PendingIntent android.app.PendingIntent.getActivity(Context context, int requestCode, Intent intent, int flags)
public static PendingIntent getActivity (Context context, int requestCode, Intent intent, int flags)
Since: API Level 1
Retrieve a PendingIntent that will start a new activity, like calling Context.startActivity(Intent). Note that the activity will be started outside of the context of an existing activity, so you must use the Intent.FLAG_ACTIVITY_NEW_TASK launch flag in the
Intent.
找到一个PendingIntent用来开始启动一个新的activity，类似于调用Context.startActivity(Intent)，注意这个Activity将在当前存在的Activity外部启动，你必须使用Intent中的Intent.FLAG_ACTIVITY_NEW_TASK标志登陆这个Acitivity.
Parameters
context The Context in which this PendingIntent should start the activity.
requestCode Private request code for the sender (currently not used).
intent Intent of the activity to be launched.
flags May be FLAG_ONE_SHOT, FLAG_NO_CREATE, FLAG_CANCEL_CURRENT, FLAG_UPDATE_CURRENT, or any of the flags as supported by Intent.fillIn() to control which unspecified parts of the intent that can be supplied when the actual send happens.
Returns
Returns an existing or new PendingIntent matching the given parameters. May return null only if FLAG_NO_CREATE has been supplied.
例如：
PendingIntent contentIntent = PendingIntent.getActivity(this, 0,
new Intent(this, NotifyingController.class), 0);
// Set the info for the views that show in the notification panel.
notification.setLatestEventInfo(this, getText(R.string.status_bar_notifications_mood_title),
text, contentIntent);