I am a flutter newbie tried creating a Snackbar by creating Global key call _scaffoldkey and appending it to the scaffold. I then tried tried creating a snack bar using this key but it isn't working, I got a feedback saying "NoSuchMethodError : The method 'showSnackBar' was called on null. Receiver : Null Tries calling : showSnackBar (Instance of 'SnackBar') Can someone please help?
final _scaffoldKey = GlobalKey<ScaffoldState>();
_displaySnackBar(BuildContext context) {
final snackBar = SnackBar(content: Text('Are you talkin\' to me?'));
_scaffoldKey.currentState.showSnackBar(snackBar);
}
return Scaffold(
key: _scaffoldKey,
body: SingleChildScrollView(
child: Column(
children: <Widget>[
SafeArea(
child: Container(
width: width,
child: Column(
children: <Widget>[
Hero(
tag: 'h' + index.toString(),
child: Stack(
children: <Widget>[
Container(
height: height * (0.4),
child: CachedNetworkImage(
width: width,
height: height * (0.4),
fit: BoxFit.fill,
imageUrl: imageUrl,
placeholder: (context, url) => spinKit(),
errorWidget: (context, url, error) => Container(
constraints: BoxConstraints.expand(),
child: Container(
alignment: Alignment.topLeft,
color: Colors.blue,
child: Center(child: Icon(Icons.error)),
)),
),
),
SafeArea(
child: Container(
alignment: Alignment.topLeft,
padding: const EdgeInsets.all(5),
child: Icon(
Icons.arrow_back_ios,
size: 40,
color: Colors.white,
),
),
),
],
),
),
Container(
alignment: Alignment.bottomCenter,
child: Container(
width: width,
color: Colors.black,
child: Row(
children: <Widget>[
GestureDetector(
onTap: overFlowRight
? () {
Navigator.of(context)
.push(_createRoute2(_devotionNotifier, index + 1));
}
: _displaySnackBar(context),
child: Container(
padding: const EdgeInsets.only(left: 5),
child: Icon(
Icons.arrow_left,
size: 50,
color: Colors.white,
),
),
),
Expanded(
child: Padding(
padding: EdgeInsets.only(left: 0, right: 0),
child: Text(
_devotionNotifier.devotionList[index].topic,
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 30.0,
fontFamily: 'Pacifico',
color: Colors.white,
),
),
),
),
GestureDetector(
onTap: overFlowLeft
? () {
Navigator.of(context)
.push(_createRoute(_devotionNotifier, index - 1));
}
: _displaySnackBar(context),
child: Container(
padding: const EdgeInsets.only(right: 5),
child: Icon(
Icons.arrow_right,
size: 50,
color: Colors.white,
),
),
),
],
)
),
)
],
),
),
),
Row(
children: <Widget>[
Expanded(
child: Container(
alignment: Alignment.centerLeft,
padding: const EdgeInsets.all(10),
child: Text(
'Memory Verse :' +
_devotionNotifier.devotionList[index].verse,
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 15.0,
fontFamily: 'Merriweather',
color: Colors.grey,
),
),
),
),
SizedBox(
width: 25,
),
Expanded(
child: Container(
alignment: Alignment.centerRight,
padding: const EdgeInsets.all(10),
child: Text(
'Date :' + _devotionNotifier.devotionList[index].time,
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 15.0,
fontFamily: 'Merriweather',
color: Colors.grey,
),
),
),
),
],
),
Padding(
padding:
const EdgeInsets.only(left: 12, right: 12, bottom: 20, top: 12),
child: Center(
child: Text(
_devotionNotifier.devotionList[index].content,
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 20.0,
fontWeight: FontWeight.w600,
fontFamily: 'Bellota',
color: Colors.black,
),
),
),
),
],
),
));
In onTap function of GestureDetector you forgot braces in else condition.I added ()=> Try this:
final _scaffoldKey = GlobalKey<ScaffoldState>();
_displaySnackBar(BuildContext context) {
final snackBar = SnackBar(content: Text('Are you talkin\' to me?'));
_scaffoldKey.currentState.showSnackBar(snackBar);
}
return Scaffold(
key: _scaffoldKey,
body: SingleChildScrollView(
child: Column(
children: <Widget>[
SafeArea(
child: Container(
width: width,
child: Column(
children: <Widget>[
Hero(
tag: 'h' + index.toString(),
child: Stack(
children: <Widget>[
Container(
height: height * (0.4),
child: CachedNetworkImage(
width: width,
height: height * (0.4),
fit: BoxFit.fill,
imageUrl: imageUrl,
placeholder: (context, url) => spinKit(),
errorWidget: (context, url, error) => Container(
constraints: BoxConstraints.expand(),
child: Container(
alignment: Alignment.topLeft,
color: Colors.blue,
child: Center(child: Icon(Icons.error)),
)),
),
),
SafeArea(
child: Container(
alignment: Alignment.topLeft,
padding: const EdgeInsets.all(5),
child: Icon(
Icons.arrow_back_ios,
size: 40,
color: Colors.white,
),
),
),
],
),
),
Container(
alignment: Alignment.bottomCenter,
child: Container(
width: width,
color: Colors.black,
child: Row(
children: <Widget>[
GestureDetector(
onTap: overFlowRight
? () {
Navigator.of(context)
.push(_createRoute2(_devotionNotifier, index + 1));
}
: ()=> _displaySnackBar(context),
child: Container(
padding: const EdgeInsets.only(left: 5),
child: Icon(
Icons.arrow_left,
size: 50,
color: Colors.white,
),
),
),
Expanded(
child: Padding(
padding: EdgeInsets.only(left: 0, right: 0),
child: Text(
_devotionNotifier.devotionList[index].topic,
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 30.0,
fontFamily: 'Pacifico',
color: Colors.white,
),
),
),
),
GestureDetector(
onTap: overFlowLeft
? () {
Navigator.of(context)
.push(_createRoute(_devotionNotifier, index - 1));
}
: ()=> _displaySnackBar(context),
child: Container(
padding: const EdgeInsets.only(right: 5),
child: Icon(
Icons.arrow_right,
size: 50,
color: Colors.white,
),
),
),
],
)
),
)
],
),
),
),
Row(
children: <Widget>[
Expanded(
child: Container(
alignment: Alignment.centerLeft,
padding: const EdgeInsets.all(10),
child: Text(
'Memory Verse :' +
_devotionNotifier.devotionList[index].verse,
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 15.0,
fontFamily: 'Merriweather',
color: Colors.grey,
),
),
),
),
SizedBox(
width: 25,
),
Expanded(
child: Container(
alignment: Alignment.centerRight,
padding: const EdgeInsets.all(10),
child: Text(
'Date :' + _devotionNotifier.devotionList[index].time,
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 15.0,
fontFamily: 'Merriweather',
color: Colors.grey,
),
),
),
),
],
),
Padding(
padding:
const EdgeInsets.only(left: 12, right: 12, bottom: 20, top: 12),
child: Center(
child: Text(
_devotionNotifier.devotionList[index].content,
textAlign: TextAlign.center,
style: TextStyle(
fontSize: 20.0,
fontWeight: FontWeight.w600,
fontFamily: 'Bellota',
color: Colors.black,
),
),
),
),
],
),
));