UIPicker实现循环联动效果

用UIPicker实现循环联动效果：

效果图：

具体步骤：

1.新建一个Empty Project，添加一个rootViewController；

2.DXWAppDelegate.h:

#import <UIKit/UIKit.h>
@class rootViewController;
@interface DXWAppDelegate :UIResponder <UIApplicationDelegate>
@property (strong,  nonatomic) UIWindow *window;
@property(nonatomic,strong)rootViewController * rootVController;
@end
 

DXWAppDelegate.m:
#import "DXWAppDelegate.h"
#import "rootViewController.h"
@implementation

- (void)dealloc
{
_window release];
    [_rootVController  release];
super dealloc];
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary
{
    self.window = [[[UIWindowalloc] initWithFrame:[[UIScreenmainScreen] bounds]] autorelease];
    self.rootVController = [[rootViewControlleralloc] initWithNibName:@"rootViewController"bundle:nil];
    self.window.rootViewController =self.rootVController;
    self.window.backgroundColor = [UIColorwhiteColor];
    [self.windowmakeKeyAndVisible];
    return YES;
}
 3. 
rootViewController.h: 
#import <UIKit/UIKit.h>
@interface rootViewController :UIViewController<UIPickerViewDelegate,UIPickerViewDataSource>
@property (retain,  nonatomic) IBOutlet UIPickerView *picker;
@property(retain,nonatomic)NSArray *arrChinese;
@property(retain,nonatomic)NSArray *arrPY;
@end
 

rootViewController.m:
#import "rootViewController.h"
#define component_0 0
#define other_component  1
#define max 16384
@interfacerootViewController ()

@end

@implementation

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle
{
self = [superinitWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
        // Custom initialization
    }
    returnself;
}

- (void)viewDidLoad
{
    [superviewDidLoad];
    NSArray *array = [NSArrayarrayWithObjects:@"上海",@"北京",@"天津",@"四川",@"台湾",@"香港",@"江苏",@"湖北",@"山东",@"浙江",nil];
self.arrChinese
    array = [NSArrayarrayWithObjects:@"shanghai",@"beijing",@"tianjin",@"sichuan",@"taiwai",@"xianggang",@"jiangsu",@"hubei",@"shandong",@"zhejiang",nil];
self.arrPY
    //用来设置默认选项
    [self.pickerselectRow:max/2inComponent:component_0animated:YES];
    [self.pickerselectRow:max/2inComponent:other_componentanimated:YES];
}

//每个组件有几行数据
-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    //创建数据
if(component ==component_0)
    {
        //return [self.arrChinese count];   //动态获取数字
return  max;
else{
        //return [self.arrPY count];
return  max;
    }
}

#pragma mark delegate
//每个组件的每行显示什么数据
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
if(component ==component_0)
    {
return [self.arrChineseobjectAtIndex:row%([self.arrChinesecount])];
else{
return [self.arrPYobjectAtIndex:row%[self.arrPYcount]];
    }
}

//设置几个Component
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView
{
return  2;
}

//当你对一个pickerView进行了一次操作之后都会被调用
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
NSString *str =nil;
if(component ==component_0)
    {
NSLog(@"%i",row);
        [self.pickerselectRow:row inComponent:other_componentanimated:YES];
    }
else
    {
NSLog(@"%i",row);
//        str = [self.arrPY objectAtIndex:row];
        [self.pickerselectRow:row inComponent:component_0animated:YES];
    }
}

- (void)dealloc {
_picker  release];
    [_arrChineserelease];
_arrPY  release];
super  dealloc];
}
@end

注意：在使用picker之前要右击控件到File's owner，将delegate和datasource绑定到File''s owner中