要在Android Studio中发送通知，可以使用NotificationCompat.Builder类来构建通知。以下是一个简单的示例代码：

// 创建通知渠道（仅适用于Android 8.0及更高版本）
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    CharSequence name = "Channel Name";
    String description = "Channel Description";
    int importance = NotificationManager.IMPORTANCE_DEFAULT;
    NotificationChannel channel = new NotificationChannel("channel_id", name, importance);
    channel.setDescription(description);
    // 注册通知渠道
    NotificationManager notificationManager = getSystemService(NotificationManager.class);
    notificationManager.createNotificationChannel(channel);
}

// 创建通知
NotificationCompat.Builder builder = new NotificationCompat.Builder(this, "channel_id")
        .setSmallIcon(R.drawable.ic_notification)
        .setContentTitle("Notification Title")
        .setContentText("Notification Content")
        .setPriority(NotificationCompat.PRIORITY_DEFAULT);

// 点击通知时打开的Activity
Intent intent = new Intent(this, MainActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
builder.setContentIntent(pendingIntent);

// 发送通知
NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);
notificationManager.notify(1, builder.build());

请确保在AndroidManifest.xml中的标签中添加以下权限：

另外，请注意在Android 8.0及更高版本中，需要创建并注册通知渠道，以便正确显示通知。