Flutter ModalBottomSheet visibility - flutter

I want to call a function after modal bottom sheet built. But i could not check bottom sheet build. How can i check modal bottom sheet visibility and it is build?

showModalBottomSheet(context: context, builder: (context) => Container())
.then((value) => print('i am visible now!'));

Related

How to switch the screen smoothly?

I have three screens: 1, 2, and 3.
I want to switch from screen 2 to screen 3, but when I pop screen 2 and push screen 3, then it shows screen 1 for a while, then it shows screen 3, so is there any way to switch screens using pop after push or not?
this code not expectations
Navigator.push(
context,
MaterialPageRoute<Widget>(
builder: (context) => widget,
),
);
Navigator.pop(context);
Using pushReplacement insted of push
Navigator.pushReplacement(
context,
MaterialPageRoute<Widget>(
builder: (context) => widget,
),
);
Using pushReplacement insted of push
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (context) => widget,
),
);
The behavior you're describing is likely because when you call Navigator.pop(context), it removes the current screen (screen 2) from the navigation stack, but the framework hasn't yet had a chance to build and display the new screen (screen 3) that you pushed. So, for a brief moment, the previous screen (screen 1) is visible.
One way to switch screens without that flicker is to use Navigator.pushReplacement instead of Navigator.push followed by Navigator.pop. Navigator.pushReplacement removes the current screen from the navigation stack and replaces it with the new screen, all in one step.
Example:
Navigator.pushReplacement(
context,
MaterialPageRoute<Widget>(
builder: (context) => widget3,
),
);
This will directly switch from screen 2 to screen 3.
It is generally not recommended to use both Navigator.push() and Navigator.pop() together in the same function call, as this can cause unexpected behavior. Instead, you can use Navigator.replace() to replace the current screen with a new one, or use Navigator.pushNamedAndRemoveUntil() to push a new screen and remove all the screens that come before it.

Navigation in Flutter App - does not work as intended

I try to build a flutter app and want to navigate trough the pages.
I build a drawer with a menu with several items to open new pages - that works fine.
onTap: () {
Navigator.of(context).pop();
Navigator.push(
context,
new MaterialPageRoute(
builder: (BuildContext context) => new Page1(),
),
);
},
By pressing on the Page1 menuitem page1 opens fine.
Inside page1 I have a slidable list with "edit" and "details". I open this with
onTap: () {
Navigator.of(context).pop();
Navigator.push(
context,
MaterialPageRoute(
builder: (BuildContext context) => new DetailsPage(),
),
);
},
In the details Page I see all the things i wanna see, but when I press the Back button in the appBar i am back at home screen with closed drawer.
I tried to put onPressed: () => Navigator.pop(context); inside the appBar section but this doesn´t work either.
Now I got what I want by using always Navigator.push but I am sure that this is not right, so that navigator stack gets bigger and bigger.
What I do wrong? Why .pop does not bring me to the last page?
Any ideas?
Thx in advance
Patrick
Just remove the line with the Navigator.of(context).pop();in the Page1 onTap.
you can use pushReplacement in any cases you need to remove current page from stack and route to new page.
Replace the current route of the navigator that most tightly encloses
the given context by pushing the given route and then disposing the
previous route once the new route has finished animating in.
here is the documentation

Flutter back-pressed shows black screen

I have created NavigationDrawer in flutter before navigation drawer screen appear to user I have 3 screen before it
splash screen
intro slider
Login screen
NavigationDrawer
I want to close my app when user press back button in android phone from navigationdrawer screen but it will shows black screen.
I have called below called for navigation from login to drawer
Navigator.pushAndRemoveUntil(
context,
MaterialPageRoute(
builder: (BuildContext context) => NavigationDrawerDemo(),
),
ModalRoute.withName('/LoginFieldForm'));
I called loginfieldform with
Navigator.push(context,
new MaterialPageRoute(builder: (context) =>new LoginFieldForm()));
I think you have pushed the "LoginFieldForm" with the Navigator.push method and trying to remove it using the named routes.
For Ex :
// Puching a route with Navigator.push method
Navigator.push(
context,
MaterialPageRoute(builder: (context) => LoginFieldForm()),
);
// Removing using the named routes.
Navigator.pushAndRemoveUntil(
context,
MaterialPageRoute(
builder: (BuildContext context) => NavigationDrawerDemo(),
),
ModalRoute.withName('/LoginFieldForm'));
You can only use ModalRoute.withName() if you have added the route using named routes.
Your route probably has not a name set. If so, popping until the name is matched will result in popping everything, since the name you're looking for will never be found.
When you push LoginFieldForm ensure to pass a settings to the Route.
When pushing, you can do this:
MaterialPageRoute(
settings: RouteSettings(name: "routeName"),
builder: (context) => YourWidget(),
)
If you're within onGenerateRoute you already have settings passed as an argument to the onGenerateRoute function. In that case, just forward them to the MaterialPageRoute:
MaterialPageRoute(
settings: settings, //these settings are arguments from the function
builder: (context) => YourWidget(),
)
To close the app you may use exit(0) of dart:io on back press.exit(0) help out to Exit the Dart VM process immediately with the given exit code.
This does not wait for any asynchronous operations to terminate. You may find more information about exit(0) here
Or
SystemChannels.platform.invokeMethod('SystemNavigator.pop');
For more detail you may check here
Use-case: pushNamedAndRemoveUntil
Navigator.of(context).pushNamedAndRemoveUntil('/LoginFieldForm',
(Route<dynamic> route) => false);

Flutter:How to create a full screen mask view

Now I'm using the showModalBottomSheet,
when I click on the semi-transparent bottomsheet, it pops this view out, but what I want is that it doesn't respond to the user's click and still stays there, how do I do that?
How to create a full screen mask view?
If user click on - semi-transparent area - ModalBottomSheet won't close using - WillPopScope
showModalBottomSheet(
context: context,
builder: (context) {
return WillPopScope( // add this
onWillPop: () async => false,
child: Container()); // your code continues
});

Present modally in Flutter?

How to do a modal presentation of a route in Flutter?
I figured out how to navigate to a route using the usual "push" transition, but I am struggling to implement a modal transition. See animation attached (done using native iOS). How do I present a screen modally (a screen that itself can be pushed more screens to).
See an example below. The transition I am struggling with is from "A" to "C" (and of course a way to dismiss it and go back to "A").
You can push like this:
Navigator.of(context).push(
CupertinoPageRoute(
fullscreenDialog: true,
builder: (context) => SomePage(),
),
);
Hope this helps.
Go to Section B(push) animation can be achieved by following:
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => SectionBRoute()),
);
Go to Section C(present modally) animation can be achieved by following:
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => SectionCRoute(), fullscreenDialog: true),
);