flutter_appfx/lib/utils/tools.dart

import 'dart:convert';
import 'dart:math';


// DateFormat('dd.MM.yy HH:mm:ss').format(dateCreated); // ??

String formatTimeStamp({int? timeStamp, DateTime? date, format='yyyy-MM-dd HH:mm:ss'}) {
  try {
    var time = (date != null) ? date
        : ((timeStamp != null) ? DateTime.fromMillisecondsSinceEpoch(timeStamp) : DateTime.now());

    var dateObj = {
      'M+': time.month, //月份
      'd+': time.day, //日
      'H+': time.hour, //小时
      'm+': time.minute, //分
      's+': time.second, //秒
    };
    RegExp yearReg = RegExp(r"(y+)");
    if (yearReg.hasMatch(format)) {
      var matches = yearReg.allMatches(format);
      String match = "${matches.elementAt(0).group(1)}";
      format = format.replaceAll(match, "${time.year}".substring(4 - match.length));
    }
    dateObj.forEach((key, value) {
      RegExp replaceReg = RegExp(r'(' + key + ')');
      if (replaceReg.hasMatch(format)) {
        var matches = replaceReg.allMatches(format);
        String match = "${matches.elementAt(0).group(1)}";
        format = format.replaceAll(match, (match.length == 1) ? "$value" : "00$value".substring("$value".length));
      }
    });
    return format;

  } catch (error) {
    return '';
  }
}


void printJsonStr(String input) {
  const JsonDecoder decoder = JsonDecoder();
  const JsonEncoder encoder = JsonEncoder.withIndent('  ');
  final dynamic object = decoder.convert(input);
  final dynamic prettyString = encoder.convert(object);
  prettyString.split('\n').forEach((dynamic element) => print(element));
}

void printJson(Map input) {
  const JsonEncoder encoder = JsonEncoder.withIndent('    ');
  final dynamic prettyString = encoder.convert(input);
  prettyString.split('\n').forEach((dynamic element) => print(element));
}

// move to fileUtils.dart
// String formatFileSize(int size) {
//   final fileSizeInKB = size / 1000;
//   if (fileSizeInKB < 1) {
//     return '$size bytes';
//   }
//   final fileSizeInMB = fileSizeInKB / 1000;
//   if (fileSizeInMB < 1) {
//     return '${fileSizeInKB.toStringAsFixed(2)} KB';
//   }
//   final fileSizeInGB = fileSizeInMB / 1000;
//   if (fileSizeInGB < 1) {
//     return '${fileSizeInMB.toStringAsFixed(2)} MB';
//   }
//   final fileSizeInTB = fileSizeInGB / 1000;
//   if (fileSizeInTB < 1) {
//     return '${fileSizeInGB.toStringAsFixed(2)} GB';
//   }
//   return '${fileSizeInTB.toStringAsFixed(2)} TB';
// }


// 均匀分组
List<int> uniformGrouping(int totalSize, int defaultGroupSize) {
  if (totalSize < 0) {
    return [];
  } else if (totalSize == 0) {
    return [0];
  }

  final int theUpperLimit = (defaultGroupSize * 1.5).toInt(); // 折行上限
  if (totalSize <= theUpperLimit) {
    return [totalSize];
  } else if ((totalSize > theUpperLimit) && (totalSize <= (defaultGroupSize * 2))) {
    int half = totalSize ~/ 2;
    return [half, totalSize - half];
  }

  final int groupNumber = totalSize ~/ defaultGroupSize;
  final int remainder = totalSize % defaultGroupSize;
  List<int> group = [];
  if (remainder == 0) {
    for (int i = 0; i < groupNumber; i++) {
      group.add(defaultGroupSize);
    }
  } else {
    final splitRemainder = remainder ~/ groupNumber;
    final groupRemainder = remainder % groupNumber;
    for (int i = 0; i < groupRemainder; i++) {
      group.add(defaultGroupSize + splitRemainder + 1);
    }
    for (int i = groupRemainder; i < groupNumber; i++) {
      group.add((defaultGroupSize + splitRemainder));
    }
  }

  return group;
}


String ellipsizeStrMiddle(String str, {
  int headerLen = 4,
  int tailLen = 4,
  String splitter = '...',
}) {
  if (str.length > 2) {
    int liveHeaderLen = headerLen;
    int liveTailLen = tailLen;
    int loopN = min(liveHeaderLen, liveTailLen);
    for (int i = 0; i < loopN; i++) {
      if (str.length > (liveHeaderLen + liveTailLen)) {
        String prefix = str.substring(0, liveHeaderLen);
        String suffix = str.substring(str.length - liveTailLen);
        return '$prefix$splitter$suffix';
      }
      liveHeaderLen--;
      liveTailLen--;
    }
    String prefix = str.substring(0, liveHeaderLen);
    String suffix = str.substring(str.length - liveTailLen);
    return '$prefix$splitter$suffix';
  } else {
    return str;
  }
}