我的配置文件是这样的：

<activity
            android:name="com.gemptc.pmp.first.activity.FirstActivity"
            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="com.gemptc.pmp.mypmp.activity.MypmpActivity" ></activity>
         <activity android:name="com.gemptc.pmp.mypmp.activity.About"></activity>
        <activity android:name="com.gemptc.pmp.mypmp.activity.FeedBack"></activity>
        <activity android:name="com.gemptc.pmp.main.activity.LoginActivity" android:label="loginActivity"></activity>
    </application>

运行到红色部分为什么只显示标题没显示内容呢？