usage of generics in flutter dart
Can somebody explain the usage of <MyApp> ?
MyAppState is extended of State class , but what is MyApp?
I know OOP in php but can't understand this one.
class MyApp extends StatefulWidget{
@override
MyAppState createState() => new MyAppState();
}
class MyAppState extends State<MyApp>{
@override
Widget build(BuildContext context) {
return new Scaffold(...);
}
}
dart 
flutter asked Nov 18 '18 at 20:19
danial dezfoulidanial dezfouli
61
add a comment |
Can somebody explain the usage of <MyApp> ?
MyAppState is extended of State class , but what is MyApp?
I know OOP in php but can't understand this one.
class MyApp extends StatefulWidget{
@override
MyAppState createState() => new MyAppState();
}
class MyAppState extends State<MyApp>{
@override
Widget build(BuildContext context) {
return new Scaffold(...);
}
}
asked Nov 18 '18 at 20:19
danial dezfoulidanial dezfouli
61
Check this post, it's perfect to understand what you need: medium.com/flutter-community/…
– diegoveloper
Nov 18 '18 at 20:31
add a comment |
Can somebody explain the usage of <MyApp> ?
MyAppState is extended of State class , but what is MyApp?
I know OOP in php but can't understand this one.
class MyApp extends StatefulWidget{
@override
MyAppState createState() => new MyAppState();
}
class MyAppState extends State<MyApp>{
@override
Widget build(BuildContext context) {
return new Scaffold(...);
}
}
asked Nov 18 '18 at 20:19
danial dezfoulidanial dezfouli
61
Can somebody explain the usage of <MyApp> ?
MyAppState is extended of State class , but what is MyApp?
I know OOP in php but can't understand this one.
class MyApp extends StatefulWidget{
@override
MyAppState createState() => new MyAppState();
}
class MyAppState extends State<MyApp>{
@override
Widget build(BuildContext context) {
return new Scaffold(...);
}
}
asked Nov 18 '18 at 20:19
danial dezfoulidanial dezfouli
61
asked Nov 18 '18 at 20:19
danial dezfoulidanial dezfouli
61
asked Nov 18 '18 at 20:19
danial dezfoulidanial dezfouli
61
asked Nov 18 '18 at 20:19
danial dezfoulidanial dezfouli
61
asked Nov 18 '18 at 20:19
danial dezfoulidanial dezfouli
61
61
Check this post, it's perfect to understand what you need: medium.com/flutter-community/…
– diegoveloper
Nov 18 '18 at 20:31
add a comment |
Check this post, it's perfect to understand what you need: medium.com/flutter-community/…
– diegoveloper
Nov 18 '18 at 20:31
Check this post, it's perfect to understand what you need: medium.com/flutter-community/…
– diegoveloper
Nov 18 '18 at 20:31
Check this post, it's perfect to understand what you need: medium.com/flutter-community/…
– diegoveloper
Nov 18 '18 at 20:31
add a comment |
3 Answers
3
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oldest
votes
State<MyApp> is a State class that is specialized for the MyApp class. This allows it to have inheritable methods and properties that operate on or involve a MyApp widget.
For example, it allows MyAppState.widget to return the corresponding widget specifically as a MyApp widget instead of as a generic StatefulWidget. This is important if you then wanted to call MyApp-specific properties or methods on the returned widget.
Note that this is necessary because Flutter uses type-safe Dart and tries to do as much static type-checking as possible to minimize the cost of doing type-checking at runtime.
answered Nov 18 '18 at 21:16
jamesdlinjamesdlin
26.2k65992
add a comment |
<MyApp> is a type parameter of generic type State<T>. Not sure whether php has generics, but essentially generics allows you to reuse 'generic' code over a range of different types and in the meantime it provides more type safety e.g. generics prevents you accidentally adding a double to a list of int (List<int>) for example. A native example, again, would be generic list List<T> where the same operation like add item to a list can be applied to a list of int (List<int>) or a list of people or a list of anything.
Maybe check out this for generics in dart specifically.
answered Nov 18 '18 at 21:18
stt106stt106
1,2191024
add a comment |
Always remember that State<T> class is implemented as a generic class
when you extend any generic class you have to specify the type for it which happen to be your statful widget concrete implementation and its name is MyApp
for every concrete implementation for the StatfulWidget class you need to define another concrete implementation of a class extending State<MyApp> and its name is MyAppState because State<T> is a generic class we code it as State<MyApp>
so as answer to your question
MyApp is the name of the concrete implementation of the class StatefulWidget
StatefulWidget -----> class not generic
MyApp -------------> concrete implementation for StatefulWidget class
State -----------> generic class of
MyAppState --> concrete implementation for State
Hope that help ..
answered Nov 18 '18 at 22:02
Saed NabilSaed Nabil
1,17828
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
State<MyApp> is a State class that is specialized for the MyApp class. This allows it to have inheritable methods and properties that operate on or involve a MyApp widget.
For example, it allows MyAppState.widget to return the corresponding widget specifically as a MyApp widget instead of as a generic StatefulWidget. This is important if you then wanted to call MyApp-specific properties or methods on the returned widget.
Note that this is necessary because Flutter uses type-safe Dart and tries to do as much static type-checking as possible to minimize the cost of doing type-checking at runtime.
answered Nov 18 '18 at 21:16
jamesdlinjamesdlin
26.2k65992
add a comment |
State<MyApp> is a State class that is specialized for the MyApp class. This allows it to have inheritable methods and properties that operate on or involve a MyApp widget.
For example, it allows MyAppState.widget to return the corresponding widget specifically as a MyApp widget instead of as a generic StatefulWidget. This is important if you then wanted to call MyApp-specific properties or methods on the returned widget.
Note that this is necessary because Flutter uses type-safe Dart and tries to do as much static type-checking as possible to minimize the cost of doing type-checking at runtime.
answered Nov 18 '18 at 21:16
jamesdlinjamesdlin
26.2k65992
add a comment |
State<MyApp> is a State class that is specialized for the MyApp class. This allows it to have inheritable methods and properties that operate on or involve a MyApp widget.
For example, it allows MyAppState.widget to return the corresponding widget specifically as a MyApp widget instead of as a generic StatefulWidget. This is important if you then wanted to call MyApp-specific properties or methods on the returned widget.
Note that this is necessary because Flutter uses type-safe Dart and tries to do as much static type-checking as possible to minimize the cost of doing type-checking at runtime.
answered Nov 18 '18 at 21:16
jamesdlinjamesdlin
26.2k65992
State<MyApp> is a State class that is specialized for the MyApp class. This allows it to have inheritable methods and properties that operate on or involve a MyApp widget.
For example, it allows MyAppState.widget to return the corresponding widget specifically as a MyApp widget instead of as a generic StatefulWidget. This is important if you then wanted to call MyApp-specific properties or methods on the returned widget.
Note that this is necessary because Flutter uses type-safe Dart and tries to do as much static type-checking as possible to minimize the cost of doing type-checking at runtime.
answered Nov 18 '18 at 21:16
jamesdlinjamesdlin
26.2k65992
answered Nov 18 '18 at 21:16
jamesdlinjamesdlin
26.2k65992
answered Nov 18 '18 at 21:16
jamesdlinjamesdlin
26.2k65992
answered Nov 18 '18 at 21:16
jamesdlinjamesdlin
26.2k65992
26.2k65992
add a comment |
add a comment |
<MyApp> is a type parameter of generic type State<T>. Not sure whether php has generics, but essentially generics allows you to reuse 'generic' code over a range of different types and in the meantime it provides more type safety e.g. generics prevents you accidentally adding a double to a list of int (List<int>) for example. A native example, again, would be generic list List<T> where the same operation like add item to a list can be applied to a list of int (List<int>) or a list of people or a list of anything.
Maybe check out this for generics in dart specifically.
answered Nov 18 '18 at 21:18
stt106stt106
1,2191024
add a comment |
<MyApp> is a type parameter of generic type State<T>. Not sure whether php has generics, but essentially generics allows you to reuse 'generic' code over a range of different types and in the meantime it provides more type safety e.g. generics prevents you accidentally adding a double to a list of int (List<int>) for example. A native example, again, would be generic list List<T> where the same operation like add item to a list can be applied to a list of int (List<int>) or a list of people or a list of anything.
Maybe check out this for generics in dart specifically.
answered Nov 18 '18 at 21:18
stt106stt106
1,2191024
add a comment |
<MyApp> is a type parameter of generic type State<T>. Not sure whether php has generics, but essentially generics allows you to reuse 'generic' code over a range of different types and in the meantime it provides more type safety e.g. generics prevents you accidentally adding a double to a list of int (List<int>) for example. A native example, again, would be generic list List<T> where the same operation like add item to a list can be applied to a list of int (List<int>) or a list of people or a list of anything.
Maybe check out this for generics in dart specifically.
answered Nov 18 '18 at 21:18
stt106stt106
1,2191024
<MyApp> is a type parameter of generic type State<T>. Not sure whether php has generics, but essentially generics allows you to reuse 'generic' code over a range of different types and in the meantime it provides more type safety e.g. generics prevents you accidentally adding a double to a list of int (List<int>) for example. A native example, again, would be generic list List<T> where the same operation like add item to a list can be applied to a list of int (List<int>) or a list of people or a list of anything.
Maybe check out this for generics in dart specifically.
answered Nov 18 '18 at 21:18
stt106stt106
1,2191024
answered Nov 18 '18 at 21:18
stt106stt106
1,2191024
answered Nov 18 '18 at 21:18
stt106stt106
1,2191024
answered Nov 18 '18 at 21:18
stt106stt106
1,2191024
1,2191024
add a comment |
add a comment |
Always remember that State<T> class is implemented as a generic class
when you extend any generic class you have to specify the type for it which happen to be your statful widget concrete implementation and its name is MyApp
for every concrete implementation for the StatfulWidget class you need to define another concrete implementation of a class extending State<MyApp> and its name is MyAppState because State<T> is a generic class we code it as State<MyApp>
so as answer to your question
MyApp is the name of the concrete implementation of the class StatefulWidget
StatefulWidget -----> class not generic
MyApp -------------> concrete implementation for StatefulWidget class
State -----------> generic class of
MyAppState --> concrete implementation for State
Hope that help ..
answered Nov 18 '18 at 22:02
Saed NabilSaed Nabil
1,17828
add a comment |
Always remember that State<T> class is implemented as a generic class
when you extend any generic class you have to specify the type for it which happen to be your statful widget concrete implementation and its name is MyApp
for every concrete implementation for the StatfulWidget class you need to define another concrete implementation of a class extending State<MyApp> and its name is MyAppState because State<T> is a generic class we code it as State<MyApp>
so as answer to your question
MyApp is the name of the concrete implementation of the class StatefulWidget
StatefulWidget -----> class not generic
MyApp -------------> concrete implementation for StatefulWidget class
State -----------> generic class of
MyAppState --> concrete implementation for State
Hope that help ..
answered Nov 18 '18 at 22:02
Saed NabilSaed Nabil
1,17828
add a comment |
Always remember that State<T> class is implemented as a generic class
when you extend any generic class you have to specify the type for it which happen to be your statful widget concrete implementation and its name is MyApp
for every concrete implementation for the StatfulWidget class you need to define another concrete implementation of a class extending State<MyApp> and its name is MyAppState because State<T> is a generic class we code it as State<MyApp>
so as answer to your question
MyApp is the name of the concrete implementation of the class StatefulWidget
StatefulWidget -----> class not generic
MyApp -------------> concrete implementation for StatefulWidget class
State -----------> generic class of
MyAppState --> concrete implementation for State
Hope that help ..
answered Nov 18 '18 at 22:02
Saed NabilSaed Nabil
1,17828
Always remember that State<T> class is implemented as a generic class
when you extend any generic class you have to specify the type for it which happen to be your statful widget concrete implementation and its name is MyApp
for every concrete implementation for the StatfulWidget class you need to define another concrete implementation of a class extending State<MyApp> and its name is MyAppState because State<T> is a generic class we code it as State<MyApp>
so as answer to your question
MyApp is the name of the concrete implementation of the class StatefulWidget
StatefulWidget -----> class not generic
MyApp -------------> concrete implementation for StatefulWidget class
State -----------> generic class of
MyAppState --> concrete implementation for State
Hope that help ..
answered Nov 18 '18 at 22:02
Saed NabilSaed Nabil
1,17828
edited Nov 18 '18 at 22:36
answered Nov 18 '18 at 22:02
Saed NabilSaed Nabil
1,17828
answered Nov 18 '18 at 22:02
Saed NabilSaed Nabil
1,17828
answered Nov 18 '18 at 22:02
Saed NabilSaed Nabil
1,17828
1,17828
add a comment |
add a comment |
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Check this post, it's perfect to understand what you need: medium.com/flutter-community/…
– diegoveloper
Nov 18 '18 at 20:31