Android 启动出现白屏或者黑屏的问题

<style name="WelcomeAppTheme" parent="android:Theme.Light">
        <item name="android:windowBackground">@drawable/welcome</item>
        <item name="android:windowNoTitle">true</item>
    </style>

android:theme="@style/WelcomeAppTheme"

<activity
android:name="com.cloudroom.ufu.ui.UFuWelcomeActivity"
android:configChanges="orientation"
android:label="@string/app_name"
android:theme="@style/WelcomeAppTheme" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>