I'm building an app which requires data from a page to the previous page. I'm using Navigator.pop(context); to exit from the current page at the same time refreshing the previous page with a function. I need to pass an ID to the previous page for an API calling. How can I pass a data by Navigagtor.pop(context).
Try below code: Navigator.pop(context, 'Back!');
ElevatedButton(
onPressed: () {
Navigator.pop(context, 'You are old screen!');
},
child: const Text('Back Screen!'),
),
Refer Return data from a screen
From the First Page you can navigate to Second one. The "Navigator.push" returns a Future. Use "then" to get the value returned from Second page.
Navigator.push(context, MaterialPageRoute(builder: (context) => SecondPage())).then((value) {
// Handle 'value' here.
// 'value' is returned by second page through Navigator.pop(context, 'some relevante value or object');
});
Related
I have the following flow Screen 1 -> Screen 2 -> Dialog (in a separate widget).
Screen 2 displays a dialog (Close? Yes or No). If someone presses Yes, I would like to return to the Screen 1, if they press No, just close the dialog and return to Screen 2. What I currently do is when Yes is tapped, I do Navigator.pop(context) twice. Is this a good practice? Is there a way to pass the context of Screen 2 to my dialog widget so I can pop that one directly?
Personally, I think it would be better to pass the response from the dialog back to the page, and let the page handle the rest.
You can do this:
//I'm using a raised button just to call the alert as an example...
RaisedButton(
child: Text('Press me'),
//This part here is the important part
onPressed: () async {
//You can return anything when you use Navigator.pop
//In this case I'm returning a bool indicating if the page should close or not.
//You have to await this because it depends on user input.
bool shouldPopResult = await showDialog<bool>(
context: context,
builder: (context) => AlertDialog(
//The content of your dialog
actions: <Widget>[
// The value you pass here in Navigator.of(context).pop
// is the value that will be stored in shouldPopResult,
// so if "Yes" is pressed, true will return...
// and if "No", false is returned.
FlatButton(
child: Text('Yes'),
onPressed: () => Navigator.of(context).pop(true),
),
FlatButton(
child: Text('No'),
onPressed: () => Navigator.of(context).pop(false),
)
],
),
);
// This is for if the user dismisses the dialog without pressing a button
// In that case shouldPopResult would be null, so I'm setting it to false.
// You can prevent the user from dismissing the dialog
// setting barrierDismissible to false in the showDialog method.
if (shouldPopResult == null) shouldPopResult = false;
// And finally with the dialog already dismissed, you can decide
// to go back or not.
if (shouldPopResult) Navigator.of(context).pop();
});
As usual you can extract the dialog as a Widget, or extract the function that handles the dialog response altogether or anything else.
You can see the example of returning data from a page in the flutter documentation here.
1.FlatButton(
onPressed: () async {
var typedName=await Navigator.push(
context,
MaterialPageRoute(
builder: (context) {
return CityScreen();
},
),
);
print(typedName); //prints the value of cityName
}
2. FlatButton(
onPressed: () {
Navigator.pop(context, cityName);
},
The no.1 is coming from file loading_screen and no.2 is coming from city_screen. Can you anyone help me understand what is happening that when you pass a variable or anything in the pop? And when come that onPress method is still working because the the method Navigator.push has been already assigned to the variable but still that method Navigator.push is working when I pressed the button?Does that onPress doesn't care about the variable TypedName and just looks for the method Navigator.push?
If you use push method it will create the new screen over your current page and pop will remove last screen, you cannot pass name with both, you can check basics of navigation here, if you want to pass name to next page you should use something like pushnamed method and you can see the logic of passing name here. And for all methods you should check here.
When calling Navigator.pop() a result can be passed to the previous screen. Is there a way to set the result so that if the user navigates back on their own the result is still returned to the previous page?
I could pass an object to the second page and then modify it so that the first page can check it when the second page returns, but I'd rather use the result returned from the Navigator as it's more readable.
Overriding the back button's tap detector as I've seen suggested elsewhere is not an acceptable solution because the user may navigate back in some other way such as swiping or pressing the Android back button.
Yes, you can pass data between screens both ways.
While popping back, send the data you wish to send like this from the second screen
RaisedButton(
onPressed: () {
// The Nope button returns "data" as the result.
Navigator.pop(context, 'data');
},
child: Text('Nope!'),
);
And catch the result in the your first screen like this
final result = await Navigator.push(
context,
MaterialPageRoute(builder: (context) => SecondScreen()),
);
source
For the other concern where the user is able to go back to the previous screen by pressing the back button, you can wrap your second screen with WillPopScope widget and provide the onWillPop callback. This will override the popping of the second screen and execute the callback where you can define the value you wish to return from the second screen.
#override
Widget build(BuildContext context) {
return WillPopScope(
child: Scaffold(), // or your widget
onWillPop: () {
return Future.delayed(Duration(microseconds: 0), () {
return Navigator.pop(context, "return-data");
});
},
);
}
Yes, this is possible, when navigating to Screen B from Screen A, make the onTap() functionasynchronous and await the result from Screen B.
Check the code below: It works perfectly:
On Screen A, put this code:
onTap: () async {
// receive the data you are sending from screen B here
final result = await Navigator.push( context);
},
On Screen B, put this code:
onTap: (){
// pass the data you want to use in screen A as the second paramter
Navigator.pop(context,number);
},
I hope this helps
I have a flutter activity that launches another activity with
Navigator.push(context, MaterialPageRoute(builder: (context) => Chat()));}
from the second activity I launch another activity using the same method
if from the third activity I press the back button it returns to the first activity and if I use
Navigator.pop(context);
it returns to the second activity
how do I make the back button return to the second activity?
Surround your second and third activities in the following way
WillPopScope(
onWillPop: () async {
Navigator.pop(context);
return false;
},
child: AnotherActivity(
…
),
);
I have a "list page". and an add page. User clicks "add page", goes to a new page where they add some entity. Then I pop the Navigator, and user goes back to "list page".
At this point, I want to get notified somehow - callback maybe? override a method, I am not really sure - and re-read the information from database.
Is there a hook like this in Flutter? Or is there another pattern that I should use?
The Navigator.push method returns a future of the generic type of the Route:
Navigator.of(context)
.push(new MaterialPageRoute<String>(...))
.then((String value) {
print(value);
});
And inside the new route, when you have the value you need:
Navigator.of(context).pop('String');
If at your list page, you create function let say retrieveData() to read list of the data then call it inside initState, if you're using pushNamed route, the simple solution would be
Navigator.pushNamed(context, '/adddatapage').whenComplete(retrieveData());
If you're using push route,
Navigator.of(context).push(new MaterialPageRoute(builder: (context) => AddPage())).whenComplete(retrieveData);
That should be enough. No need to additional code on the add page. This will be works if user press back button also, again, without additional code in the add page.
Adding a option to #ian 's answer
Navigator.of(context)
.push(new MaterialPageRoute<String>(...))
.then((value) => setState(() => {}));
This worked for me. This will rebuild whenever page is loaded.
Write below code when redirect to screen 2,
Navigator.pushNamed(context, '/screen2').then((_) {
// This block runs when you have returned back from screen 2.
setState(() {
// code here to refresh data
});
});
Use
Navigator.pop(context);
in screen 2 to back to screen 1
i use Navigator.pushAndRemoveUntil, it will refresh the page and load the data again, this is example :
Navigator.pushAndRemoveUntil(
context,
MaterialPageRoute(
builder: (context) =>
CustomerMainPage()),
(Route<dynamic> route) =>
false);
I passed a callback method into the "add" page as a Navigator route argument. The callback is a method in my list page. The "add" page executes the callback when exiting. The callback method then simply refreshes the data and calls setState to refresh the screen.
My architecture is using Provider and viewmodels, but it should be straight-forward in a standard app as well.
For named route:
Navigator.pushNamed(context, '/page2').then((_) {
// This block runs when you have returned back to the 1st Page from 2nd.
setState(() {
// Call setState to refresh the page.
});
});
For unnamed route:
Navigator.push(context, MaterialPageRoute(builder: (_) => Page2())).then((_) {
// This block runs when you have come back to the 1st Page from 2nd.
setState(() {
// Call setState to refresh the page.
});
});