I'm making a calculator in Android Studio and am facing a problem.
Here is my code:
String input = getinput();
try {
if (!isEmpty() && !stateError) {
if (input.contains("x")){
input.replaceAll("x","*");
}
Expression expression = new ExpressionBuilder(input).build();
}
} catch (Exception e) { }
When I type Expression
, it shows the error:
"Cannot resolve symbol 'Expression'."
Is there any solution to solve this problem?
I don't know if you have found this or not, but there is this site that I found that seems to be the API for Expression
and ExpressionBuilder
called exp4j.
If that is in fact the API, then this is the download link for it.
Another way to evaluate an equation from a String
in Java is to use the ScriptEngine interface along with the ScriptEngineManager class. You can use it like the following:
ScriptEngineManager mgr = new ScriptEngineManager();
ScriptEngine engine = mgr.getEngineByName("javascript");
try {
String result = engine.eval(stringEquation).toString();
System.out.println("Result: "+result);
}
catch (ScriptException se) {
// Handle error
}
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