title: cannot be cast to android.app.Activity
body: <p>please help when i run my application i get these errors, im trying to make an android game</p>
  
  <p>i have been trying to solve this problem and other problems for more than 3 days  </p>
  
  <pre><code>&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.zargoun.please"
      android:versionCode="1"
      android:versionName="1.0" &gt;
  
      &lt;uses-sdk
          android:minSdkVersion="8"
          android:targetSdkVersion="17" /&gt;
  
      &lt;uses-permission android:name="android.permission.INTERNET"/&gt;
  
      &lt;application
          android:allowBackup="true"
          android:icon="@drawable/ic_launcher"
          android:label="@string/app_name"
          android:theme="@style/AppTheme" &gt;
          &lt;activity
              android:name="com.zargoun.please.Main"
              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>StackTrace    </p>
  
  <pre><code>     D/AndroidRuntime(1115): Shutting down VM
       W/dalvikvm(1115): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
       E/AndroidRuntime(1115): FATAL EXCEPTION: main
       E/AndroidRuntime(1115): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.zargoun.please/com.zargoun.please.Main}: java.lang.ClassCastException: com.zargoun.please.Main cannot be cast to android.app.Activity
       E/AndroidRuntime(1115):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
       E/AndroidRuntime(1115):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
       E/AndroidRuntime(1115):    at android.app.ActivityThread.access$600(ActivityThread.java:141)
       E/AndroidRuntime(1115):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
       E/AndroidRuntime(1115):    at android.os.Handler.dispatchMessage(Handler.java:99)
       E/AndroidRuntime(1115):    at android.os.Looper.loop(Looper.java:137)
       E/AndroidRuntime(1115):    at android.app.ActivityThread.main(ActivityThread.java:5041)
       E/AndroidRuntime(1115):    at java.lang.reflect.Method.invokeNative(Native Method)
       E/AndroidRuntime(1115):    at java.lang.reflect.Method.invoke(Method.java:511)
       E/AndroidRuntime(1115):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
       E/AndroidRuntime(1115):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
       E/AndroidRuntime(1115):    at dalvik.system.NativeStart.main(Native Method)
       E/AndroidRuntime(1115): Caused by: java.lang.ClassCastException: com.zargoun.please.Main cannot be cast to android.app.Activity
       E/AndroidRuntime(1115):    at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
       E/AndroidRuntime(1115):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
       E/AndroidRuntime(1115):    ... 11 more
  </code></pre>
  
  <p>i get Error: The method setContentView(int) in the type Activity is not applicable for the arguments (Maing)</p>
  
  <pre><code>public class Main extends Activity {
  
      private Maing _game;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          // TODO Auto-generated method stub
          super.onCreate(savedInstanceState);
          _game = new Maing();
  
          setContentView(_game);
      }
  
  
  }
  </code></pre>
  
  <p>this is the class maing.java it implements Screen from libgdx library </p>
  
  <pre><code>import com.badlogic.gdx.Screen;
  
  public class Maing implements Screen{
  
      @Override
      public void dispose() {
          // TODO Auto-generated method stub
  
      }
  
      @Override
      public void hide() {
          // TODO Auto-generated method stub
  
      }
  
      @Override
      public void pause() {
          // TODO Auto-generated method stub
  
      }
  
      @Override
      public void render(float arg0) {
          // TODO Auto-generated method stub
  
      }
  
      @Override
      public void resize(int arg0, int arg1) {
          // TODO Auto-generated method stub
  
      }
  
      @Override
      public void resume() {
          // TODO Auto-generated method stub
  
      }
  
      @Override
      public void show() {
          // TODO Auto-generated method stub
  
      }
  </code></pre>