I have made a LazyRow that i now want to be able to get the scrollposition from. What i understand Scrollablerow has been deprecated. (correct me if im wrong) The thing is that i cant make a scrollablerow so i thought lets make a lazy one then. but i have no clue how to get scrollposition from the lazyrow. i know how to get index but not position if that eaven exists. here is what i have tried.
val scrollState = rememberScrollState()
LazyRow(scrollState = scrollstate){
}
For LazyScrollers, there are separate LazyStates.
I think there's just one, in fact, i.e. rememberLazyListState()
Pass that as the scroll state to the row and then you can access all kinds of info. For example, you could get the index of the first visible item, as well as its offset. There are direct properties for this stuff in the object returned by the above initialisation. You can also perform some more complex operations using the lazyListState.layoutInfo property that you get.
Also, ScrollableRow may be deprecated as a #Composable, but it is just refactored, a bit. Now, you can use the horozontalScroll() and verticalScroll() Modifiers, both of which accept a scrollState parameter, which expects the same object as the one you've created in the question.
Usually, you'd use LazyScrollers since they're not tough to implement and also are super-performant, but the general idea is that they are used with large datasets whereas non-lazy scrollers are okay for small sized lists and stuff. This is because the lazy ones cache only a small fraction of the entire list, making your UI peformant, which is not something regular scrollers do, and not a problem for small datasets.
They're like equivalents of RecyclerView from the View System
Related
I build program, when in one part I have some ranking, and I would like to give users option to customize it.
In my code I have a function that gets objects and returnes them packed with points and position in ranking (for now it calculates the arithmetic mean of some object's values).
My question is is it possible to give e.g. admin chance to write this function via admin panel and use it, so if he would like to one day use harmonic mean he could without changing source code?
Yes, you could just store a string in the database and exec() it with suitable arguments...
However, you'll have to be careful – Python code can practically never be sandboxed perfectly. In the event that you accept any arbitrary Python code for this, and someone with nefarious intents gets to your admin panel to change the expression, they can do practically anything.
In other words, don't use raw Python for the code you store.
In my current model I have 2 entities: Student and StudentOrdersHistory. We're using a history table to record all the orders from the student.
However, we particularly need to work with the latest order history. At first, I used some circular reference like the following:
StudentOrderHistory.student_id --> Student
Student.latest_order --> StudentOrderHistory
The reason for this is that we expect the relation to have hundreds of rows (student here is just an example to make it simple to ask what I need), but since we mostly need to work with the last one, we figured it's pointless loading all of them and then doing some $student->orders->last(), since it'd have to load all the records.
Needless to say, this implementation brought a pain when deleting a Student, as the circular reference won't let me do it without first having to delete the Student.latest_order reference.
Is there anyway I can load into a Student property (like Student::$latestOrder) only the latests one using DQL?
Sure, but you might not be able to do it directly through the Student object. Sacrificing this convenience should get your the performance improvement you want, and in fact doctrine best practices suggest constraining relationships as much as possible.
I haven't tested this code, but you probably know how to get it working. I'd add a method to the OrderRepository, like
public function getLatestForStudent(Student $student)
{
$this->findOneBy(['student' => $student], ['created']);
}
I need a way for ember router to route to a recursive path.
For Example:
/:module
/:module/:submodule
/:module/:submodule/:submodule
/:module/:submodule/:submodule/...
Can this be done with Embers router, and if so, how?
I've been looking for examples, tearing apart the source, and I've pretty much come to the conclusion, it's not possible.
In a previous question, someone had pointed me to a way to get the url manually and split it, but I'm stuck at creating the state for the router to resolve to.
As of now, in my project, I currently just use the Ember.HashLocation to setup my own state manager.
The reason for the need of this, is because the module definitions are stored in a database, and at any given point a submodule of a submodule, recursively, could be added. So I'm trying to make the Application Engine handle the change.
Do your submodules in the database not have unique IDs? It seems to me that rather than representing your hierarchy in the path, you should just go straight to the appropriate module or submodule. Of course the hierarchy is still in your data model, but it shouldn't have to be represented in your routing scheme. Just use:
/module/:moduleId
/submodule/:submoduleId
And don't encode the hierarchy in the routes. I understand it might be natural to do so, but there's probably not a technical reason to.
If your submodules don't have unique ids, it's maybe a little tougher...you could build a unique ID by concatenating the ancestor ids together (say, with underscores), which is similar to splitting the URL, but a little cleaner probably. I will say that Ember/Ember Data doesn't seem to be too easy to use with entities with composite keys--if everything has a simple numeric key everything becomes easier (anyone want to argue with me on this, please explain to me how!).
DO you mean like this:
App.Router.map(function(match) {
match('/posts').to('blogPosts');
match('/posts/:blog_post_id').to('showBlogPost');
});
I'm using QSqlQuery::prepare() and ::addBindValue() for my queries in a Qt project I'm working on. There's a lot of repeated code and though I think that's the "right" way, I wanted to make sure. Perhaps someone has alternative ideas? Example:
QSqlQuery newQuery;
newQuery.prepare("INSERT INTO table "
"(foo,bar,baz,"
"herp,derp,biggerp,"
"alpha,beta,gamma,"
"etc) VALUES "
"(?,?,?,"
"?,?,?,"
"?,?,?,"
"?)");
newQuery.addBindValue(this->ui->txtFoo->text());
newQuery.addBindValue(this->ui->txtBar->text());
newQuery.addBindValue(this->ui->txtBaz->text());
newQuery.addBindValue(this->ui->txtHerp->text());
newQuery.addBindValue(this->ui->txtDerp->text());
newQuery.addBindValue(this->ui->txtBiggerp->text());
newQuery.addBindValue(this->ui->txtAlpha->text());
newQuery.addBindValue(this->ui->txtBeta->text());
newQuery.addBindValue(this->ui->txtGamma->itemText(0));
newQuery.addBindValue(this->ui->txtEtc->text());
newQuery.exec();
You can see there's a bunch of the same "newQuery.addBindValue(this->ui->__________" over and over. Is this the 'best' way to go about it?
Also, I asked in #qt on freenode the other night but didn't get a definitive answer; will the above (::prepare with ::addBindValue) protect agains SQL injection? The reference didn't really say.
It might look a bit tidier if you first create a QMap or QStringList with the bindings, then iterate through that data structure and call addBindValue() for each item in the list/map.
In relation to your sub-question on SQL injection, that combination of ::prepare and ::addBindValue does indeed fully protect against it. This is because the bound values are never parsed by the SQL engine; they're just values that slot in after compilation (the preparation step) and before execution.
Of course, you have to be careful when taking values out of the DB too, but that's not protecting the database but rather ensuring that the values aren't used to cause other mischief (e.g., injecting unexpected malicious <script> tags into HTML or, worse still, a <blink> or <marquee> monstrosity). But that's another problem, and doesn't apply to all uses anyway; putting the values in a strictly plain text GUI field is usually no problem.
I'm taking over a project and wanted to understand if this is common practice using SOAP. The process that is currently in place I have to query all the values before I do an update cause I need to pass back all the values that are not being updated. Does this sound right?
Example Values:
fname=phill
lname=pafford
address=123 main
phone:222-555-1212
So if I just wanted to update the phone number I need to query for the record, get all the values and submit these values for an update.
Example Update Values:
fname=phill
lname=pafford
address=123 main
phone:111-555-1212
I just want to know if this is common practice or should I change the functionality of this?
This is not specific to SOAP. It may simply be how the service is designed. In general, there will be fields that can only be updated if you have the original value: you can't add one to a field unless you know the original value, for instance. The service seems to have been designed for the general case.
I don't think that it is a very "common" practice. However I've seen cases where the old values are posted together with the new values, in order to validate that noone else has updated the values in the meantime.