关于多标签视图的问题

Question

界面如下图当我点击第二个标签 single的时候，界面就直接跳出来了，直接调到模拟器的主界面了，怎么回事？那个标签页的.h代码：如下
#import <UIKit/UIKit.h>
@interface SingleComponentPickerViewController : UIViewController
<UIPickerViewDelegate,UIPickerViewDataSource>
{
IBOutlet UIPickerView  *singlepicker;
NSArray *pickerdate;
}
@property (nonatomic,retain) UIPickerView *singlepicker;
@property (nonatomic,retain) NSArray *pickerdate;-(IBAction)buttonpressed;@end
标签页 .m 代码
#import "SingleComponentPickerViewController.h"
@implementation SingleComponentPickerViewController
@synthesize singlepicker;
@synthesize  pickerdate;// The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
/*
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization.
    }
    return self;
}
*//*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/-(IBAction)buttonpressed
{
NSInteger row=[singlepicker selectedRowInComponent:0];//select the frist singlepicker
NSString *select=[pickerdate objectAtIndex:row];
NSString *title=[[NSString alloc]initWithFormat:@"you select %@",select];
UIAlertView *alert=[[UIAlertView alloc]initWithTitle:title
message:@"thanks you for choosing"
delegate:nil
   cancelButtonTitle:@"you are welcome" 
   otherButtonTitles:nil];
[alert show];
[alert release];
[title release];
}// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
NSArray *array=[[NSArray alloc] initWithObjects:@"Luke",@"Leia",@"Han",@"Chewbacca",@"Artoo",@"Threepio",@"Lando",nil];
self.pickerdate=array;
[array release];
    [super viewDidLoad];
}
/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations.
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
    
    // Release any cached data, images, etc. that aren't in use.
}- (void)viewDidUnload {

    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}
- (void)dealloc {
[singlepicker release];
[pickerdate release];
    [super dealloc];
}#pragma  -
#pragma  Picker Data Source Methods
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 1;
}-(NSInteger)pickerView:(UIPickerView*)pickerView numberOfRowInComponent:(NSInteger)component
{
return [pickerdate count];
}
#pragma  Picker delegate Methods
-(NSString*) pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
return [pickerdate objectAtIndex:row];
}@end