“You need to use a Theme.AppCompat theme (or descendant) with this activity.”错误

学习Android的hello Android时，遇到一个主题相关的错误如下：

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.soosmart.hellomobile/com.soosmart.hellomobile.AboutActivity}: 
java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.

at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
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:343)
at android.support.v7.app.AppCompatDelegateImplV7.ensureSubDecor(AppCompatDelegateImplV7.java:312)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:277)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
at com.soosmart.hellomobile.AboutActivity.onCreate(AboutActivity.java:11)
at android.app.Activity.performCreate(Activity.java:5133)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261) 
at android.app.ActivityThread.access$600(ActivityThread.java:141) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:137) 
at android.app.ActivityThread.main(ActivityThread.java:5103) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:525)                                                                

如何理解“java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.”

Stackoverflow上的解释：

The reason you are having this problem is because the activity you are trying to apply the dialog theme to is extending ActionBarActivity which requires the AppCompat theme to be applied.

Change the Java inheritance from ActionBarActivity to Activity and leave the dialog theme in the manifest as it is.

原因就是定义的Activity继承的是AppCompatActivity;而它需要使用相对应的style，不能使用其他Activity对应的style。一个简单的解决办法就是继承最基本的Activity。

 

参考链接：

http://stackoverflow.com/questions/21814825/you-need-to-use-a-theme-appcompat-theme-or-descendant-with-this-activity