broadcast的intent不能启动一个activity

Note that, although the Intent class is used for sending and receiving
these broadcasts, the Intent broadcast mechanism here is completely separate
from Intents that are used to start Activities with

Context.startActivity()

.
There is no way for a BroadcastReceiver
to see or capture Intents used with startActivity(); likewise, when
you broadcast an Intent, you will never find or start an Activity.
These two operations are semantically very different: starting an
Activity with an Intent is a foreground operation that modifies what the
user is currently interacting with; broadcasting an Intent is a background
operation that the user is not normally aware of.