On my Home widget, when user taps system back button, It shows by a WillPopScope a confirmation dialog widget.
I want to test this dialog but I cant figure it out how to press the back button on a test file.
I had the same problem but i had no back button in my app. I wanted to test the android system back button. This is how I did it. Maybe it's helpful for people who run into the same problem as me.
testWidgets("test onWillPop",(WidgetTester tester) async {
bool willPopCalled = false;
await tester.pumpWidget(
MaterialApp(
home: Scaffold(
body: WillPopScope(
onWillPop: () async {
willPopCalled = true;
return false;
},
child: Container(),
),
),
),
);
final dynamic widgetsAppState = tester.state(find.byType(WidgetsApp));
await widgetsAppState.didPopRoute();
await tester.pump();
expect(willPopCalled, true);
});
Inspired by: https://github.com/flutter/flutter/blob/master/packages/flutter/test/material/will_pop_test.dart
I cant figure it out how to press the back button on a test file.
This will help you to see back button on appbar(top part of app). It will allow you to see back button via appbar
return WillPopScope(
onWillPop: _onWillPop,
child: Scaffold(
appBar: AppBar(
title: Text("Title"),
centerTitle: true,
leading: IconButton(
icon: Icon(Icons.arrow_back, color: Colors.black),
onPressed: () => _onWillPop(),
),
),
body: Body(),
),
);
_onWillPop will be your "confirmation dialog widget" for your question.
Apparently, you cannot access Navigator in the test. So my solution is to include BackButton somewhere in the pumped widget and to pop the page like this:
await tester.pumpWidget(MaterialApp(
home: Scaffold(
body: Container(
child: BackButton(),
),
),
));
...
await tester.pageBack();
Related
I have a DetailPage that must return something to the code that called it. The documentation Return data from a screen explains that you must call Navigator.pop(context, whateverYouMustReturn) on some button.
So far so good, but what happens if the user clicks on the back button on the AppBar instead?? How do I return something then??
PS I'm using Navigator 1.0, btw
Provide your own leading widget and override the callback.
AppBar(
leading: BackButton(
onPressed: () {
Navigator.of(context).pop(myData);
},
),
),
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
leading: Container(), //Make leading an empty container to hide the default back button
),
body: WillPopScope(
onWillPop: () async {
Navigator.pop(context); //This method returns future boolean, based on your condition you can either
return true; //allow you to go back or you can show a toast and restrict in this page
},
child: Container(), //Your details page widget instead of container
),
);
}
My users will navigate to screen 1, then screen 2 then screen 3.
When they click the back button on screen 3, depending upon a variable in that screen, I want the back button to either take them back to screen 2 or screen 1.
Note: the back button must be trigger by the user, I don't to pragmatically navigate back.
I thought I could use WillPopScope but that can only return a bool.
Widget build(BuildContext context) {
return WillPopScope(
onWillPop: () {
return true
},
child: Scaffold(
...
),
);
}
,
Here's an example:
return WillPopScope(
onWillPop: () async => true,
child: Scaffold(
appBar: AppBar(
automaticallyImplyLeading: true,
leading: IconButton(
icon: Icon(Icons.arrow_back),
onPressed: () {
_user.isRegistered
? Navigator.popUntil(context, (route) => route.isFirst) // Takes the user to the first page
: Navigator.push(context, MaterialPageRoute(builder: (context) => SecondRoute()));
},
),
I have bottom tab navigator that contains of A and B screens, inside B screen I have widget that navigate to C page and inside C page I want to add back arrow to go back to previous screen (B screen), so...
I have simple widget that the code looks like this
#override
Widget build(BuildContext context) {
return SafeArea(
child: Scaffold(
resizeToAvoidBottomPadding: false,
appBar: AppBar(
leading: IconButton(
icon: Icon(Icons.arrow_back),
onPressed: () => Navigator.of(context).pop(),
),
title: Text("XXX"),
centerTitle: true,
),
body: detail()));
}
the problem is whenever I click back arrow.. it turns to black screen... I don't get any idea what the problem is... so is there a way to go to my previous screen?
and this is how I ndo navigate from B screen to C page
InkWell(
onTap: () {Navigator.of(context).pushReplacement(MaterialPageRoute(
builder: (context) => new NextScreen(check: values)));
},
child: Text(
"Next...",
style: TextStyle(
fontSize: 13.0,
),
),
)
The reason why you see a blank screen is because you navigated using pushReplacement. What pushReplacement does it that it will navigate to the next screen without stacking itself to the route meaning that it will make the app forget that the last screen was your screen B. Try using Navigator.push() instead.
Here is an example:
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => ScreenC()),
);
}
I am using interceptor https://pub.dartlang.org/packages/back_button_interceptor to execute a method when the page 1 is back from page 2.
If I come back from page 2 to page 1 using device back button, the method is executed.
But if I come back from page 2 to page 1 using the arrow button at appBar I am not able to execute the method.
How can the back arrow button functionality default to the device back button?
You can surround your scaffold on Page 2 with WillPopScope, set onWillPop to false to prevent the page from being popped by the system and then add your own back button into the app bar's leading widget and perform your pop in there.
#override
Widget build(BuildContext context) {
return new WillPopScope(
onWillPop: () async => false,
child: new Scaffold(
appBar: new AppBar(
title: new Text("data"),
leading: new IconButton(
icon: new Icon(Icons.ac_unit),
onPressed: () => Navigator.of(context).pop(),
),
),
),
);
}
code for the answer from this post
Edit: Addition to Page 2 to control navigation
In addition to the above code you'll add the below code to page 2. Change
Navigator.of(context).pop()
to
Navigator.of(context).pop('upload_files')
Then in your page 1 where you navigate you'll await the navigation and use the result returned from the pop on page 2 and run your logic
var navigationResult = await Navigator.push(
context,
new MaterialPageRoute(
builder: (context) => Page2()));
if(navigationResult == 'upload_files') {
uploadFiles(); // Perform your custom functionality here.
}
The default back button in AppBar is BackButton widget from material.dart. You may create it manually and pass your own onPressed to do what you want:
return Scaffold(
appBar: AppBar(
leading: BackButton(onPressed: _onBackPressed),
title: Text('Title'),
),
body: Container(),
);
If you do not specify leading in AppBar, then it creates a BackButton with the handler that does Navigator.maybePop(context).
once i fill the form and submit it to Firebase,the code navigates me to my homepage but as soon as i press back button of my android phone, it send's user to previous form page with all previous filled data is available. i have tired using WillPopScope function to disable back button of my android phone but no response..
i have also created a function using willpopscope and called it in main but no result.
#override
Widget build(BuildContext context) {
return new WillPopScope(
onWillPop: () async =>false,
child: new Scaffold(
appBar: new AppBar(
title: new Text('Welcome'),
actions: <Widget>[
_onbackpressed(), //tried disabling the back button by calling this fucntion
new FlatButton(
child: new Text('Logout',
style: new TextStyle(fontSize: 17.0, color: Colors.white)),
onPressed: _signOut)
],
),
body: _showTodoList(),
floatingActionButton: FloatingActionButton(
onPressed: () {
signupPage(context);
},
tooltip: 'Increment',
child: Icon(Icons.add),
)
),
);
}
//extra funtion to disable the back button-
_onbackpressed(){
return new WillPopScope(
onWillPop: () async =>false,
child: new Container(width: 0.0,height: 0.0,),
);
}
//function used to send the user form to server
RaisedButton(
elevation: 7.0,
child: Text('Upload'),
textColor: Colors.white,
color: Colors.blue,
onPressed: () {
final StorageReference firebaseStorageRef =
FirebaseStorage.instance.ref().child(Username);
final StorageUploadTask task =
firebaseStorageRef.putFile(_image);
success(context);
},
),
//where success is a fuction
success(BuildContext context){
Navigator.of(context)
.push(MaterialPageRoute(builder:(context)=>Redirect() ));
}
Instead of pushing a new screen when the user submits the form, you should pop it, like this:
success(BuildContext context){
Navigator.of(context).pop();
}
The reason for this is because you have a stack of screens. When the user is done with one, you should send him back to where you want, instead of putting another one on the top and leaving the already used one on the stack.