Android 系列 4.7發送/接收廣播消息

4.7發送/接收廣播消息

問題

您想創建一個接收另一個活動發送的簡單廣播消息的活動。

解

設置廣播接收器，實例化消息接收器對象，並創建IntentFilter。 然後向接收者注冊必須接收廣播消息的活動。

討論

示例4-12中的代碼設置廣播接收器，實例化消息接收器對象，並創建IntentFilter。

實例4-12。 創建和注冊BroadcastReceiver

// Instantiate message receiver object. You should
// create this class by extending android.content.BroadcastReceiver
// The method onReceive() of this class will be called when broadcast is sent
MyBroadcastMessageReceiver _bcReceiver = new MyBroadcastMessageReceiver();
// Create IntentFilter
IntentFilter filter = new IntentFilter(
MyBroadcastMessageReceiver.class.getName());
// And register your receiver with your activity which must receive broadcast message
// Now whenever this type of message is generated somewhere in the system -
// _bcReceiver.onReceive() method will be called within main thread of myActivity
myActivity.registerReceiver(_bcReceiver, filter);

實例4-13。 發布廣播事件

Intent intent = new Intent(
MyBroadcastMessageReceiver.class.getName());
intent.putExtra("some additional data", choice);
someActivity.sendBroadcast(intent);