="?attr/colorPrimary"
    app:popupTheme="@style/AppTheme.PopupOverlay" />

在您的 Activity.onCreate() 中获取工具栏并设置主页按钮(小箭头):

        Toolbar toolbar = (Toolbar)findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setHomeButtonEnabled(true);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

将 SettingsActivity 设置为父 MainActivity 的子项:

<activity
    android:name=".activities.SettingsActivity"
    android:label="@string/title_activity_main"
    android:parentActivityName=".activities.MainActivity" />

那会给你那个小箭头。

另外,这样做:

public class SettingsActivity extends AppCompatActivity

不是这个:

public class SettingsActivity extends Activity

为了使用支持库。