配置：
中设置theme为
<application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:theme="@android:style/Theme.Light.NoTitleBar" android:label="@string/app_name" >
报错信息：
09-20 10:31:58.185 1392-1392/? E/AndroidRuntime﹕ FATAL EXCEPTION: main Process: networkimageviewer.com.myapplication, PID: 1392 java.lang.RuntimeException: Unable to start activity ComponentInfo{networkimageviewer.com.myapplication/networkimageviewer.com.myapplication.WelcomeActivity}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity. at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2192) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2241) at android.app.ActivityThread.access$800(ActivityThread.java:141) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1204) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5049) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity. at android.support.v7.app.AppCompatDelegateImplV7.createSubDecor(AppCompatDelegateImplV7.java:309) at android.support.v7.app.AppCompatDelegateImplV7.ensureSubDecor(AppCompatDelegateImplV7.java:278) at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:252) at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:109) at networkimageviewer.com.myapplication.WelcomeActivity.onCreate(WelcomeActivity.java:22) at android.app.Activity.performCreate(Activity.java:5249) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2156) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2241) at android.app.ActivityThread.access$800(ActivityThread.java:141) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1204) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:136) at android.app.ActivityThread.main(ActivityThread.java:5049) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:515) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609) at dalvik.system.NativeStart.main(Native Method)
解决办法：
To simply add ActionBar Compat your activity or application should use @style/Theme.AppCompat theme in AndroidManifest.xml like this:
<application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:theme="@style/Theme.AppCompat.Light.NoActionBar" android:label="@string/app_name" >
http://stackoverflow.com/questions/18063395/actionbarcompat-java-lang-illegalstateexception-you-need-to-use-a-theme-appcom
