If I’m in pretrial for misdemeanor theft, doI have to informmy new employer if they ask ifI have ever been convicted of a crime?

Generally, an employer in CA cannot inquire as to an applicant's arrest record unless it has to do with pending charges.

The CA labor code (CLC Sec. 432.7)states in part that:

(a) No employer, whether a public agency or private individual or corporation, shall ask an applicant for employment to disclose, through any written form or verbally, information concerning an arrest or detention that did not result in conviction, or information concerning a referral to, and participation in, any pretrial or posttrial diversion program, nor shall any employer seek from any source whatsoever, or utilize, as a factor in determining any condition of employment including hiring, promotion, termination, or any apprenticeship training program or any other training program leading to employment, any record of arrest or detention that did not result in conviction, or any record regarding a referral to, and participation in, any pretrial or posttrial diversion program. As used in this section, a conviction shall include a plea, verdict, or finding of guilt regardless of whether sentence is imposed by the court. Nothing in this section shall prevent an employer from asking an employee or applicant for employment about an arrest for which the employee or applicant is out on bail or on his or her own recognizance pending trial.