Android - java.lang.SecurityException: 权限拒绝：启动Intent

我在项目的构建路径上有一个库（jar）文件。该项目通过以下意图访问该库中的MainActivity：

final Intent it = new Intent();
it.setClassName("com.example.lib", "com.example.lib.MainActivity");
startActivity(it);

它曾经能够工作一段时间，但突然出现了“ActivityNotFoundException：没有找到处理Intent的活动”，我解决了这个问题。但现在我卡在了“java.lang.SecurityException：Permission Denial：starting Intent”上。

我尝试了stackoverflow上提出的所有建议（检查清单文件中的重复项；将android:exported =“true”添加到库清单中；Eclipse>项目>清理；添加/修改“intent-filter”标记等），甚至尝试重写项目的清单，但没有任何进展。

以下是logcat输出：

11-07 06:20:52.176: E/AndroidRuntime(4626): FATAL EXCEPTION: main
11-07 06:20:52.176: E/AndroidRuntime(4626): java.lang.SecurityException: Permission     Denial: starting Intent { cmp=com.example.lib/.MainActivity } from ProcessRecord{40dd3778     4626:com.example.project/u0a10046} (pid=4626, uid=10046) not exported from uid 10047
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.os.Parcel.readException(Parcel.java:1425)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.os.Parcel.readException(Parcel.java:1379)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.app.ActivityManagerProxy.startActivity(ActivityManagerNative.java:1885)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.app.Instrumentation.execStartActivity(Instrumentation.java:1412)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.app.Activity.startActivityForResult(Activity.java:3370)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.app.Activity.startActivityForResult(Activity.java:3331)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:824)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.app.Activity.startActivity(Activity.java:3566)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.app.Activity.startActivity(Activity.java:3534)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at com.example.project.MainActivity.onOptionsItemSelected(MainActivity.java:93)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.app.Activity.onMenuItemSelected(Activity.java:2548)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:366)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:980)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at com.android.internal.view.menu.ActionMenuView.invokeItem(ActionMenuView.java:547)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at com.android.internal.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:115)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.view.View.performClick(View.java:4204)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.view.View$PerformClick.run(View.java:17355)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.os.Handler.handleCallback(Handler.java:725)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.os.Handler.dispatchMessage(Handler.java:92)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.os.Looper.loop(Looper.java:137)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at android.app.ActivityThread.main(ActivityThread.java:5041)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at java.lang.reflect.Method.invokeNative(Native Method)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at java.lang.reflect.Method.invoke(Method.java:511)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
11-07 06:20:52.176: E/AndroidRuntime(4626):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
11-07 06:20:52.176: E/AndroidRuntime(4626):     at dalvik.system.NativeStart.main(Native Method)

项目的清单XML：

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.project"
android:versionCode="4"
android:versionName="4.0" >

<!-- Permissions -->
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<supports-screens android:anyDensity="true" />

<!-- SDK Settings -->
<uses-sdk
    android:minSdkVersion="11"
    android:targetSdkVersion="18" />

<!-- APP Start -->
<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >

<!-- App Activity -->
    <activity
        android:name="com.example.project.MainActivity"
        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>

<!-- Library Activity -->
    <activity android:name="com.example.lib.MainActivity" android:label="LibMain">
         <intent-filter>
        <action android:name="android.intent.action.MAIN"></action>
     </intent-filter>
    </activity>

</application>
<!-- END - APP -->

</manifest>

我忽略了什么？有什么建议吗？

编辑

我已经更新了manifest.xml，包括所有其他活动，并且以某种方式解决了问题。意图活动启动时没有任何错误。但是，这只在AVD上有效。在实际设备上仍会出现相同的错误。我已经完全卸载并重新安装了设备上的应用程序，但仍然出现相同的错误。