iphone pickerview 两列例子

#import
//定义两个常量，用来表示2个组件
#define PickerOne 0
#define PickerTwo 1
//添加UIPickerView的委托方法和数据源方法
@interface DoublePickerViewViewController : UIViewController
{
//定义输出口，字典，数组
UIPickerView *picker;
NSDictionary *zidian;
NSArray *city;
NSArray *zips;
}
@property (nonatomic ,retain) IBOutlet UIPickerView *picker;
@property (nonatomic ,retain) NSDictionary *zidian;
@property (nonatomic ,retain) NSArray *city;
@property (nonatomic ,retain) NSArray *zips;
//定义按钮点击时候触发的代码
- (IBAction) buttonPressed:(id)sender;
@end

复制代码

.m文件

#import "DoublePickerViewViewController.h"
@implementation DoublePickerViewViewController
@synthesize picker;
@synthesize zidian;
@synthesize city;
@synthesize zips;
//按钮触发代码
- (IBAction) buttonPressed:(id)sender
{
//询问选取器选中了哪个行
NSInteger cityRow = [picker selectedRowInComponent:PickerOne];
NSInteger zipsRow = [picker selectedRowInComponent:PickerTwo];
//返回选中行的值
NSString *cityName = [self.city objectAtIndex:cityRow];
NSString *zipsName = [self.zips objectAtIndex:zipsRow];
//把选中的值分配给字符串
NSString *title = [[NSString alloc] initWithFormat:@"你选择的邮编是%@",zipsName];
NSString *message = [[NSString alloc] initWithFormat:@"%@是在%@里的邮编",
zipsName,cityName];
//定义一个警告窗口
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:title
cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
[alert release];
[title release];
[message release];
}
- (void)viewDidLoad
{
//提取对应用程序主束的引用，主要是为了获取添加在Resources的资源
NSBundle *bundle = [NSBundle mainBundle];
//获取code.plist的路径
NSString *listPath = [bundle pathForResource:@"code" ofType:@"plist"];
//用获取到的路径创建一个字典文件
NSDictionary *dictionary = [[NSDictionary alloc] initWithContentsOfFile:listPath];
//分配给zidian
self.zidian = dictionary;
[dictionary release];
//获取字典里所有的数组
NSArray *components = [self.zidian allKeys];
//按照字母顺序排序
NSArray *sorted = [components sortedArrayUsingSelector:@selector(compare:)];
//然后分配给city
self.city = sorted;
//提取索引为0的city行，也就是第一行
NSString *selectedCity = [self.city objectAtIndex:0];
//用这个返回的字符串提取对应的zips数组
NSArray *array = [zidian objectForKey:selectedCity];
//将它分配给zips
self.zips = array;
[super viewDidLoad];
}
- (void)viewDidUnload
{
self.picker = nil;
self.zidian = nil;
self.city = nil;
self.zips = nil;
[super viewDidUnload];
}
- (void)dealloc {
[picker release];
[zidian release];
[city release];
[zips release];
[super dealloc];
}
#pragma mark -
#pragma mark picker 数据源方法
//选取器如果有多个滚轮，就返回滚轮的数量，我们这里有两个，就返回2
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 2;
}
//返回给定的组件有多少行数据，我们有2个组件，所以用if操作。后期tableview也是类似的操作方法
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
if (component == PickerOne) {
return [self.city count];
}
return [self.zips count];
}
#pragma mark -
#pragma mark picker 委托方法
//官方的意思是，指定组件中的指定数据，我理解的就是目前选中的是哪一行。
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row
forComponent:(NSInteger)component
{
if (component == PickerOne) {
return [self.city objectAtIndex:row];
}
return [self.zips objectAtIndex:row];
}
//当选取器的行发生改变的时候调用这个方法
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row
inComponent:(NSInteger)component
{
//如果第一个滚轮发生改变，开始一下方法。
if (component == PickerOne) {
//选中了哪个城市
NSString *selectedCity = [self.city objectAtIndex:row];
//在字典里找到对应的邮编
NSArray *array = [zidian objectForKey:selectedCity];
//分配给zips
self.zips = array;
//右侧的邮编，默认停留在第一行，0表示第一行。
[picker selectRow:0 inComponent:PickerTwo animated:YES];
//重新加载第二个滚轮。
[picker reloadComponent:PickerTwo];
}
}
@end