string indices must be integers报错

                with open('shuju.json', 'r', encoding='utf-8') as rfile:
                        self.student = rfile.readlines()
                        aaa=self.id.get()
                        for dict_temp in self.student:
                            if aaa != ['']:
                                if  aaa == dict_temp['ID']:
                                    student_chaxun = dict()
                                    student_chaxun['id'] = dict_temp['ID']
                                    student_chaxun['name'] = dict_temp['name']
                                    student_chaxun['math'] = dict_temp['math']
                                    student_chaxun['chinese'] = dict_temp['chinese']
                                    student_chaxun['english'] = dict_temp['english']

line 81, in search
if aaa == dict_temp['ID']:
TypeError: string indices must be integers