Android Facebook Login "LoginActivity could not be started"

So I had the same issue and fixed it by... setting up my app properly on the Facebook developers page.

Basically my app was missing:

• (Google Play) package name
• class name
• a key hash

Once I fill these in, the error was gone.

I was able to solve this by removing LoginActivity from my AndroidManifest.xml

<!--Remove this-->
<activity android:name="com.facebook.LoginActivity" 
android:theme="@android:style/Theme.Translucent.NoTitleBar" 
android:label="@string/app_name" /> 

and adding

<!--Add this-->
<activity android:name="com.facebook.FacebookActivity"
 android:configChanges="keyboard|keyboardHidden|screenLayout|screenSize|orientation"
 android:theme="@android:style/Theme.Translucent.NoTitleBar" 
 android:label="@string/app_name" />