1.UIWebView的内容控制的属性／方法列表

loading属性               确认当前页面是否在读入中

canGoForward属性   确认goForward  方法是否可运行，可运行为yes；

canGoBack属性        确认goBack  方法是否可运行，可运行为yes。

goBack方法               返回前一个页面

goForword方法          进入下一个页面

reload方法                 又一次读入当前页

stopLoading方法       中止当前页的读入

2.webViewController.h

@interface webViewController : UIViewController<UIWebViewDelegate,UINavigationControllerDelegate,UINavigationBarDelegate>
{
    UIWebView *_webView;
}

@property(nonatomic,strong)UIBarButtonItem *reloadButton;
@property(nonatomic,strong)UIBarButtonItem *stopButton;
@property(nonatomic,strong)UIBarButtonItem *backButton;
@property(nonatomic,strong)UIBarButtonItem *forwardButton;
@end

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.navigationItem.title = @"UIWebView測试版";
    _webView = [[UIWebView alloc]init];
    _webView.delegate = self;
    _webView.frame = self.view.frame;
    _webView.autoresizingMask = UIViewAutoresizingFlexibleHeight|UIViewAutoresizingFlexibleWidth;
    _webView.scalesPageToFit = YES;
    [self.view addSubview:_webView];
    //工具条中追加按钮
    _reloadButton = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemRefresh target:self action:@selector(reloadDidPush)];
    _stopButton = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemStop target:self action: @selector(stopDidPush)];
    _backButton = [[UIBarButtonItem alloc]initWithTitle:@"back" style:UIBarButtonItemStyleBordered target:self action:@selector(backDidPush)];
    _forwardButton = [[UIBarButtonItem alloc]initWithTitle:@"Forward" style:UIBarButtonItemStyleBordered target:self action:@selector(forwardDidPush)];
    NSArray *buttons = [NSArray arrayWithObjects:_backButton,_forwardButton,_reloadButton,_stopButton, nil];
   [self setToolbarItems:buttons animated:YES];
    [self.navigationController setToolbarHidden:NO animated:YES];
    

}
-(void)reloadDidPush
{
    [_webView reload];//又一次读入页面
}
-(void)stopDidPush
{
    if(_webView.loading){
        [_webView stopLoading];//读入停止
    }
    
}
-(void)backDidPush
{
    if (_webView.canGoBack) {
        [_webView goBack];//返回前一画面
    }
}
-(void)forwardDidPush
{
    if (_webView.canGoForward) {
        [_webView goForward];//进入下一页面
    }
    
}

-(void)updateControlEnabled
{
    //统一更新指示按钮状态
    [UIApplication sharedApplication].networkActivityIndicatorVisible = _webView.loading;
    _stopButton.enabled = _webView.loading;
    _backButton.enabled = _webView.canGoBack;
    _forwardButton.enabled = _webView.canGoForward;
    
}
-(void)viewDidAppear:(BOOL)animated

{
    //画面显示结果后读入web页面画面
    [super viewDidAppear:animated];
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.baidu.com"]];
    [_webView loadRequest:request];
    [self updateControlEnabled];
}
-(void)viewWillDisappear:(BOOL)animated
{
    //画面关闭时状态的活动指示器设置成off
    [super viewWillDisappear:animated];
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}

-(void)webViewDidStartLoad:(UIWebView *)webView{
    [self updateControlEnabled];
}

-(void)webViewDidFinishLoad:(UIWebView *)webView

{
    [self updateControlEnabled];
}
-(void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
{
    [self updateControlEnabled];
}