本篇实现功能是两个选取器的关联操作，滚动第一个滚轮第二个滚轮内容随着第一个的变化而变化，然后点击按钮触发一个动作；工程是在 代码实现UIPickerView 一文中基础上修改的，建工程就不多说，先把效果图贴出来:
1.首先在工程中建一个songInfo.plist文件，储存数据，
添加的内容是：
2.在ViewController定一个选取器pickerView对象，两个数组，存放选取器数据和一个字典，读取plist文件
#import <UIKit/UIKit.h> @interface ViewController : UIViewController<UIPickerViewDelegate,UIPickerViewDataSource> { //定义滑轮组建 UIPickerView *pickerView; // 储存第一个选取器的的数据 NSArray *singerData; // 储存第二个选取器 NSArray *singData; // 读取plist文件数据 NSDictionary *pickerDictionary; } -(void) buttonPressed:(id)sender; @end3.在ViewController.m文件中ViewDidLoad完成初始化
首先定义两个宏定义，分别表示两个选取器的索引序号值，放在 #import "ViewController.h"后面
#define singerPickerView 0
#define singPickerView 1
- (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 0, 320, 216)]; // 指定Delegate pickerView.delegate=self; pickerView.dataSource=self; // 显示选中框 pickerView.showsSelectionIndicator=YES; [self.view addSubview:pickerView]; // 获取mainBundle NSBundle *bundle = [NSBundle mainBundle]; // 获取songInfo.plist文件路径 NSURL *songInfo = [bundle URLForResource:@"songInfo" withExtension:@"plist"]; // 把plist文件里内容存入数组 NSDictionary *dic = [NSDictionary dictionaryWithContentsOfURL:songInfo]; pickerDictionary=dic; // 将字典里面的内容取出放到数组中 NSArray *components = [pickerDictionary allKeys]; //选取出第一个滚轮中的值 NSArray *sorted = [components sortedArrayUsingSelector:@selector(compare:)]; singerData = sorted; // 根据第一个滚轮中的值，选取第二个滚轮中的值 NSString *selectedState = [singerData objectAtIndex:0]; NSArray *array = [pickerDictionary objectForKey:selectedState]; singData=array; // 添加按钮 CGRect frame = CGRectMake(120, 250, 80, 40); UIButton *selectButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; selectButton.frame=frame; [selectButton setTitle:@"SELECT" forState:UIControlStateNormal]; [selectButton addTarget:self action:@selector(buttonPressed:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:selectButton]; } 按钮事件设置
-(void) buttonPressed:(id)sender { // 获取选取器某一行索引值 NSInteger singerrow =[pickerView selectedRowInComponent:singerPickerView]; NSInteger singrow = [pickerView selectedRowInComponent:singPickerView]; // 将singerData数组中值取出 NSString *selectedsinger = [singerData objectAtIndex:singerrow]; NSString *selectedsing = [singData objectAtIndex:singrow]; NSString *message = [[NSString alloc] initWithFormat:@"你选择了%@的%@",selectedsinger,selectedsing]; UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示" message:message delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil]; [alert show]; }4.关于两个协议的代理方法
#pragma mark - #pragma mark Picker Date Source Methods //返回显示的列数 -(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView { // 返回几就有几个选取器 return 2; } //返回当前列显示的行数 -(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component { if (component==singerPickerView) { return [singerData count]; } return [singData count]; }#pragma mark Picker Delegate Methods //返回当前行的内容,此处是将数组中数值添加到滚动的那个显示栏上 -(NSString*)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component { if (component==singerPickerView) { return [singerData objectAtIndex:row]; } return [singData objectAtIndex:row]; }-(void)pickerView:(UIPickerView *)pickerViewt didSelectRow:(NSInteger)row inComponent:(NSInteger)component { // 如果选取的是第一个选取器 if (component == singerPickerView) { // 得到第一个选取器的当前行 NSString *selectedState =[singerData objectAtIndex:row]; // 根据从pickerDictionary字典中取出的值，选择对应第二个中的值 NSArray *array = [pickerDictionary objectForKey:selectedState]; singData=array; [pickerView selectRow:0 inComponent:singPickerView animated:YES]; // 重新装载第二个滚轮中的值 [pickerView reloadComponent:singPickerView]; } }//设置滚轮的宽度 -(CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component { if (component == singerPickerView) { return 120; } return 200; } 在这个方法中，-(void)pickerView:(UIPickerView *)pickerViewt didSelectRow:(NSInteger)row inComponent:(NSInteger)component ，我把(UIPickerView *)pickerView参数改成了(UIPickerView *)pickerViewt，因为我定义的pickerView对象和参数发生冲突，所以把参数给改了下；
附上源代码:http://download.csdn.net/detail/duxinfeng2010/4414456
