Hello I have a ListView with different Widgets of different height. Now I want to know which of those Widgets are at the moment visible in the ListView. Does anyone has an idea how to do it. I can't use to scroll_to_widget package because it interferes other implementations.
Try using https://pub.dev/packages/visibility_detector maybe you can create a separate list and store true according to index, based on their visibility?
Related
I want to create this type of listview using flutter.
https://dribbble.com/shots/6872462-Food-ordering-app-Animate
You can find out more by clicking on this link. But I don't know how to create this type of list. I mean, you can see in the GIF that the list is indexed based.
A fixed indexed item container is colored.
How can I achieve it?
Flutter provides you with a widget very similar to the result you want to achieve called NavigationRail.
You will not have the animation by default, but you can maybe search in the source code of this widget how to create a custom widget that will implement animations.
Consider the case that I have 3 adjacent list view with each list view having a sized widget of some height. Each list view has around 24 child items. I'm trying to scale the widget using onScaleUpdate in GestureDetector.
onScaleUpdate I want to change the height of each child item of all the 3 listviews.
Is rebuilding all child better or should I rebuild the whole widget?
As #Yeasin Sheikh pointed out, using ListView.builder is good because it builds only the needed children (the ones inside the screen and just a few ones outside as precaution). And as to actually answering your question, I'm no Flutter expert, but using ListView.builder I don't think it makes that much difference, Flutter is intelligent enough to solve this by itself.
I can also create lists by this code that I can with ListView.builder so what differentiate both?
for(Item in List) View(Item);
I am new to development and trying to understand this.
Is it good if I use above approach?
When items are limited(not more but few) you can use ListView widget, but for many items (like as thousands of items, also created on demand) - You should use ListView.builder.
The difference between of them is: When you use ListView, all the items are rendered on screen. But when you use ListView.builder, items are rendered on demand. Only the items are visible on the screen and few of above & bottom are rendered.
For more:
ListView
ListView.builder
So I am not looking for filters but I am looking for scroll widget. I have tried generating listview items abd getting position of listview to give items ratio but I wasn't able to get any functionality while in certain index position. Any help would be helpfull. Naming of the widget or special widgets that can make me do this etc.
You can use ListView or ListView.builder to do that, but with circle-shaped widgets as the children.
You can check out this tutorial to do the horizontal list. And you can check out this StackOverflow question, to create a circle button. Or instead of a button, you want to use the CircleAvatar (to add an image in it), you can check out this official doc.
I use GridView in my Flutter's app. Size my GridView is 30x4(with different widgets).
I need to update one widget in my gridView. I have two solutions and I need to choose the best.
Update all GridView. It is easy but I think this is not optimal (rebuild the entire grid for one change).
Update one widget. it is more complicated. but I know how to do it. This is a similar example.
what do you advise?