I am trying to add a collapsable note that expands to the full height determined by the amount of text inside of it with the click of a button.
The problem I am facing is when adding variable to determine the height of the AnimatedContainer
I want the AnimatedContainer to take a certain height if isCollapsed is true and a default height (that is, as much height as needed for the children (same as not specifying height)). I am trying to use condition ? do something : do something else but because it requires the :, I cannot just tell it to revert back to default.
This is simplified for the purpose of demonstration:
return AnimatedContainer(
duration: Duration(milliseconds: 300),
height: isCollapsed ? 100 : (revert to default),
child: Column(
TextField(),
TextField(),
),
)
Have you tried setting it to null?
height: isCollapsed ? 100 : null,
Related
I'm trying to create a expand-able container that have a specific height of 150 when it shrink and only show maximal 2 line of text.
But when the user click on the container it will expand to height of depending on the text if the text from the database is 10 line the height have to be 10 line but when the max text is 20 the height need to adjust to 20 line.
Can I achieve it using animatedContainer or animatedSize ?
Yes you can use an animated container..
bool widgetExpanded = false;
InkWell
(
onTap :(){
setState((){
widgetExpanded = !widgetExpanded;
});
}
child : AnimatedContainer(
height : widgetExpanded ? 300:150, //<-- optional. Only if you wish to add height
duration: Duration(milliseconds: 500),
child: Text("Some big text here", style: TextStyle(
maxLines: widgetExpanded? null: 2,
overflow: TextOverflow.ellipsis,
))
)
)
Also please take a look at expansion tile
https://api.flutter.dev/flutter/material/ExpansionTile-class.html
Use ExpansionTile to create that animation, it is expanded to your text or any widget as you like.
I have a column holding a number of containers. The top and bottom containers are always shown, but the ones between sit inside a Visibility widget. If the user taps the screen, the middle containers are made visible, and then are made invisible again on the next tap. So essentially, the column expands and contracts each time it's tapped.
I'd like the expansion and contraction to happen a bit more gracefully - currently it looks very harsh when the middle containers just suddenly appear. Is there any way of animating the way in which the containers are made visible and hidden? Or should I be looking at using a totally different Widget than Visibility?
You can use an animated crossfade. Make the first child as SizedBox.shrink() and second child as the widget that you wish to display and it should be animating as expected. And switch according to the requirement
bool _first = true;
AnimatedCrossFade(
duration: const Duration(seconds: 1),
firstChild: const SizedBox.shrink(),
secondChild: const FlutterLogo(style: FlutterLogoStyle.stacked, size: 100.0),
crossFadeState: _first ? CrossFadeState.showFirst : CrossFadeState.showSecond,
)
Alter the value of _first to true or false.
I have a layout where I have a row and inside this row, I have a custom expansion tiles list and a custom widget, which is a rectangle with a fixed width of 5 pixels, the height of the rectangle must be the same, as the expansion tile's height.
To make the rectangle the same height as the expansion panel, I used intrinsic height.
So, the structure is this IntrinsicHeight: Row: [ExpansionPanel, Container]
The problem is that when I use IntrinsicHeight all animations are broken.
Animation in the expansion tile list is working, but the container which contains the row does not resize following the animation, but does it without any intermediate steps.
I have tried to use different types of animation.
Implicit tween animation builder
return TweenAnimationBuilder(
tween: Tween<double>(begin: 0, end: opened ? 1 : 0),
duration: Duration(milliseconds: 600),
builder: (_,double value, __){
return ClipRect(
clipBehavior: Clip.antiAlias,
child: Align(
alignment: Alignment.bottomCenter,
heightFactor: value,
child: value != 0 ? body : null,
),);
}
);
Cross fade animation
return AnimatedCrossFade(
firstChild: body,
secondChild: Container(height: 0,),
duration: Duration(milliseconds: 600),
crossFadeState: opened ? CrossFadeState.showFirst : CrossFadeState.showSecond,
sizeCurve: Curves.ease,
);
Changing animation type didn't fix my problem.
My questions are following:
Is there an option to make an animation of size simultaneously using IntrinsicHeightWidget
If there is not such an option, Is there an option to make a Rectangle widget with the same height as an expansion tile list, but without the IntrinsicHeight widget.
I have captured a video to show how the problem looks like.
https://www.youtube.com/watch?v=xpQ8QHwHUWQ
I have seen similar problems, but I didn't get success implementing them in my case.
Flutter - Animate change on height when child of container renders
Stretch children of a Flutter Row to the maximum *natural* height
How to stretch Containers inside Row to maximum available height?
I'm building an expansible card in flutter, which I wanto to animate. I want the parent Container to have a limited height while the card is collapsed, and to have whatever height is necessary for the child when it's expanded. I can reach this result using maxHeight: double.infinity:
Container(
alignment: Alignment.topCenter,
clipBehavior: Clip.hardEdge,
constraints: isExpanded
? BoxConstraints(maxHeight: double.infinity)
: BoxConstraints(maxHeight: 76),
decoration: BoxDecoration(),
child: widget.child,
),
)
But whatever maxHeight value I use other than double.infinity causes the parent to have that exact height, instead of just having the height needed by the child. I can't use double.infinity because that's not animatable. I've tried following this answer's tips, but whatever I wrap the child with, the parent always grows. I've tried changing the child, but even if I use maxHeight on the child itself, the parent always grows to the defined maxHeight.
Why does this happen? Shouldn't maxHeight only cause the parent to expand if needed? How come it works correctly with double.infinity, but doesn't with anything else?
Also, I have tried reaching this result with AnimatedSize, it sort of works. When it is expanding, it works perfectly, but when the child is collapsing, it collapses instantly, and the AnimatedSize's animation follows after.
Edit:
I see what you mean, you want to use AnimatedContainer, but in order to be animated like you want it, it requires you to specify the height. double.infinity won't do in this case, the error message you're getting is correct.
There are ways to get widget height.. I suggest you check this answer: https://stackoverflow.com/a/49650741/7248289
Also, this one might help: https://stackoverflow.com/a/54173729/7248289
Is there any way to slowly fade-in and out a floating action button? I have in my list a FAB to offer the user a way to quickly scroll to the top of the list.
So far I've found in various posts how to detect when the list is scrolled to the top or away from the top (https://medium.com/#diegoveloper/flutter-lets-know-the-scrollcontroller-and-scrollnotification-652b2685a4ac), but I fail to find how I can change the alpha value of a widget. Any idea how to solve this?
Thanks
Martin
This example is from flutter dev page:
With a AnimatedOpacity you can fade any widget.
Just put you floating action button as child of AnimatedOpacity.
Here is some example:
AnimatedOpacity(
// If the widget is visible, animate to 0.0 (invisible).
// If the widget is hidden, animate to 1.0 (fully visible).
opacity: _visible ? 1.0 : 0.0,
duration: Duration(milliseconds: 500),
// The green box must be a child of the AnimatedOpacity widget.
child: Container(
width: 200.0,
height: 200.0,
color: Colors.green,
),
);
You can find more info and full code here: https://flutter.dev/docs/cookbook/animation/opacity-animation