UIPickerView和UIDatePicker是类似的控件，只不过UIDatePicker是日期控件，只能放日期，而UIPickerView可以放任何东西。

UIPickerView高度固定，设置无效。

使用前时要添加代理

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate,UIPickerViewDelegate,UIPickerViewDataSource>

{

    UIPickerView *picker;

}

@property (strong, nonatomic) UIWindow *window;

@end

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];    // Override point for customization after application launch.    self.window.backgroundColor = [UIColor whiteColor];    [self.window makeKeyAndVisible];        picker  =[[UIPickerView alloc]initWithFrame:CGRectMake(0, 50, 200, 0) ];    picker.delegate=self;    [self.window addSubview:picker];    return YES;}//设置UIPickerView有几个区域- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{    return 2;}//设置UIPickerView每个区域的行数- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{    if(component==0)    {        return 2;    }    else    {        return 3;    }}//设置UIPickerView现实的标题- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{    if(component==0)    {        NSArray *array=@[@"1",@"2"];        return array[row];    }    else    {        NSArray *array=@[@"1",@"2",@"3"];        return array[row];    }}//为UIPickerView设置视图，所以UIPickerView不当可以显示文字 还可以显示图片- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{    UIImageView *view1=[[UIImageView alloc]initWithImage:[UIImage imageNamed:@"apple.jpg"]];    view1.frame=CGRectMake(0, 0, 80, 40);    return view1;}//为UIPickerView设置多样化字符串- (NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component NS_AVAILABLE_IOS(6_0){    return NSAttributedString对象;}//获得UIPickerView的选择的区和行，进而获取及其内容- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{    NSLog(@"----%d--%d",row,component);}