Basically I'm trying to build a game to learn flutter more.
Right now I'm just trying to get a Text widget to move from the top of the phone screen, towards the bottom of the phone screen... I'm building a Space Invaders type of game with just Text.
From what I've read by googling the problem, should I use Flame? Or can everything be done by just using the base Flutter framework (collision detection, moving widgets, etc...)? Thanks.
You can use Draggable class for dragging the item.
A simple way to solve this problem is to have the moving Text widget a child of the Stack() widget. Actually, the child of the Stack() widget is a Positioned() widget, which has left and top properties, which you can update periodically with a Timer.periodic function to move the widget down by incrementing top property. So, your Text widget is a child of the Positioned() widget, that you use for, well, positioning.
I have a working example of this in my slowly_moving_widgets_field project, where I have a bunch of arbitrary widgets moving about the screen every X seconds as you desire.
Related
Can Flutter Flame render Widget inside game world like other components? (not overlay widget).
(I want to apply forge2d physic to widget and I'm trying to do it with Flame.)
You can not, you can only do it through the overlay system or use a Stack, but the widgets are never "in" the game, but on top of the game.
The game can only have Flame Components added directly to it.
You can still interact with the overlay widgets from the game though, like this for example: https://twitter.com/spydon/status/1417832832693673988
In that example I simply wrap the ElevatedButton with Positioned and Transform and then I updated those with the values from corresponding BodyComponents.
At first — I have a widget, it contains and plays a specific animation which state cannot be saved or interrupted because animation data comes from a web server permanently and this stream is important.
Second — I have a ListView.builder with 'infinite' list of Cards (simple cards, doesn't important in this situation, app's screen contains 5 of them at the same time).
The problem is: is it possible to set given animated widget on every 10-th position of the ListView using the same instance of it in order to save it's animation state and not recreate animated widget every time? It must be the same widget, the animation must continue — one widget's instance on the screen at the time.
I tried to use a Stack with the animated widget wrapped with Offstage widget on the upper layer and the ListView with 'gaps' on every 10-th position. So Animated widget lives permanently and when it goes out of the screen I 'turn it off' with Offstage. And when it should appear on scroll I 'switch it on' with Offstage. But it is very difficult to position animated widget and synchronize its position with a scroll position of the ListView. For this purpose I use a GlobalKey for every 'gap' in the ListView, define it's Render Rectangle to position my Animated widget on/in the given gap.
Any ideas to solve this task more elegant? Maybe it is possible to make some 'deep copy' or 'singleton' or keep it alive (somehow) in the ListView or use some slivers, and reuse the same instance of it again and again when it appears?
I'm creating a scroll view that pads that center item with some extra space vertically. I want to accomplish two things:
1- Shrink the center item's padding at the same rate the user is moving his finger. For example, if the padding of the center item is 50 pixels and the user moved his finger for 10 pixels then I would like to decrement the padding to 40.
2- I would like to stop the list view from actually scrolling until the padding for the center item is 0. The list view should scroll as normal once the center item's padding is 0.
I'm a little lost here. I've been trying playing around with implementing my own ScrollController and ScrollPhysics but I haven't been able to achieve exactly what I'm looking for. I also saw that there was a class in Flutter called ScrollPosition that controls the position for each scrolling widget but I haven't been able to figure out how to use these to accomplish the behavior I'm looking for.
Could someone point me in the right direction?
Change the physics property of the ListView, NeverScrollablePhysics() doesn't allow scrolling.
Maybe use a GestureDetector for detecting the swipes.
Be careful of the placement of this widget though.
It can interfere with the normal scrolling of the listView.
Try experimenting with the animationController instead of calling setState() multiple times,
it's wasteful to refresh the screen multiple times just to change the padding.
When you swipe vertically, image is dragged towards the swipe, with fading out animation of black background.
And after release, it smoothly returns to it's previous position on the screen, like Hero animation does.
How is it possible to recreate such an effect using Flutter? The same scenario, in fullscreen photo view.
photo_view package is desired for fullscreen, so it shouldn't interfere with zooming.
What you need is actually an out-of-the-box widget, and it's surprisingly easy to use. It's called Hero. Basically, you wrap the widget you want to animate like that in a Hero widget, with a specific tag string, and, when you navigate to another screen, you wrap the destination widget in another Hero with the same tag. An effect like the one you shared can be achieved by wrapping two widgets with the same photo with Heroes in different PageRoutes.
Check out this Flutter widget of the week video to get you started, and this Flutter.dev article for a more detailed explanation on Hero widgets.
Edit: I see you are looking for a more specific image-viewer behavior. Then, I suggest you use the photo_view package, which includes many functionalities to visualize images, including the hero transition with swipe-dow-to-dismiss behaviors, pinching to zoom, etc.
I found the solution.
To create such an animation, you should use extended_image package, which has SlideOutPage widget for creation of such transitions.
I have been searching around for days in the jungle of widgets, trying to figure out which widget suits my purpose best.
What I have done so far: I have a Positioned widget with a listener, that I can drag around in a Stack with onPointerMove.
What I want to achieve is the following:
If I move my finger a bit faster and at some point let go, I would like to have the widget to continue with the given speed (with some friction) and direction (x,y) until it reaches some point.
Im a iOS developer and did this in Swift, but have I reached a point where I met the limit of Flutter?
Flutter has a Draggable widget which contains velocity in the onDragEnd event. You might use this and some basic animation to fling the widget using physics. Check out the Cookbook on the Flutter API site.