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We have to wrap the widget we want to show or hide inside the visibility widget as a child. This widget has a property called visible which controls the state (visible or invisible) of the child. Instead of hiding the child, we can also replace it with another widget.
To programmatically show hide widgets in Flutter using Visibility widget, simply wrap your widget inside the Visibility widget and then control its visibility using the variable. You can set the variable value from anywhere and then rebuilding the screen shows or hides the widget.
Click the Layout tab, if necessary. By default, the Layout tab is selected. In the Screen Outline panel, which provides the hierarchical representation of the screen, select the widget that you want to hide. Select the Hide check box.
You can use Opacity with an opacity: of 0.0 to draw make an element hidden but still occupy space. To make it not occupy space, replace it with an empty Container() . Thank you!
Invisible: The widget takes physical space on the screen but not visible to user.
Gone: The widget doesn't take any physical space and is completely gone.
Invisible example
Visibility(
child: Text("Invisible"),
maintainSize: true,
maintainAnimation: true,
maintainState: true,
visible: false,
),
Gone example
Visibility(
child: Text("Gone"),
visible: false,
),
You can also use if or if-else.
Using if
Column(
children: <Widget>[
Text('Good Morning'), // Always visible
if (hasName) Text(' Mr ABC'), // Visible only if 'hasName' is true
],
)
Using if-else
Column(
children: <Widget>[
// Only one of them is visible based on 'isMorning' condition.
if (isMorning) Text('Good Morning')
else Text ('Good Evening'),
],
)
UPDATE: Since this answer was written, Visibility was introduced and provides the best solution to this problem.
You can use Opacity with an opacity: of 0.0 to draw make an element hidden but still occupy space.
To make it not occupy space, replace it with an empty Container().
EDIT: To wrap it in an Opacity object, do the following:
new Opacity(opacity: 0.0, child: new Padding(
padding: const EdgeInsets.only(
left: 16.0,
),
child: new Icon(pencil, color: CupertinoColors.activeBlue),
))
Google Developers quick tutorial on Opacity: https://youtu.be/9hltevOHQBw
To collaborate with the question and show an example of replacing it with an empty Container().
Here's the example below:
import "package:flutter/material.dart";
void main() {
runApp(new ControlleApp());
}
class ControlleApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: "My App",
home: new HomePage(),
);
}
}
class HomePage extends StatefulWidget {
@override
HomePageState createState() => new HomePageState();
}
class HomePageState extends State<HomePage> {
bool visibilityTag = false;
bool visibilityObs = false;
void _changed(bool visibility, String field) {
setState(() {
if (field == "tag"){
visibilityTag = visibility;
}
if (field == "obs"){
visibilityObs = visibility;
}
});
}
@override
Widget build(BuildContext context){
return new Scaffold(
appBar: new AppBar(backgroundColor: new Color(0xFF26C6DA)),
body: new ListView(
children: <Widget>[
new Container(
margin: new EdgeInsets.all(20.0),
child: new FlutterLogo(size: 100.0, colors: Colors.blue),
),
new Container(
margin: new EdgeInsets.only(left: 16.0, right: 16.0),
child: new Column(
children: <Widget>[
visibilityObs ? new Row(
crossAxisAlignment: CrossAxisAlignment.end,
children: <Widget>[
new Expanded(
flex: 11,
child: new TextField(
maxLines: 1,
style: Theme.of(context).textTheme.title,
decoration: new InputDecoration(
labelText: "Observation",
isDense: true
),
),
),
new Expanded(
flex: 1,
child: new IconButton(
color: Colors.grey[400],
icon: const Icon(Icons.cancel, size: 22.0,),
onPressed: () {
_changed(false, "obs");
},
),
),
],
) : new Container(),
visibilityTag ? new Row(
crossAxisAlignment: CrossAxisAlignment.end,
children: <Widget>[
new Expanded(
flex: 11,
child: new TextField(
maxLines: 1,
style: Theme.of(context).textTheme.title,
decoration: new InputDecoration(
labelText: "Tags",
isDense: true
),
),
),
new Expanded(
flex: 1,
child: new IconButton(
color: Colors.grey[400],
icon: const Icon(Icons.cancel, size: 22.0,),
onPressed: () {
_changed(false, "tag");
},
),
),
],
) : new Container(),
],
)
),
new Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new InkWell(
onTap: () {
visibilityObs ? null : _changed(true, "obs");
},
child: new Container(
margin: new EdgeInsets.only(top: 16.0),
child: new Column(
children: <Widget>[
new Icon(Icons.comment, color: visibilityObs ? Colors.grey[400] : Colors.grey[600]),
new Container(
margin: const EdgeInsets.only(top: 8.0),
child: new Text(
"Observation",
style: new TextStyle(
fontSize: 12.0,
fontWeight: FontWeight.w400,
color: visibilityObs ? Colors.grey[400] : Colors.grey[600],
),
),
),
],
),
)
),
new SizedBox(width: 24.0),
new InkWell(
onTap: () {
visibilityTag ? null : _changed(true, "tag");
},
child: new Container(
margin: new EdgeInsets.only(top: 16.0),
child: new Column(
children: <Widget>[
new Icon(Icons.local_offer, color: visibilityTag ? Colors.grey[400] : Colors.grey[600]),
new Container(
margin: const EdgeInsets.only(top: 8.0),
child: new Text(
"Tags",
style: new TextStyle(
fontSize: 12.0,
fontWeight: FontWeight.w400,
color: visibilityTag ? Colors.grey[400] : Colors.grey[600],
),
),
),
],
),
)
),
],
)
],
)
);
}
}
Flutter now contains a Visibility Widget that you should use to show/hide widgets. The widget can also be used to switch between 2 widgets by changing the replacement.
This widget can achieve any of the states visible, invisible, gone and a lot more.
Visibility(
visible: true //Default is true,
child: Text('Ndini uya uya'),
//maintainSize: bool. When true this is equivalent to invisible;
//replacement: Widget. Defaults to Sizedbox.shrink, 0x0
),
Try the Offstage widget
if attribute offstage:true the not occupy the physical space and invisible,
if attribute offstage:false it will occupy the physical space and visible
Offstage(
offstage: true,
child: Text("Visible"),
),
You can encapsulate any widget in your code with a new widget called (Visibility), this is from the yellow lamp at the very left side of the widget that you want it to be in-visible
example: say you want to make a row invisible:
The Child of the newly created widget (Visibility Widget) is the Widget that you want it to be invisible
Visibility(
visible: false,
child: Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
SizedBox(
width: 10,
),
Text("Search",
style: TextStyle(fontSize: 20
),),
],
),
),
I hope it will help someone in the future
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