十六进制带符号（-号）

蓝牙与硬件交互的项目，遇到这样需要求，蓝牙返回的数据，带有符号 （-号）

IMG_2DF2626A 7035-1.jpeg

• (NSString *)decimalwithFormat:(NSData *)dataV {

  if (dataV == nil) {
  return @"0";
  }

  NSData *ff = [DataConvert hexStringToData:@"FFFFFFFF"];
  NSInteger addupInt;
  NSString *resultStr;
  float addupF = 0.00;

  if ([[dataV subdataWithRange:NSMakeRange(0, 1)] isEqualToData:[DataConvert hexStringToData:@"ff"]]) {

    addupInt = [DataConvert dataToInteger:ff] - [DataConvert dataToInteger:dataV];
    addupF = (addupInt + 1) * 0.01;
    resultStr = [NSString stringWithFormat:@"-%.2f",addupF];
  

  } else {
  addupInt = [DataConvert dataToInteger:dataV];
  addupF = addupInt * 0.01;
  resultStr = [NSString stringWithFormat:@"%.2f",addupF];
  }

  NSLog(@"格式化数据 -- %@",resultStr);
  return resultStr;
  }