如果已收到来自服务的消息，则通知活动

Question

Hello Please i need help,

How Can I notify my activity if a message has been received from a GCMListener service ruuning in background.

Answer 1

First, bear in mind that you may not have an activity around. Android may have terminated your process (eg, user pressed HOME and time elapsed), and your newly-created process may just have your GCM-handling service.

That being said, you can use an event bus:

• LocalBroadcastManager
• greenrobot's EventBus
• Square's Otto
• etc.

Have the service post an event on the bus. Have your activity set up to receive the event. If the service posts the event, and the event is unhandled, the service knows that the UI is not around and can perhaps do something else with the message (eg, raise a Notification , save the message in a database for later use).