dart

How to detect scroll position of ListView in Flutter

由 巧了我就是萌 提交于 2021-02-17 21:10:40
问题 I'm using ListView widget to show items as a list. In a window three, items viewing must the middle item place in the middle. So how can I detect position of ListView when scrolling stop? How to detect ListView Scrolling stopped? 回答1: I used NotificationListener that is a widget that listens for notifications bubbling up the tree. Then use ScrollEndNotification , which indicates that scrolling has stopped. For scroll position I used _scrollController that type is ScrollController . new

How to detect scroll position of ListView in Flutter

由 百般思念 提交于 2021-02-17 21:10:07
问题 I'm using ListView widget to show items as a list. In a window three, items viewing must the middle item place in the middle. So how can I detect position of ListView when scrolling stop? How to detect ListView Scrolling stopped? 回答1: I used NotificationListener that is a widget that listens for notifications bubbling up the tree. Then use ScrollEndNotification , which indicates that scrolling has stopped. For scroll position I used _scrollController that type is ScrollController . new

Flutter automatically update application when new version is available

由 狂风中的少年 提交于 2021-02-17 19:14:37
问题 How can I implement auto-updating of my application when a new version is released without using Google Play Store? I'm using JSON to check the version. 回答1: Actually, in June 2020, we have more possibilities with Flutter. Among them: 1. Make updates inside the app. Display two kinds of notifications if the app has the new version. Plugin - https://pub.dev/packages/in_app_update (works only on Android, iOS doesn't support such functionality) 2. When a newer app version is available in the app

Dart学习笔记（二）

由 帅比萌擦擦* 提交于 2021-02-17 16:22:13
1，一般而言，当我们定义一个字符串的时候，字符串要用单引号或者双引号括起来，单引号或者双引号的作用是一样的，如下： String str1 = '单引号' ; String str2 = "双引号" ; 当字符串有换行需求的时候，我们可以用 \n 来代表一个换行符，如下： String str1 = '单引号\n这是第二行了' ; print(str1); 打印结果如下： 单引号 这是第二行了 但是有没有一个更加可视化的定义可换行的字符串的方案呢，比如像下面这样直接换行： String str2 = "双引号 这是第二行了" ; print (str2); 运行之后我们发现，程序报错了。 其实， 在Dart中，除了单引号和双引号，还可以用三引号（即三个单引号或者三个双引号）来修饰字符串。 使用三引号修饰的字符串可以直接换行 ，如下所示： String str2 = '''双引号 这是第二行了''' ; print(str2); 运行之后打印结果如下： 双引号 这是第二行了 2，Dart中的 数组是List，字典是Map，可以通过is关键字来判断变量的类型 ，如下所示： var map2 = new Map (); map2[ 'name' ] = '李四' ; map2[ 'age' ] = 29 ; map2[ 'work' ] = [ '程序员' , '登山运动员' ];

Flutter setState of child widget without rebuilding parent

由 我的未来我决定 提交于 2021-02-17 15:43:10
问题 I have a parent that contain a listView and a floatingActionButton i would like to hide the floatingActionButton when the user starts scrolling i have managed to do this within the parent widget but this requires the list to be rebuilt each time. I have moved the floatingActionButton to a separate class so i can update the state and only rebuild that widget the problem i am having is passing the data from the ScrollController in the parent class to the child this is simple when doing it

Rounded bottom on appbar

由 限于喜欢 提交于 2021-02-17 15:33:49
问题 I want to make an appbar with a rounded bottom, like so: How would I go about implementing such an appbar? I have tried reading up on the documentation for CustomPainter, but I don't feel like that is the way to go. 回答1: In Flutter you can have custom shape in AppBar widget with shape property. AppBar( title: Text('My App'), shape: RoundedRectangleBorder( borderRadius: BorderRadius.vertical( bottom: Radius.circular(30), ), ), ), 回答2: You can use BoxDecoration to add border-radius and shadow

Rounded bottom on appbar

由 谁说我不能喝 提交于 2021-02-17 15:33:23
问题 I want to make an appbar with a rounded bottom, like so: How would I go about implementing such an appbar? I have tried reading up on the documentation for CustomPainter, but I don't feel like that is the way to go. 回答1: In Flutter you can have custom shape in AppBar widget with shape property. AppBar( title: Text('My App'), shape: RoundedRectangleBorder( borderRadius: BorderRadius.vertical( bottom: Radius.circular(30), ), ), ), 回答2: You can use BoxDecoration to add border-radius and shadow

Rounded bottom on appbar

由 邮差的信 提交于 2021-02-17 15:33:15
问题 I want to make an appbar with a rounded bottom, like so: How would I go about implementing such an appbar? I have tried reading up on the documentation for CustomPainter, but I don't feel like that is the way to go. 回答1: In Flutter you can have custom shape in AppBar widget with shape property. AppBar( title: Text('My App'), shape: RoundedRectangleBorder( borderRadius: BorderRadius.vertical( bottom: Radius.circular(30), ), ), ), 回答2: You can use BoxDecoration to add border-radius and shadow

How to get response body with request.send() in dart

由 别等时光非礼了梦想. 提交于 2021-02-17 15:14:59
问题 I'm doing an api request uploading an image with var request = new http.MultipartRequest("POST", uri); var response = await request.send() in dart using flutter. I can then check the response code with for instance if (response.statusCode == 200) { print('ok'); } with other calls I can also get the response body with var result = response.body; however when using request.send() I can't seem to find out how to get the response body result. Any help or input is very much appreciated, thanks!

How to get response body with request.send() in dart

由 老子叫甜甜 提交于 2021-02-17 15:13:37
问题 I'm doing an api request uploading an image with var request = new http.MultipartRequest("POST", uri); var response = await request.send() in dart using flutter. I can then check the response code with for instance if (response.statusCode == 200) { print('ok'); } with other calls I can also get the response body with var result = response.body; however when using request.send() I can't seem to find out how to get the response body result. Any help or input is very much appreciated, thanks!
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