Flutter-打印获取文件行号扩展

使用案例

"参数:${settings.arguments}".log(); // 普通文本输出
null.log(); // 对象输出

打印输出内容

普通文本输出结果
flutter: 
=========================开始===========================
文件: main.dart -> 55行 
内容: 参数:null
=========================结束===========================
对象输出结果
flutter: 
=========================开始===========================
文件: main.dart -> 56行 
内容: null
=========================结束===========================

源码

extension StringExtension on String {
  /// 打印
  void log() {
    CustomTrace info = CustomTrace(StackTrace.current);
    if (info != null &&
        info.fileName != null &&
        info.lineNumber != null) {
      print(
          "\n=========================开始===========================\n文件: ${info.fileName} -> ${info.lineNumber}行 \n内容: $this\n=========================结束===========================");
    } else {
      print("\n=========================开始===========================\n内容: $this\n=========================结束===========================");
    }
  }
}

extension ObjectExtension on Object {
  void lod() {
    String string = this.toString();
    string.log();
  }
}

class CustomTrace {
  final StackTrace _trace;
  String fileName;
  int lineNumber;
  int columnNumber;

  CustomTrace(this._trace) {
    _parseTrace();
  }

  void _parseTrace() {
    var list = this._trace.toString().split("\n");
    var traceString = list.first;
    if (list.length > 1) traceString = list[1];
    var indexOfFileName = traceString.indexOf(RegExp(r'[A-Za-z_]+.dart'));
    var fileInfo = traceString.substring(indexOfFileName);
    var listOfInfos = fileInfo.split(":");
    this.fileName = listOfInfos[0];
    this.lineNumber = int.parse(listOfInfos[1]);
    var columnStr = listOfInfos[2];
    columnStr = columnStr.replaceFirst(")", "");
    this.columnNumber = int.parse(columnStr);
  }
}

踩坑(因为刚学Flutter 代码啥的都是百度的)

因为是扩展越简单越方便 怎么简单怎么来 那么我们想获取的信息可能会存在异常 如下:
从使用上来说 每次都需要携带StackTrace.current堆栈信息是比较麻烦的所以我将其写在了方法内部 但是问题来了 这样获取的最前面一个信息是当前的扩展信息

CustomTrace info = CustomTrace(StackTrace.current);

百度方法打印

void _parseTrace() {
    var list = this._trace.toString().split("\n");
    var traceString = list.first;
    var indexOfFileName = traceString.indexOf(RegExp(r'[A-Za-z_]+.dart'));
    var fileInfo = traceString.substring(indexOfFileName);
    var listOfInfos = fileInfo.split(":");
    this.fileName = listOfInfos[0];
    this.lineNumber = int.parse(listOfInfos[1]);
    var columnStr = listOfInfos[2];
    columnStr = columnStr.replaceFirst(")", "");
    this.columnNumber = int.parse(columnStr);
  }

输出一直异常 一直定位到扩展

flutter: 
=========================开始===========================
文件: extension.dart -> 9行 
内容: 参数:{}
=========================结束===========================

我们来打印信息看看

 void _parseTrace() {
    print(this._trace.toString()); // 打印信息
    ...
  }

输出结果(从以下结果可以看出最前面一个一直会是我们的扩展, 而真实想要的信息是第二个)

flutter: 
#0      StringExtension.log (package:flutter_demo/extension/extension.dart:9:47)
#1      _MyAppState.routeFactory (package:flutter_demo/main.dart:55:32)
#2      routeFactoryWrapper.<anonymous closure> (package:flutter_boost/src/boost_navigator.dart:17:29)
#3      BoostPage.create (package:flutter_boost/src/flutter_boost_app.dart:638:55)
#4      new BoostContainer (package:flutter_boost/src/boost_container.dart:14:26)
#5      FlutterBoostAppState._createContainer (package:flutter_boost/src/flutter_boost_app.dart:178:12)
#6      FlutterBoostAppState.initState (package:flutter_boost/src/flutter_boost_app.dart:91:9)
#7      StatefulElement._firstBuild (package:flutter/src/widgets/framework.dart:4723:57)
#8      ComponentElement.mount (package:flutter/src/widgets/framework.dart:4556:5)
#9      Element.inflateWidget (package:flutter/src/widgets/framework.dart:3631:14)
#10     Element.updateChild (package:flutter/src/widgets/framework.dart:3383:18)
#11     ComponentElement.performRebuil<…>

改进写法(把自己这一层排除掉OK)

void _parseTrace() {
    var list = this._trace.toString().split("\n");
    var traceString = list.first;
    if (list.length > 1) traceString = list[1]; // 有多个时去掉扩展这一层
    var indexOfFileName = traceString.indexOf(RegExp(r'[A-Za-z_]+.dart'));
    var fileInfo = traceString.substring(indexOfFileName);
    print("打印" + this._trace.toString());
    var listOfInfos = fileInfo.split(":");
    this.fileName = listOfInfos[0];
    this.lineNumber = int.parse(listOfInfos[1]);
    var columnStr = listOfInfos[2];
    columnStr = columnStr.replaceFirst(")", "");
    this.columnNumber = int.parse(columnStr);
  }

参考https://www.jianshu.com/p/54f0efc2b606