1 webView的使用

• 优点:能在当前app中打开网址,适配 iOS7
• 缺点:没有功能,如果需要功能,只能自己实现

1.1 webView加载网页

    NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
  // 设置内边距
    self.webView.scrollView.contentInset = UIEdgeInsetsMake(50, 0, 0, 0);
  //内容是否自适应
    self.webView.scalesPageToFit = YES;
    [self.webView loadRequest:request];

1.2 webView加载本地文件

    NSURL *url = [NSURL fileURLWithPath:@"/Users/Desktop/123.mp4"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [self.webView loadRequest:request];

1.3 webView加载本地html

     NSURL *url = [[NSBundle mainBundle] URLForResource:@"text.html" withExtension:nil];
     NSURLRequest *request = [NSURLRequest requestWithURL:url];
// 检测特殊字符的样式
    self.webView.dataDetectorTypes = UIDataDetectorTypeAll;
    [self.webView loadRequest:request];

1.4 webView的前进/后退/刷新

   - (void)viewDidLoad {
    [super viewDidLoad];
    NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"];
     NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [self.webView loadRequest:request];
   // 先要遵守UIWebViewDelegate代理 
    self.webView.delegate = self;
}
- (IBAction)goBackBtnClick:(id)sender {
    [self.webView goBack];
}
- (IBAction)goForwardBtnClick:(id)sender {
    [self.webView goForward];
}
- (IBAction)reloadBtnClick:(id)sender {
    [self.webView reload];
}

#pragma mark UIWebViewDelegate
-(void)webViewDidFinishLoad:(UIWebView *)webView
{ 
    self.goBack.enabled = self.webView.canGoBack;
    self.goForward.enabled = self.webView.canGoForward;
}

2 SFSafariViewController的使用

• 优点:把Safari封装成了一个控制器
• 缺点:iOS9以后才能使用
• 使用步骤:
  1.导入#import <SafariServices/SafariServices.h>
  2.推荐使用Modal,但也可以使用 push

 NSURL *url = [NSURL URLWithString:item.url];
    SFSafariViewController *safariVc = [[SFSafariViewController alloc] initWithURL:url];
1.push的方式
   // SFSafariViewController顶部条 会与 导航条冲突,显示顶部条,一定要记得隐藏导航条
   self.navigationController.navigationBar.hidden = YES;
   safariVc.delegate = self;  // 遵守SFSafariViewControllerDelegate代理
    [self.navigationController pushViewController:safariVc animated:YES];
// 默认不能返回,需要在代理方法中作返回处理
-(void)safariViewControllerDidFinish:(SFSafariViewController *)controller {
  [self.navigationController popViewControllerAnimated:YES];
}

2.Model 的方式
    [self presentViewController:safariVc animated:YES completion:nil];
备注:具备返回的功能,不需要额外处理(推荐)

3 WKWebView控件 (UIWebView 的升级版)

-优点:可以监听进度条,比UIWebView功能更加多
-缺点: iOS 8以后
-使用:1.#import <WebKit/WebKit.h> 2.需要手动把WebKit框架编译

- (void)viewDidLoad {
    [super viewDidLoad];
    WKWebView *webView = [[WKWebView alloc] init];
    [_contentView addSubview:webView];
    
    // 添加底部额外滚动区域
    webView.scrollView.contentInset = UIEdgeInsetsMake(0, 0, 44, 0);
    
    // 展示网页
    NSURLRequest *request = [NSURLRequest requestWithURL:_url];
    [webView loadRequest:request];
// 前进,后退,刷新,进度条
    // KVO监听属性
    // Observer:观察者
    // KeyPath:监听哪个属性
    // options:NSKeyValueObservingOptionNew,监听新值改变
    [webView addObserver:self forKeyPath:@"canGoBack" options:NSKeyValueObservingOptionNew context:nil];
    [webView addObserver:self forKeyPath:@"canGoForward" options:NSKeyValueObservingOptionNew context:nil];
    [webView addObserver:self forKeyPath:@"estimatedProgress" options:NSKeyValueObservingOptionNew context:nil];
    [webView addObserver:self forKeyPath:@"title" options:NSKeyValueObservingOptionNew context:nil];
}

- (void)viewDidLayoutSubviews
{
    [super viewDidLayoutSubviews];
    WKWebView *webView = _contentView.subviews[0];
    webView.frame = _contentView.bounds;
}

// 监听属性有新值就会调用
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context
{
    _backItem.enabled = _webView.canGoBack;
    _forwardItem.enabled = _webView.canGoForward;
    _progressView.progress = _webView.estimatedProgress;
    _progressView.hidden = _webView.estimatedProgress>= 1;
    self.title = _webView.title;
}
// 对象即将销毁,移除观察者
- (void)dealloc
{
    [_webView removeObserver:self forKeyPath:@"canGoBack"];
    [_webView removeObserver:self forKeyPath:@"canGoForward"];
    [_webView removeObserver:self forKeyPath:@"estimatedProgress"];
    [_webView removeObserver:self forKeyPath:@"title"];
}
// 后退
- (IBAction)back:(id)sender {
    [_webView goBack];
}

// 前进
- (IBAction)forward:(id)sender {
    [_webView goForward];
}

// 刷新
- (IBAction)refresh:(id)sender {
    [_webView reload];
}