隐藏标题栏/操作栏的最佳方式？

Question

我想在横向模式下隐藏标题栏（actionbar），所以我使用这个代码：

if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
           requestWindowFeature(Window.FEATURE_NO_TITLE);
        }
        setContentView(R.layout.activity_view_entries);

这适用于大多数设备，但它会使应用程序在 HTC Sensation XL (http://www.gsmarena.com/htc_sensation_xl-4161.php) 上崩溃。

这是 style.xml（我在清单中使用 CustomActionBarTheme）：

<style name="CustomActionBarTheme"
           parent="@android:style/Theme.Holo.Light.DarkActionBar">
        <item name="android:actionBarStyle">@style/MyActionBar</item>
        <item name="android:dropDownSpinnerStyle">@style/SpinnerAppTheme</item>
        <item name="android:editTextBackground">@drawable/apptheme_edit_text_holo_light</item>
    </style>

    <style name="MyActionBar"
           parent="@android:style/Widget.Holo.Light.ActionBar.Solid.Inverse">
        <item name="android:background">@color/orange</item>
        <item name="android:icon">@drawable/ic_action_logo</item>
    </style>

这是崩溃日志：

03-24 14:51:39.129 E/AndroidRuntime(13890): FATAL EXCEPTION: main
03-24 14:51:39.129 E/AndroidRuntime(13890): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myprojects.tib.abstimetracker/com.myprojects.tib.abstimetracker.activities.ViewEntries}: java.lang.NullPointerException
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2194)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2229)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3791)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.app.ActivityThread.access0(ActivityThread.java:139)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1265)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.os.Looper.loop(Looper.java:154)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.app.ActivityThread.main(ActivityThread.java:4945)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at java.lang.reflect.Method.invokeNative(Native Method)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at java.lang.reflect.Method.invoke(Method.java:511)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at dalvik.system.NativeStart.main(Native Method)
03-24 14:51:39.129 E/AndroidRuntime(13890): Caused by: **java.lang.NullPointerException**
03-24 14:51:39.129 E/AndroidRuntime(13890):     at com.android.internal.policy.impl.PhoneWindow$PanelFeatureState.onRestoreInstanceState(PhoneWindow.java:3493)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at com.android.internal.policy.impl.PhoneWindow.restorePanelState(PhoneWindow.java:1733)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at com.android.internal.policy.impl.PhoneWindow.restoreHierarchyState(PhoneWindow.java:1689)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.app.Activity.onRestoreInstanceState(Activity.java:939)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.app.Activity.performRestoreInstanceState(Activity.java:911)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.app.Instrumentation.callActivityOnRestoreInstanceState(Instrumentation.java:1132)
03-24 14:51:39.129 E/AndroidRuntime(13890):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2172)
03-24 14:51:39.129 E/AndroidRuntime(13890):     ... 12 more

我的问题是：谁能告诉我应该检查什么是否为空以及标题栏和操作栏之间有什么区别？

Answer 1

标题栏是 UI 的一小部分，您可以为其提供一些文本和颜色。您会在很多 Android 2.0 应用程序中看到它。参见 https://androidproblem.wordpress.com/category/title-bar/

Actionbar 是带有后退导航等按钮的栏。如果可以选择，您可以使用它而不是 Titlebar。参见 https://developer.android.com/guide/topics/ui/actionbar.html

要检查空值，您可以找到哪一行给您一个空指针异常，然后您可以添加一个 if 检查，如下所示：

if ( x != null){

//perform actual action

}

else {

// Display a toast or some thing and perform a graceful exit from the application or stay in the application.

}

希望这对您有所帮助。差异基于之前的 SO 答案。

隐藏标题栏/操作栏的最佳方式？

Best way to hide titlebar / actionbar?

android

android-actionbar