title: android studio my helloWorld project has stopped
body: <p>I just instilled Android Studio and when I run the sample project hello world in the emulator it gives me  my project has stopped and it doesn't work </p>
  
  <p>myActivity.java </p>
  
  <pre><code>    package b3du.im.myapplication;
  
  import android.support.v7.app.ActionBarActivity;
  import android.os.Bundle;
  
  
  public class MyActivity extends ActionBarActivity {
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_my);
  
      }
  }
  </code></pre>
  
  <p>activity_my.xml</p>
  
  <pre><code>&lt;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"
      android:paddingLeft="@dimen/activity_horizontal_margin"
      android:paddingRight="@dimen/activity_horizontal_margin"
      android:paddingTop="@dimen/activity_vertical_margin"
      android:paddingBottom="@dimen/activity_vertical_margin"
      tools:context=".MyActivity"&gt;
  
      &lt;TextView
          android:text="@string/hello_world"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content" /&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>AndroidManifest.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="b3du.im.myapplication" &gt;
  
      &lt;application
          android:icon="@drawable/ic_launcher"
          android:label="@string/app_name"
          android:theme="@style/AppTheme" &gt;
          &lt;activity
              android:name=".MyActivity"
              android:label="@string/app_name" &gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
  
                  &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
      &lt;/application&gt;
  
  &lt;/manifest&gt;
  </code></pre>
  
  <p>logcat error</p>
  
  <pre><code>08-01 05:13:56.557    1884-1884/b3du.im.myapplication I/Process﹕ Sending signal. PID: 1884 SIG: 9
  08-01 05:21:26.244    1944-1944/b3du.im.myapplication D/AndroidRuntime﹕ Shutting down VM
  08-01 05:21:26.244    1944-1944/b3du.im.myapplication W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb2cc9b20)
  08-01 05:21:26.284    1944-1944/b3du.im.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: main
      Process: b3du.im.myapplication, PID: 1944
      java.lang.RuntimeException: Unable to start activity ComponentInfo{b3du.im.myapplication/b3du.im.myapplication.MyActivity}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
              at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
              at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
              at android.app.ActivityThread.access$800(ActivityThread.java:135)
              at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
              at android.os.Handler.dispatchMessage(Handler.java:102)
              at android.os.Looper.loop(Looper.java:136)
              at android.app.ActivityThread.main(ActivityThread.java:5017)
              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:779)
              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
              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.ActionBarActivityDelegate.onCreate(ActionBarActivityDelegate.java:108)
              at android.support.v7.app.ActionBarActivityDelegateICS.onCreate(ActionBarActivityDelegateICS.java:57)
              at android.support.v7.app.ActionBarActivity.onCreate(ActionBarActivity.java:98)
              at b3du.im.myapplication.MyActivity.onCreate(MyActivity.java:11)
              at android.app.Activity.performCreate(Activity.java:5231)
              at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
              at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
              at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
              at android.app.ActivityThread.access$800(ActivityThread.java:135)
              at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
              at android.os.Handler.dispatchMessage(Handler.java:102)
              at android.os.Looper.loop(Looper.java:136)
              at android.app.ActivityThread.main(ActivityThread.java:5017)
              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:779)
              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
              at dalvik.system.NativeStart.main(Native Method)
  </code></pre>