ios -仿微信有多级网页时，显示返回跟关闭按钮

@property (nonatomic, copy) NSString * url;

@interface WebViewController ()<UIWebViewDelegate,UIGestureRecognizerDelegate>

@property (nonatomic, weak) UIWebView * webView;

@property (nonatomic, weak) UIButton * backItem;

@property (nonatomic, weak) UIButton * closeItem;

@property (nonatomic, weak) UIActivityIndicatorView * activityView;

@end

@implementation WebViewController

- (void)viewDidLoad {

[super viewDidLoad];

self.view.backgroundColor = [UIColor whiteColor];

[self initNaviBar];

[self initWebView];

}

- (void)initWebView{

UIWebView *webView = [[UIWebView alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];

webView.delegate = self;

[self.view addSubview:webView];

self.webView = webView;

//activityView

UIActivityIndicatorView *activityView = [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];

activityView.center = self.view.center;

[activityView startAnimating];

self.activityView = activityView;

[self.view addSubview:activityView];

//清除UIWebView的缓存

[[NSURLCache sharedURLCache] removeAllCachedResponses];

[self.webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:self.url] cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:10.0]];

}

- (void)initNaviBar{

UIView * backView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 100, 44)];

backView.backgroundColor = [UIColor purpleColor];

UIButton * backItem = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 56, 44)];

[backItem setImage:[UIImage imageNamed:@"back_arrow"] forState:UIControlStateNormal];

[backItem setImageEdgeInsets:UIEdgeInsetsMake(0, -15, 0, 0)];

[backItem setTitle:@"返回" forState:UIControlStateNormal];

[backItem setTitleEdgeInsets:UIEdgeInsetsMake(0, -15, 0, 0)];

[backItem setTitleColor:[UIColor colorWithRed:0.000 green:0.502 blue:1.000 alpha:1.000] forState:UIControlStateNormal];

[backItem addTarget:self action:@selector(clickedBackItem:) forControlEvents:UIControlEventTouchUpInside];

self.backItem = backItem;

[backView addSubview:backItem];

UIButton * closeItem = [[UIButton alloc]initWithFrame:CGRectMake(44+12, 0, 44, 44)];

[closeItem setTitle:@"关闭" forState:UIControlStateNormal];

[closeItem setTitleColor:[UIColor colorWithRed:0.000 green:0.502 blue:1.000 alpha:1.000] forState:UIControlStateNormal];

[closeItem addTarget:self action:@selector(clickedCloseItem:) forControlEvents:UIControlEventTouchUpInside];

closeItem.hidden = YES;

self.closeItem = closeItem;

[backView addSubview:closeItem];

UIBarButtonItem * leftItemBar = [[UIBarButtonItem alloc]initWithCustomView:backView];

self.navigationItem.leftBarButtonItem = leftItemBar;

self.navigationController.interactivePopGestureRecognizer.enabled = YES;

self.navigationController.interactivePopGestureRecognizer.delegate = self;

}

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer

{

if (self.webView.canGoBack) {

[self.webView goBack];

self.closeItem.hidden = NO;

return NO;

}

return YES;

}

#pragma mark - clickedBackItem

- (void)clickedBackItem:(UIBarButtonItem *)btn{

if (self.webView.canGoBack) {

[self.webView goBack];

self.closeItem.hidden = NO;

}else{

[self clickedCloseItem:nil];

}

}

#pragma mark - clickedCloseItem

- (void)clickedCloseItem:(UIButton *)btn{

[self.navigationController popViewControllerAnimated:YES];

}

#pragma mark - UIWebViewDelegate

- (void)webViewDidStartLoad:(UIWebView *)webView{

self.activityView.hidden = NO;

}

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{

NSLog(@"url: %@", request.URL.absoluteURL.description);

if (self.webView.canGoBack) {

self.closeItem.hidden = NO;

}

return YES;

}

- (void)webViewDidFinishLoad:(UIWebView *)webView{

self.activityView.hidden = YES;

self.title = [webView stringByEvaluatingJavaScriptFromString:@"document.title"];

}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error{

self.activityView.hidden = YES;

}