ado666
this._image.width < (this._tilewidth + this._spacing)且this._image.height < (this._tileheight + this._margin)的时候this._lastgid < this._firstgid，会导致contains里面的判断问题
add null safty support, flutter sdk upgraded to 2.15.1
> : Error: 'AssetManifest' is imported from both 'package:flutter/src/services/asset_manifest.dart' and 'package:google_fonts/src/asset_manifest.dart'. > google_fonts_base.dart:14 > import 'asset_manifest.dart'; > ^^^^^^^^^^^^^ > > : Error: 'AssetManifest' is imported from both 'package:flutter/src/services/asset_manifest.dart' and 'package:google_fonts/src/asset_manifest.dart'....