dart

问题 I want to build a PWA based on flutter web which relies on scanning a QR-Code and accessing the user's current position. From my point of knowledge for both functionalities there are currently no packages available. However for getting the user's location there is a stackoverflow thread (Get User's Location for flutter Web) providing a solution. So I'm wondering if there is any chance that there is a similar solution for the QR-Scanning issue? Sadly, I'm not very familiar with web and

问题 Here i am trying to load image link from firebase into flutter app then passing it into image.network(). the data loading is taking time to load data so it is giving me following error: RangeError (index): Invalid value: Valid value range is empty: 1 but after 5 second the data is loaded successfully and printed in console but not displayed on screen. here is code to print data class _DataFetching extends State<MyHomePage> { List<eyes> allCriminals=eyes.allcriminals(); @override Widget build

问题 I have problem when trying to install the flutter in my desktop first I get error of : is not recognized as an internal or external command operable program or batch file. Then I open the system environment variable and add the flutter to the user variables path plus I add all of the flutter, git, system32 to systems variables path section. Unfortunately, the problem is still present even with a restart. Now when I type flutter doctor to Command prompt No results are shown and I cannot write

问题 I'm quite new to Firebase Flutter. I'm developing a mobile application to share books among others. In firebase firestore, I have 'users' collections which contain all the user data with unique id I have 'books' collection which contain all the book data with unique id created automatically Also I have 'global' collection with single document with one integer field called 'bookcount'. Users can can have many books. Now I want to create a another unique id field for book. idea is to have

问题 I have been trying to load static data into ListViewBuilder I successfully achieved the functionality using the same code given below but now it ain't working. LIST VIEW BUILDER ListView.builder( scrollDirection: Axis.horizontal, shrinkWrap: true, itemCount: allProducts.length==null ? 0 : allProducts.length, itemBuilder: (BuildContext ctxt, int index) { return new CustomCardProduct( product:allProducts[index], onPress: (){ ); }, ); }, ), STATIC DATA AND CLASS STORED IN USER.DART FILE. List

问题 I have been trying to load static data into ListViewBuilder I successfully achieved the functionality using the same code given below but now it ain't working. LIST VIEW BUILDER ListView.builder( scrollDirection: Axis.horizontal, shrinkWrap: true, itemCount: allProducts.length==null ? 0 : allProducts.length, itemBuilder: (BuildContext ctxt, int index) { return new CustomCardProduct( product:allProducts[index], onPress: (){ ); }, ); }, ), STATIC DATA AND CLASS STORED IN USER.DART FILE. List

问题 I'm quite new to Firebase Flutter. I'm developing a mobile application to share books among others. In firebase firestore, I have 'users' collections which contain all the user data with unique id I have 'books' collection which contain all the book data with unique id created automatically Also I have 'global' collection with single document with one integer field called 'bookcount'. Users can can have many books. Now I want to create a another unique id field for book. idea is to have

问题 I'm fairly new to Dart and Flutter, and I'm having trouble to overwrite an existing assets image from a source image. My attempt: try { File localFile = File('assets/images/myImage.png'); localFile.writeAsBytesSync(originFile.readAsBytesSync()); catch (e) { log(e.toString()); } I get: [log] FileSystemException: Cannot open file, path = 'assets/images/myImage.png' (OS Error: No such file or directory, errno = 2) I did define the assets folder in pubspec.yaml : assets: - assets/images/ Ok, so I

问题 I'm fairly new to Dart and Flutter, and I'm having trouble to overwrite an existing assets image from a source image. My attempt: try { File localFile = File('assets/images/myImage.png'); localFile.writeAsBytesSync(originFile.readAsBytesSync()); catch (e) { log(e.toString()); } I get: [log] FileSystemException: Cannot open file, path = 'assets/images/myImage.png' (OS Error: No such file or directory, errno = 2) I did define the assets folder in pubspec.yaml : assets: - assets/images/ Ok, so I

问题 I'm fairly new to Dart and Flutter, and I'm having trouble to overwrite an existing assets image from a source image. My attempt: try { File localFile = File('assets/images/myImage.png'); localFile.writeAsBytesSync(originFile.readAsBytesSync()); catch (e) { log(e.toString()); } I get: [log] FileSystemException: Cannot open file, path = 'assets/images/myImage.png' (OS Error: No such file or directory, errno = 2) I did define the assets folder in pubspec.yaml : assets: - assets/images/ Ok, so I