颤振 无法解码图像.提供的图像必须是位图，空)

Question

在颤振的谷歌地图中创建自定义图标显示错误。

我的pubspec.yaml文件

assets:
- assets/truck.png

我的代码是：

void getCustomIcon() async {
customIcon = await BitmapDescriptor.fromAssetImage(
ImageConfiguration(
devicePixelRatio: 2.5,
),
'assets/truck.png');
}

错误是：

[ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: PlatformException(error, Failed to decode image. The provided image must be a Bitmap., null)
E/flutter (15757): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:569:7)
E/flutter (15757): #1      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:321:33)

Answer 1

在状态类中定义

BitmapDescriptor customIcon ;

initState呼入

getBytesFromAsset('assets/truck.png', 64).then((onValue) {
customIcon =BitmapDescriptor.fromBytes(onValue);
});

其中函数是

static Future<Uint8List> getBytesFromAsset(String path, int width) async {
ByteData data = await rootBundle.load(path);
ui.Codec codec = await ui.instantiateImageCodec(data.buffer.asUint8List(), targetWidth: width);
ui.FrameInfo fi = await codec.getNextFrame();
return (await fi.image.toByteData(format: ui.ImageByteFormat.png)).buffer.asUint8List();
}

然后在标记创建中

markers.add(
Marker(
markerId: ....,
position: ....,
icon: customIcon ,
onTap: () { 
....
}
)
);