adnroid 启动是没有标题栏

<activity
            android:name=".MainActivity"
            android:theme="@android:style/Theme.Light.NoTitleBar.Fullscreen"
            android:label="@string/app_name"
            android:screenOrientation="portrait" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".Index"
            android:screenOrientation="portrait"
            android:windowSoftInputMode="adjustPan" >
        </activity>