ios5应用实现下拉列表 dropDownList=[[DropDownList alloc]initWithFrame:CGRectMake(20, 20, 80, 30)]; NSArray *comboBoxDatasource = [[NSArray alloc] initWithObjects:@"one", @"two", @"three", @"four", @"five", @"six", @"seven", @"eight", nil]; dropDownList.list=comboBoxDatasource; [self.view addSubvi