问错误类型3-活动类不存在

EN

<?xml version="1.0" encoding="utf-8"?>

<!-- WebRTC Dependencies -->
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />
<uses-feature
    android:glEsVersion="0x00020000"
    android:required="true" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />

<!-- PubNub Dependencies -->
<!--<uses-permission android:name="android.permission.INTERNET" />-->
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
<permission android:name="your.package.name.permission.C2D_MESSAGE" android:protectionLevel="signature" />
<uses-permission android:name="your.package.name.permission.C2D_MESSAGE" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_pubrtc"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="com.onlinevoicecallapp.MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name="com.onlinevoicecallapp.VideoChatActivity"
        android:label="@string/title_activity_video_chat"
        android:parentActivityName="com.onlinevoicecallapp.MainActivity"
        android:windowSoftInputMode="stateHidden"
        android:theme="@android:style/Theme.NoTitleBar.Fullscreen" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.onlinevoicecallapp.MainActivity" />
    </activity>
    <activity
        android:name="com.onlinevoicecallapp.IncomingCallActivity"
        android:label="@string/title_activity_incoming_call">
    </activity>
    <activity
        android:name="com.onlinevoicecallapp.LoginActivity"
        android:label="@string/title_activity_login" >
    </activity>
</application>