Fix reflecting issue for TransferContract after json unmarshaling (#81)

* Fix reflecting issue for TransferContract after json unmarshaling

* Change type conversion from []interface{} to []string

pkg/abi/abi.go

@@ -130,16 +130,19 @@ func GetPaddedParam(param []Param) ([]byte, error) {
 				}
 
 				if (ty.Elem.T == eABI.IntTy || ty.Elem.T == eABI.UintTy) &&
-					ty.Elem.Size > 64 &&
-					reflect.TypeOf(v).Elem().Kind() == reflect.String {
+					ty.Elem.Size > 64 {
 					tmp := make([]*big.Int, 0)
-					for _, s := range v.([]string) {
+					tmpSlice, ok := v.([]string)
+					if !ok {
+						return nil, fmt.Errorf("unable to convert array of unints %+v", p)
+					}
+					for i := range tmpSlice {
 						var value *big.Int
 						// check for hex char
-						if strings.HasPrefix(s, "0x") {
-							value, _ = new(big.Int).SetString(s[2:], 16)
+						if strings.HasPrefix(tmpSlice[i], "0x") {
+							value, _ = new(big.Int).SetString(tmpSlice[i][2:], 16)
 						} else {
-							value, _ = new(big.Int).SetString(s, 10)
+							value, _ = new(big.Int).SetString(tmpSlice[i], 10)
 						}
 						tmp = append(tmp, value)
 					}