UIWebview的前進，然後向後並不總是工作

Question

我用下面的代碼進行Webview導航。

下面的代碼運行良好某些URL，但它不工作的一些網址..我不知道我在我的代碼沒有錯誤...

.H

#import <UIKit/UIKit.h> 

@interface WebviewViewController : UIViewController <UIWebViewDelegate> 
{ 
    IBOutlet UIWebView * webview; 
    IBOutlet UIToolbar * tBar; 
    IBOutlet UIBarButtonItem * backbtn; 
    IBOutlet UIBarButtonItem * forwardbtn; 
} 
@property (nonatomic, retain) IBOutlet UIWebView * webview; 
@property (nonatomic, retain) IBOutlet UIBarButtonItem * backbtn; 
@property (nonatomic, retain) IBOutlet UIBarButtonItem * forwardbtn; 
@property (nonatomic, retain) UIToolbar * tBar; 
- (IBAction)goBackbttn:(id)sender; 
- (IBAction)goForwardbttn:(id)sender; 
@end 

.M

#import "WebviewViewController.h" 
@implementation WebviewViewController 
@synthesize webview; 
@synthesize tBar, backbtn, forwardbtn; 
- (void)viewDidLoad { 
    [super viewDidLoad]; 
    [backbtn setEnabled : FALSE]; 
    [forwardbtn setEnabled : FALSE]; 
    NSString * urlAddress = @ "http://www.exampl.com"; 
    NSURL * url = [NSURL URLWithString:urlAddress]; 
    NSURLRequest * requestObj = [NSURLRequest requestWithURL:url]; 
    webview.scalesPageToFit = YES; 
    webview.autoresizesSubviews = YES; 
    [webview loadRequest : requestObj]; 
} 

- (IBAction)goBackbttn:(id)sender 
{ 
    [forwardbtn setEnabled : TRUE]; 
} 

- (IBAction)goForwardbttn:(id)sender { 
    [webview goForward]; 
} 

- (void)webViewDidFinishLoad:(UIWebView *)webView 
{ 
    [backbtn setEnabled :[webView canGoBack]]; 
    [forwardbtn setEnabled :[webView canGoForward]]; 
} 

- (void)didReceiveMemoryWarning { 
    [super didReceiveMemoryWarning]; 
} 

- (void)viewDidUnload { 
} 

- (void)dealloc { 
    [super dealloc]; 
} 
@end 

Answer 1

不應該在該

- (IBAction)goBackbttn:(id)sender 
{ 
    [forwardbtn setEnabled : TRUE]; 
} 

是這樣的：

- (IBAction)goBackbttn:(id)sender 
{ 
    [webview goBack]; 
} 

？