PendingIntent详解.doc

PendingIntent详解一. 基本用法public final class PendingIntent extends Objectimplements Parcelable PendingIntent是一个特殊的Intent, 是对Intent的包装,它持有context和intent.可以理解为一个延时执行的Intent.它只有在满足特定条件才会执行. 主要的使用的地方和例子：通知Notificatio的发送，短消息SmsManager的发送和警报器AlarmManager的执行等等。PendingIntent就是一个可以在满足一定条件下执行的Intent，它相比于Intent的优势在于自己携带有Context对象，这样他就不必依赖于某个activity才可以存在。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。PendingIntent用于描述Intent及其最终的行为. 你可以通过getActivity(Context context, int requestCode, Intent intent, int flags)系列方法从系统取得一个用于启动一个Activity的PendingIntent对象, 可以通过getService(Context context, int requestCode, Intent intent, int flags)方法从系统取得一个用于启动一个Service的PendingIntent对象 可以通过getBroadcast(Context context, int requestCode, Intent intent, int flags)方法从系统取得一个用于向BroadcastReceiver的Intent广播的PendingIntent对象cancel()函数public voidcancel()Since:API Level 1Cancel a currently active PendingIntent. Only the original application owning an PendingIntent can cancel it.只有PengdingIntent的原应用程序才能调用cancel()来把它从系统中移除掉。 返回的PendingIntent可以递交给别的应用程序，然后继续处理。这里的话你可以稍后才处理PendingIntent中描述的Intent及其最终行为。注意：两个PendingIntent对等是指它们的operation一样, 且其它们的Intent的action, data, categories,components和flags都一样。但是它们的Intent的Extra可以不一样。主要常量l FLAG_CANCEL_CURRENT:如果当前系统中已经存在一个相同的PendingIntent对象，那么就将先将已有的PendingIntent取消，然后重新生成一个PendingIntent对象。l FLAG_NO_CREATE:如果当前系统中不存在相同的PendingIntent对象，系统将不会创建该PendingIntent对象而是直接返回null。l FLAG_ONE_SHOT:该PendingIntent只作用一次。在该PendingIntent对象通过send()方法触发过后，PendingIntent将自动调用cancel()进行销毁，那么如果你再调用send()方法的话，系统将会返回一个SendIntentException。l FLAG_UPDATE_CURRENT:如果系统中有一个和你描述的PendingIntent对等的PendingInent，那么系统将使用该PendingIntent对象，但是会使用新的Intent来更新之前PendingIntent中的Intent对象数据，例如更新Intent中的Extras。二. Intent和PendingIntent的区别l Intent是立即使用的，而PendingIntent可以等到事件发生后触发，PendingIntent可以cancell Intent在程序结束后即终止，而PendingIntent在程序结束后依然有效l PendingIntent自带Context，而Intent需要在某个Context内运行l Intent在原task中运行，PendingIntent在新的task中运行三 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);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