1.网页监听APP返回键(原生goback)

假设需求：当APP点击原生导航栏左上角返回键时，APP并不返回上级VC，而是让UIWebView返回上级页面。

1.1首先

新建CMWebViewController，让其继承UIViewController，即：

• CMWebViewController.h中有：

@interface CMWebViewController : UIViewController

1.2 其次

建议基于UIViewController自建一个BackButtonHandler的分类，如UIViewController+BackButtonHandler.h和UIViewController+BackButtonHandler.m。

• UIViewController+BackButtonHandler.h

#import <UIKit/UIKit.h>

@protocol BackButtonHandlerProtocol <NSObject>

@optional

-(BOOL)navigationShouldPopOnBackButton;

@end

@interface UIViewController (BackButtonHandler) <BackButtonHandlerProtocol>

@end

• UIViewController+BackButtonHandler.m

#import "UIViewController+BackButtonHandler.h"

@implementation UIViewController (BackButtonHandler)

@end

@implementation UINavigationController (ShouldPopOnBackButton)

- (BOOL)navigationBar:(UINavigationBar *)navigationBar shouldPopItem:(UINavigationItem *)item {

    if([self.viewControllers count] < [navigationBar.items count]) {
        return YES;
    }

    BOOL shouldPop = YES;
    UIViewController* vc = [self topViewController];
    if([vc respondsToSelector:@selector(navigationShouldPopOnBackButton)]) {
        shouldPop = [vc navigationShouldPopOnBackButton];
    }

    if(shouldPop) {
        dispatch_async(dispatch_get_main_queue(), ^{
            [self popViewControllerAnimated:YES];
        });
    } else {
        // Workaround for iOS7.1. Thanks to @boliva - http://stackoverflow.com/posts/comments/34452906
        for(UIView *subview in [navigationBar subviews]) {
            if(0. < subview.alpha && subview.alpha < 1.) {
                [UIView animateWithDuration:.25 animations:^{
                    subview.alpha = 1.;
                }];
            }
        }
    }

    return NO;
}

3.最后

在实现文件CMWebViewController.m导入如上分类，并实现分类中BackButtonHandlerProtocol协议的navigationShouldPopOnBackButton方法。

• CMWebViewController.m

#import "CMWebViewController.h"
#import "UIViewController+BackButtonHandler.h"
@interface CMWebViewController ()<UIWebViewDelegate,JSObjcDelegate>

- (BOOL)navigationShouldPopOnBackButton
{
    if ([_webView canGoBack]) {
        [_webView goBack];
        return NO;
    }
    return YES;
}

2.网页监听APP返回键(OC调用JS)

假设需求：APP隐藏原生导航栏，相当于网页全屏了，当在APP中点击网页端的左上角返回键时，APP退出UIWebView并返回上级VC页面。

2.1 iOS端

CMWebViewController实现文件代码

• 导入头文件

#import <JavaScriptCore/JavaScriptCore.h>

@protocol JSObjcDelegate <JSExport>

//iosDelegate对象调用的JavaScript方法，必须声明！！！
- (void)getCall;

@end

• 代理及属性

@interface OpenHelpWebViewController ()<JSObjcDelegate>
@property (nonatomic, strong) JSContext *jsContext;
@property (weak, nonatomic) IBOutlet UIWebView *webView;
@end

• 设置JS-OC交互对象

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    
    // 设置javaScriptContext上下文
    self.jsContext = [webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];
    // 将iosDelegate对象指向自身
    self.jsContext[@"iosDelegate"] = self;
    
    self.jsContext.exceptionHandler = ^(JSContext *context, JSValue *exceptionValue) {
        context.exception = exceptionValue;
        NSLog(@"异常信息：%@", exceptionValue);
    };
}

• iosDelegate对象方法（恭候JS调用）

- (void)getCall{
    
    NSLog(@"call");
    // 之后在回调JavaScript的方法Callback把内容传出去
    dispatch_async(dispatch_get_main_queue(), ^{
        
        //APP返回上级页面动作
        [self.navigationController popViewControllerAnimated:YES];
    });
}

2.2 H5/JS端

• H5关键部分：布局元素ID

<header class="header test">
        <span>
            ![](./testFile/backIcon.png)
        </span>
        <h2 class="txt_cen">网页端标题</h2>
        <div></div>
</header>

• JS关键部分：调用OC方法

<script type="text/javascript">
 
  $("#backId").click(function(){
    var flag =  getTheFlagString("flag");
    if(flag == "h5"){
        history.go(-1);
    }else if(android){
        window.androidDelegate.getCall();
    }else if(ios){
        window.iosDelegate.getCall();
    }
  });

</script>

参考文献

• http://blog.csdn.net/coolwxb/article/details/53886796
• http://www.jianshu.com/p/fd378c6d70c0
• http://blog.csdn.net/lwjok2007/article/details/47058101
• http://blog.sina.com.cn/s/blog_12ec09c9c0102w31d.html