报错如下：

This Activity already has an action bar supplied by the window decor

up vote java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tyczj.weddingalbum/com.xxx.xxx.MainActivity}: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead. at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) at android.app.ActivityThread.access$600(ActivityThread.java:141) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:137) at android.app.ActivityThread.main(ActivityThread.java:5039) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead. at android.support.v7.app.ActionBarActivityDelegateBase.setSupportActionBar(ActionBarActivityDelegateBase.java:165) at android.support.v7.app.ActionBarActivity.setSupportActionBar(ActionBarActivity.java:92) at com.xxx.xxx.MainActivity.onCreate(MainActivity.java:113) at android.app.Activity.performCreate(Activity.java:5104) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)             at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)             at android.app.ActivityThread.access$600(ActivityThread.java:141)             at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)             at android.os.Handler.dispatchMessage(Handler.java:99)             at android.os.Looper.loop(Looper.java:137)             at android.app.ActivityThread.main(ActivityThread.java:5039)             at java.lang.reflect.Method.invokeNative(Native Method)             at java.lang.reflect.Method.invoke(Method.java:511)             at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)             at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)             at dalvik.system.NativeStart.main(Native Method)

主题：

<style name="AppCompatTheme" parent="@style/Theme.AppCompat.Light"> <item name="android:windowActionBar">false</item> </style> <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar"> <!-- Customize your theme here. --> <item name="colorPrimary">@color/colorPrimary</item> <item name="colorPrimaryDark">@color/colorPrimaryDark</item> <item name="colorAccent">@color/colorAccent</item> </style>

manifest

<activity android:name=".MainActivity" android:windowSoftInputMode="adjustResize|stateHidden" android:theme="@style/AppCompatTheme" android:screenOrientation="portrait"/>

MainActivity 继承 GooglePlayServiceActivity 

<activity android:name=".GooglePlayServicesActivity" android:label="@string/title_activity_google_play_services" android:theme="@style/AppCompatTheme">

解决： up vote 310 down vote accepted

I think you're developing for Android Lollipop, but anyway include this line:

<item name="windowActionBar">false</item>

to your theme declaration inside of your app/src/main/res/values/styles.xml.

Also, if you're using AppCompatActivity support library of version 22.1 or greater, add this line:

<item name="windowNoTitle">true</item>

values 里的 styles  修改成这样:

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar"> <!-- Customize your theme here. --> <item name="colorPrimary">@color/colorPrimary</item> <item name="colorPrimaryDark">@color/colorPrimaryDark</item> <item name="colorAccent">@color/colorAccent</item> <item name="windowActionBar">false</item> <item name="windowNoTitle">true</item> </style>