flutter 笔记

1. RefreshIndicator不能下拉刷新

• list高度不够不能下拉刷新
• 解决：list属性中添加physics: new AlwaysScrollableScrollPhysics()

2. chewie播放视蒙层过暗, 背景图片在横屏时候会溢出

一步一步找源码,找到播放控制代码

import 'package:chewie/src/player_with_controls.dart';
Widget _buildPlayerWithControls(
      ChewieController chewieController,
      BuildContext context,
    ) {
      return Stack(
        children: <Widget>[
          // if (chewieController.placeholder != null)
            // chewieController.placeholder!,
          if (chewieController.placeholder != null &&
              !chewieController.isFullScreen) // 横屏时候不显示背景
            chewieController.placeholder!,
          Center(
            child: AspectRatio(
              aspectRatio: chewieController.aspectRatio ??
                  chewieController.videoPlayerController.value.aspectRatio,
              child: VideoPlayer(chewieController.videoPlayerController),
            ),
          ),
          if (chewieController.overlay != null) chewieController.overlay!,
          if (Theme.of(context).platform != TargetPlatform.iOS)
            Consumer<PlayerNotifier>(
              builder: (
                BuildContext context,
                PlayerNotifier notifier,
                Widget? widget,
              ) =>
                  AnimatedOpacity(
                opacity: notifier.hideStuff ? 0.0 : 0.8,
                duration: const Duration(
                  milliseconds: 250,
                ),
                child: Container(
                  decoration: const BoxDecoration(color: Colors.transparent), // 蒙层背景颜色设置成透明
                  child: Container(),
                ),
              ),
            ),
          if (!chewieController.isFullScreen)
            _buildControls(context, chewieController)
          else
            SafeArea(
              bottom: false,
              child: _buildControls(context, chewieController),
            ),
        ],
      );
    }

3. stack中使用Column

• 要包裹一层ConstrainedBox

      ConstrainedBox(
        constraints: BoxConstraints(
          maxWidth: Adapt.screenW() - 20,
        ),
        child: Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
          
        ]));

4. 键盘弹出影响布局 - 注意修改所有的scaffold

Scaffold(
        resizeToAvoidBottomInset: false,
)

5. 子StatefulWidget中更新状态setState子组件不更新

• 变量命名为内部变量_items再更新列表，子组件就实现更新了

6. 页面滚动到对应位置

给对应元素设置一个key - mKey,之后Scrollable.ensureVisible

Scrollable.ensureVisible(mKey.currentContext);

tips: 感觉和前端描点差不多的意思

7. BackButton 安卓返回是一个箭头，直接修改源码

class BackButtonIcon extends StatelessWidget {
  /// Creates an icon that shows the appropriate "back" image for
  /// the current platform (as obtained from the [Theme]).
  const BackButtonIcon({Key? key}) : super(key: key);

  /// Returns the appropriate "back" icon for the given `platform`.
  static IconData _getIconData(TargetPlatform platform) {
    switch (platform) {
      case TargetPlatform.android:
      case TargetPlatform.fuchsia:
      case TargetPlatform.linux:
      case TargetPlatform.windows:
        return Icons.arrow_back_ios; // 全部改为arrow_back_ios
      case TargetPlatform.iOS:
      case TargetPlatform.macOS:
        return Icons.arrow_back_ios;
    }
  }

  @override
  Widget build(BuildContext context) =>
      Icon(_getIconData(Theme.of(context).platform));
}