[FTC]: [help] can't set the motorPower to zero with encoders

Other FIRST Tech Challenge
1

I want to set the power of the motor’s to zero when they reaches their target. But now they are stopping but they are still busy. And the encoders aren’t resetting.
This is my code, it’s in opMode
if (gamepad1.b) { int targetPosition = 0; motorLeft.setMode(DcMotorController.RunMode.RUN_USING_ENCODERS); motorRight.setMode(DcMotorController.RunMode.RUN_USING_ENCODERS);
motorLeft.setMode(DcMotorController.RunMode.RESET_ENCODERS);
motorRight.setMode(DcMotorController.RunMode.RESET_ENCODERS);
//while (motorLeft.getCurrentPosition() != 0){
//}
motorLeft.setTargetPosition(targetPosition);
motorRight.setTargetPosition(targetPosition);

    motorRight.setMode(DcMotorController.RunMode.RUN_TO_POSITION);
    motorLeft.setMode(DcMotorController.RunMode.RUN_TO_POSITION);
    //if (motorLeft.getCurrentPosition() != targetPosition) {
        motorLeft.setPower(-0.5);
        motorRight.setPower(-0.5);
    //}
    //motorLeft.setPower(0);
    //motorRight.setPower(0);

}