dart-sdk

Display all images in a directory to a list in Flutter

由 ≯℡__Kan透↙ 提交于 2020-06-25 04:58:12
问题 I was wondering if there is a way i can display all images or files in a particular directory located in user's mobile device to a list/array in flutter so i can use in a ListView. Thanks any help is welcomed. PS: i wanted to try with path_provider but didn't know how to. 回答1: I was able to find a solution. I had to work with MethodChannels in other to achieve this. After writing the java code for getting the file list, i passed in into flutter through a channel Java Method for getting files

Flutter lower dart version

由 百般思念 提交于 2019-12-23 09:32:46
问题 I'm getting the following error due to Dart version of my flutter setup when I run the flutter get packages command: [project_name] flutter packages get Running "flutter packages get" in project_name... The current Dart SDK version is 2.1.0-dev.0.0.flutter-be6309690f. Because project depends on intl_translation >=0.14.0+1 <0.17.0 which requires SDK version >=1.12.0 <2.0.0, version solving failed. pub get failed (1) exit code 1 My framework version: Flutter 0.6.0 • channel beta • https:/

What does Underscore “_” before variable name mean for Flutter

由 僤鯓⒐⒋嵵緔 提交于 2019-12-18 03:03:34
问题 with reference to the Flutter tutorial, I encountered an underscore, _ . I know that in Java, _ is used as a naming convention for a private variable. Does it also apply to Flutter? Noting that there is no public/protected in Flutter. Will the _ really be private (inaccessible by other classes) or is it just a naming convention? Variable class RandomWordsState extends State<RandomWords> { final List<WordPair> _suggestions = <WordPair>[]; final Set<WordPair> _saved = new Set<WordPair>(); final

What means in Dart static type and why it differs with runtime type?

由 ﹥＞﹥吖頭↗ 提交于 2019-12-12 20:58:00
问题 In Dart exists two kind of types. Runtime type Static type Here is proof in Dart language specification: The static type of null is bottom. Runtime type of null is Null Static type of null is bottom This mean that objects in Dart can have two kind of types. One real type that called static and one virtual type that called runtime . That is, runtime type of null is not a bottom but a regular class Null . class Null { factory Null._uninstantiable() { throw new UnsupportedError('class Null

Dart 2.3 ignores breakpoints

由 China☆狼群 提交于 2019-12-11 17:25:28
问题 I am developing a web app in Dart using Webstorm as IDE. After upgrading from Dart SDK 2.2 to Dart SDK 2.3 I noticed that all breakpoints I set in Webstorm are ignored (although the app seems to run properly in Chrome) That breakpoints are correctly marked as a "red circle" but unlike the previous SDK they miss the "tick" inside (which I think means they are not recognized by Chrome). I tried to "repair cache" and "upgrade dependencies" but breakpoints still don't work. That's the pubspec

What is the best way to track the state of an Isolate in Dart?

由 痞子三分冷 提交于 2019-12-07 21:06:23
问题 I'm trying to track whether the isolate is currently running or not (and in the future whether it has errored out) using isolate.addOnExitListener(...). However, the following snippet of code is not working how I would expect: items.forEach((name, item) async { Isolate isolate = await Isolate.spawnUri(...); item.status = "running"; ReceivePort receivePort = new ReceivePort(); isolate.addOnExitListener(receivePort.sendPort); receivePort.listen((message){ if (message == null) { print("Item

What is the best way to track the state of an Isolate in Dart?

由 本小妞迷上赌 提交于 2019-12-06 12:25:08
I'm trying to track whether the isolate is currently running or not (and in the future whether it has errored out) using isolate.addOnExitListener(...). However, the following snippet of code is not working how I would expect: items.forEach((name, item) async { Isolate isolate = await Isolate.spawnUri(...); item.status = "running"; ReceivePort receivePort = new ReceivePort(); isolate.addOnExitListener(receivePort.sendPort); receivePort.listen((message){ if (message == null) { print("Item exited: ${item.name}"); item.status = "stopped"; } }); }); The "items" map contains 3 values, each with a

What does Underscore “_” before variable name mean for Flutter

由 我的梦境 提交于 2019-11-29 05:39:12
with reference to the Flutter tutorial, I encountered an underscore, _ . I know that in Java, _ is used as a naming convention for a private variable. Does it also apply to Flutter? Noting that there is no public/protected in Flutter. Will the _ really be private (inaccessible by other classes) or is it just a naming convention? Variable class RandomWordsState extends State<RandomWords> { final List<WordPair> _suggestions = <WordPair>[]; final Set<WordPair> _saved = new Set<WordPair>(); final TextStyle _biggerFont = const TextStyle(fontSize: 18.0); ... } Does the _ make the Widget private too?
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