如何从通知活动返回到主活动？

// 在通知活动中创建返回主活动的意图
Intent intent = new Intent(this, MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

// 创建返回主活动的PendingIntent
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_ONE_SHOT);

// 创建通知
NotificationCompat.Builder builder = new NotificationCompat.Builder(this)
        .setSmallIcon(R.drawable.notification_icon)
        .setContentTitle("通知标题")
        .setContentText("通知内容")
        .setContentIntent(pendingIntent)
        .setAutoCancel(true);

// 显示通知
NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(0, builder.build());