not screen horizontal android exam

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      android:versionCode="1"
      android:versionName="1.0" package="softech.mobile">
    <uses-sdk android:minSdkVersion="8" />
 <uses-permission android:name="android.permission.INTERNET" />
    <application android:icon="@drawable/icon" 
     android:label="@string/app_name" 
     android:theme="@android:style/Theme.NoTitleBar">
        <activity android:name="softech.mobile.activity.AiLaTrieuPhuActivity"
                  android:label="@string/app_name"
                  android:configChanges="orientation|keyboardHidden"
         android:screenOrientation="portrait"
                  >            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>
</manifest>