public int evaluate(String expr) {
if (expr.equalsIgnoreCase("")) {
return EMPTY;
}
entity.setFormula(mTokenizer.getLocalizedExpression(expr));
expr = mTokenizer.getNormalizedExpression(expr);
while (expr.length() > 0 && ".+-/*".indexOf(expr.charAt(expr.length() - 1)) != -1) {
expr = expr.substring(0, expr.length() - 1);
}
try {
double result = mSymbols.eval(expr);
if (Double.isNaN(result)) {
return NAN; // "NaN";
} else {
entity.setResult(
mTokenizer.getLocalizedExpression(
Util.doubleToString(result, MAX_DIGITS, ROUNDING_DIGITS)));
return RESULT; // "result";
}
} catch (SyntaxException e) {
return SYNTAX; // "syntax";
}
}
public void evaluate(String expr, EvaluateCallback callback) {
expr = mTokenizer.getNormalizedExpression(expr);
// remove any trailing operators删除任何尾随操作符
while (expr.length() > 0 && "+-/*".indexOf(expr.charAt(expr.length() - 1)) != -1) {
expr = expr.substring(0, expr.length() - 1);
}
try {
if (expr.length() == 0 || Double.valueOf(expr) != null) {
callback.onEvaluate(expr, null, Calculator.INVALID_RES_ID);
return;
}
} catch (NumberFormatException e) {
// expr is not a simple number他不是一个简单的数字
}
try {
Log.e("exprout", expr);
Double DouResult = mSymbols.eval(expr);
Log.e("exprout", "double结果为" + DouResult.toString());
// BigDecimal result = new BigDecimal(mSymbols.eval(expr));
// BigDecimal result = mExpress.calcuThisExpression(expr);
// Object objResult = i.eval(expr);
// TODO 警告！！！expr在这里还是计算式的String，还没有转换为单个数值
// Double.isInfinite(x)判断无穷大
if (DouResult.isNaN(DouResult)) {
callback.onEvaluate(expr, null, R.string.error_nan);
Log.e("exprout", "DouResult isNaN");
} else {
// The arity library uses floating point arithmetic when evaluating the expression
// leading to precision errors in the result. The method doubleToString hides these
// errors; rounding the result by dropping N digits of precision.
// 数库使用浮点运算时，计算表达式
// 导致精度误差的结果。方法double to string隐藏这些
// 误差；通过对精度下降的数字计算。
// String BigString = result.toString();
String BigString;
if (DouResult.isInfinite()) {
BigString = "Infinity";
} else if (expr.matches("[.\\d()\\+\\-\\*\\/]*")) {
try {
Expression mExpress = new Expression(expr);
BigString = mExpress.calcuCurrentExpression();
} catch (Exception e) {
callback.onEvaluate(expr, null, R.string.error_syntax);
BigDecimal result = new BigDecimal(mSymbols.eval(expr));
BigString = result.toString();
}
} else {
BigDecimal result = new BigDecimal(mSymbols.eval(expr));
BigString = result.toString();
}
Log.e("exprout", "BigDecimal结果为" + BigString);
resultString =
mTokenizer.getLocalizedExpression(
// Util.DoubleToString(result, MAX_DIGITS, ROUNDING_DIGITS));
BigString);
callback.onEvaluate(expr, resultString, Calculator.INVALID_RES_ID);
}
} catch (SyntaxException e) {
callback.onEvaluate(expr, null, R.string.error_syntax);
}
}