1、PendingIntent作用
根据字面意思就知道是延迟的intent,主要用来在某个事件完成后执行特定的Action。PendingIntent包含了Intent及Context,所以就算Intent所属程序结束,PendingIntent依然有效,可以在其他程序中使用。
常用在通知栏及短信发送系统中。
PendingIntent一般作为参数传给某个实例,在该实例完成某个操作后自动执行PendingIntent上的Action,也可以通过PendingIntent的send函数手动执行,并可以在send函数中设置OnFinished表示send成功后执行的动作。
2、PendingIntent举例
a. 系统通知栏
NotificationManager nm = (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE); int icon = android.R.drawable.stat_notify_chat; long when = System.currentTimeMillis() + 2000; Notification n = new Notification(icon, "通知栏demo提醒", when); n.defaults = Notification.DEFAULT_SOUND; n.flags |= Notification.FLAG_AUTO_CANCEL; Intent openintent = new Intent(this, DemoList.class); PendingIntent pi = PendingIntent.getActivity(this, 0, openintent, PendingIntent.FLAG_CANCEL_CURRENT); n.setLatestEventInfo(this, "通知栏demo提醒title", "通知栏demo提醒text", pi); nm.notify(0, n);
setLatestEventInfo表示设置点击该通知的事件
b. 短信系统举例
private final static String SEND_ACTION = "send"; private final static String DELIVERED_ACTION = "delivered"; private void sendSms(String receiver, String text) { SmsManager s = SmsManager.getDefault(); PendingIntent sentPI = PendingIntent.getBroadcast(this, 0, new Intent(SEND_ACTION), PendingIntent.FLAG_CANCEL_CURRENT); PendingIntent deliveredPI = PendingIntent.getBroadcast(this, 0, new Intent(DELIVERED_ACTION), PendingIntent.FLAG_CANCEL_CURRENT); // 发送完成 registerReceiver(new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { switch (getResultCode()) { case Activity.RESULT_OK: Toast.makeText(getBaseContext(), "Send Success!", Toast.LENGTH_SHORT).show(); break; case SmsManager.RESULT_ERROR_GENERIC_FAILURE: Toast.makeText(getBaseContext(), "Send Failed because generic failure cause.", Toast.LENGTH_SHORT).show(); break; case SmsManager.RESULT_ERROR_NO_SERVICE: Toast.makeText(getBaseContext(), "Send Failed because service is currently unavailable.", Toast.LENGTH_SHORT).show(); break; case SmsManager.RESULT_ERROR_NULL_PDU: Toast.makeText(getBaseContext(), "Send Failed because no pdu provided.", Toast.LENGTH_SHORT).show(); break; case SmsManager.RESULT_ERROR_RADIO_OFF: Toast.makeText(getBaseContext(), "Send Failed because radio was explicitly turned off.", Toast.LENGTH_SHORT).show(); break; default: Toast.makeText(getBaseContext(), "Send Failed.", Toast.LENGTH_SHORT).show(); break; } } }, new IntentFilter(SEND_ACTION)); // 对方接受完成 registerReceiver(new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { switch (getResultCode()) { case Activity.RESULT_OK: Toast.makeText(getBaseContext(), "Delivered Success!", Toast.LENGTH_SHORT).show(); break; default: Toast.makeText(getBaseContext(), "Delivered Failed!", Toast.LENGTH_SHORT).show(); break; } } }, new IntentFilter(DELIVERED_ACTION)); // 发送短信,sentPI和deliveredPI将分别在短信发送成功和对方接受成功时被广播 s.sendTextMessage(receiver, null, text, sentPI, deliveredPI); }
以上的两个PendingIntent sentPI和deliveredPI将分别在短信发送成功和对方接受成功时被广播
3、Intent和PendingIntent的区别
a. Intent是立即使用的,而PendingIntent可以等到事件发生后触发,PendingIntent可以cancel
b. Intent在程序结束后即终止,而PendingIntent在程序结束后依然有效
c. PendingIntent自带Context,而Intent需要在某个Context内运行
d. Intent在原task中运行,PendingIntent在新的task中运行