Flutter 实战记录

_tabController = new TabController(
    length: 3, vsync: this, initialIndex: currentTabIndex);
_tabController.addListener(() {
	// 解决TabController多次回调问题
  if (_tabController.index == _tabController.animation.value) {
      // do somethings
      //currentTabIndex = _tabController.index;
    }
  }
});

/// 解决中英文自动换行
extension FixAutoLines on String {
  String fixAutoLines() {
    return Characters(this).join('\u{200B}');
  }
}

handleMsg(arguments) {
    // 切换看板-隐藏返回箭头
    setState(() {
      isShowOverlay = false;
    });

    Map changeParam = Map%3CString, dynamic%3E.from(arguments ?? Map);

    ///默认来源mainActivity，非mainActivity来源一定传这个参数，区分来源，否则页面和数据都会有问题
    if (widget.pageKey == changeParam[AppConstant.PAGE_KEY]) {
      hardCoveTipInfo = null;
      param.clear();
      changeParam.forEach((key, value) {
        if (TextUtils.isNotEmpty(value) && AppConstant.PAGE_KEY != key) {
          param[key] = value;
        }
      });
      if (param[AppConstant.CHANNELTYPE] == AppConstant.C4) {
        // 处理 C4看板
      } else {
        // 处理 C5  C6看板
        
      }
    }
  }

jumpC4Board() {
    Map<String, dynamic> localParam = Map.castFrom(widget.param);
    localParam["fromC4C5Board"] = "1";// 解决C4看板航道选择器和 返回 C5C6 页面刷新问题
    localParam["pageKey"] = UniqueKey().toString();
    FlutterBoost.singleton
      .open(AnalysisRouteApi.nativeAnalysisHome, urlParams: localParam);
  }

List<int> imageData = await asset.originBytes;
MultipartFile multipartFile = new MultipartFile.fromBytes(
  imageData,
  filename: "asset.jpg",
  contentType: MediaType("image", "jpg"),
);

class HeicToJPGPlugin {
  static const String _channel = "com.xxxx/heicConvertJpg";

  static const String _methodConvertJpg= "convertToJPG";

  static const _perform = const MethodChannel(_channel);

  static Future<String> convertToJPG(String path) {
    return _perform.invokeMethod(_methodConvertJpg, {"heicPath": path});
  }
}



bool isHeic = false;
List<int> heicData;
if (asset.title.contains(".HEIC")) {
  isHeic = true;
  File assetFile =await asset.originFile;
  String jpgPath = await HeicToJPGPlugin.convertToJPG(assetFile.path); // JPG String formate
  File jpgFile = File(jpgPath);// JPG File formate
  final Uint8List byteData = await jpgFile.readAsBytes(); // JPG data formate: Uint8List
  heicData = List.from(byteData); // jpg data formate: List<int>
}
List<int> imageData = await asset.originBytes;

File assetFile =await asset.originFile;
List<int> imageData = await asset.thumbDataWithSize(asset.size.width.toInt(), asset.size.height.toInt(),quality:await getCompressRate(assetFile.path));

if (imageData != null) {
  MultipartFile multipartFile = new MultipartFile.fromBytes(
    imageData,
    filename: "asset.jpg",
    contentType: MediaType("image", "jpg"),
  );
}

Pointer<Uint8> pointer = Pointer<Uint8>.fromAddress(handle);
//handle 是 Native 端中一张图像的内存地址
Uint8List pixels = pointer.asTypedList(length);
ui.PixelFormat pixelFormat = Platform.isAndroid ? ui.PixelFormat.
rgba8888 : ui.PixelFormat.bgra8888;
ui.decodeImageFromPixels(pixels, width, height, pixelFormat,
(ui.Image image) {
//这个回调里的 image 对象是 Flutter 可以使用的 image 对象
}, rowBytes: rowBytes);

import 'dart:typed_data';
File assetFile =await asset.originFile;
// JPG Path
String jpgPath = await HeicToJPGPlugin.convertToJPG(assetFile.path); 
// JPG File 
File jpgFile = File(jpgPath);
// JPG Uint8List 
final Uint8List byteData = await jpgFile.readAsBytes(); 
// JPG List<int>
List<int> heicData = List.from(byteData); // jpg data formate: List<int>

List<int> compressedImageData =  await asset.thumbDataWithSize(asset.size.width.toInt(), asset.size.height.toInt(), quality: 80 );

/// Register a closure to be called when the object changes.
  ///
  /// If the given closure is already registered, an additional instance is
  /// added, and must be removed the same number of times it is added before it
  /// will stop being called.
  ///
  /// This method must not be called after [dispose] has been called.
  ///
  /// {@template flutter.foundation.ChangeNotifier.addListener}
  /// If a listener is added twice, and is removed once during an iteration
  /// (e.g. in response to a notification), it will still be called again. If,
  /// on the other hand, it is removed as many times as it was registered, then
  /// it will no longer be called. This odd behavior is the result of the
  /// [ChangeNotifier] not being able to determine which listener is being
  /// removed, since they are identical, therefore it will conservatively still
  /// call all the listeners when it knows that any are still registered.
  ///
  /// This surprising behavior can be unexpectedly observed when registering a
  /// listener on two separate objects which are both forwarding all
  /// registrations to a common upstream object.
  /// {@endtemplate}
  ///
  /// See also:
  ///
  ///  * [removeListener], which removes a previously registered closure from
  ///    the list of closures that are notified when the object changes.
  @override
  void addListener(VoidCallback listener) {
    assert(_debugAssertNotDisposed());
    _listeners!.add(_ListenerEntry(listener));
  }

/// An animation whose value represents the current position of the [TabBar]'s
  /// selected tab indicator as well as the scrollOffsets of the [TabBar]
  /// and [TabBarView].
  ///
  /// The animation's value ranges from 0.0 to [length] - 1.0. After the
  /// selected tab is changed, the animation's value equals [index]. The
  /// animation's value can be [offset] by +/- 1.0 to reflect [TabBarView]
  /// drag scrolling.
  ///
  /// If this [TabController] was disposed, then return null.
  Animation<double>? get animation => _animationController?.view;
  AnimationController? _animationController;
```>)

Column(
    mainAxisAlignment: MainAxisAlignment.start,
    crossAxisAlignment: CrossAxisAlignment.start,
    children: [
      Expanded(
        child: Text(
          result!.trackName!,
          style:
              TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
          maxLines: 2,
        ),
      ),
      SizedBox(
        height: 10,
      ),
      Text(
        result!.artistName!,
        style: TextStyle(fontSize: 12, fontWeight: FontWeight.bold),
      ),
    ],
  )

Expanded(
  child: Container(
    height: 80,
    child: Column(
      mainAxisAlignment: MainAxisAlignment.start,
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Expanded(
          child: Text(
            result!.trackName!,
            style:
                TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
            maxLines: 2,
          ),
        ),
        SizedBox(
          height: 10,
        ),
        Text(
          result!.artistName!,
          style: TextStyle(fontSize: 12, fontWeight: FontWeight.bold),
        ),
      ],
    ),
  ),
)

ClipRRect(
    borderRadius: BorderRadius.circular(15),
    child: Image.network(
      result!.artworkUrl100.toString(),
      width: 60,
      height: 60,
    ),
  )