iOS Swift JavaScript与iOS原生交互

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第一种：uiwebview和js交互

1、初始化
    self.webView2 = [[UIWebView alloc] initWithFrame:self.view.frame];
    _webView2.delegate = self;
        NSURLRequest *url = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://112.124.54.19/Score/cet.html"]];
    [self.webView2 loadRequest:url];
    [self.view addSubview:self.webView2];
    self.whiteView.hidden = NO;//一个白色的View主要是遮盖未修改的html界面


2、实现代理方法
-(void)webViewDidFinishLoad:(UIWebView *)webView{
    //删除图片
    NSString * p = @"var  p = document.getElementsByClassName('pic');";
    NSString * r = @"p[0].remove();";
    NSString * java = [NSString stringWithFormat:@"%@%@",p,r];
    //替换文字
    NSString * text_p = @"var  p = document.getElementsByClassName('tips-hold');";
    NSString * text_r = @"p[0].innerHTML='XXX四六级英语查询';";
    NSString * text_java = [NSString stringWithFormat:@"%@%@",text_p,text_r];
    //修改按钮颜色
    NSString * btn_p = @"var p = document.getElementById('submit-btn');";
    NSString * btn_r = @"p.style.backgroundColor='#4CA4FE';";
    NSString * btn_java = [NSString stringWithFormat:@"%@%@",btn_p,btn_r];
    JSContext *context = [webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];
    [context evaluateScript:java];
    [context evaluateScript:text_java];
    [context evaluateScript:btn_java]；
    self.whiteView.hidden = YES;
}

第二种：WKWebView与js交互

1、初始化
    WKWebView *webView = [[WKWebView alloc] initWithFrame:self.view.frame];
    webView.allowsBackForwardNavigationGestures = YES;
    NSURLRequest *url = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://112.124.54.19/Score/cet.html"]];
    [webView loadRequest:url];
    webView.navigationDelegate = self;
    [self.view addSubview:webView];
    self.webView = webView;

2、实现代理方法

-(void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation{
    
    //删除图片
    NSString * p = @"var  p = document.getElementsByClassName('pic');";
    NSString * r = @"p[0].remove();";
    NSString * java = [NSString stringWithFormat:@"%@%@",p,r];
    
    //替换文字
    NSString * text_p = @"var  p = document.getElementsByClassName('tips-hold');";
    NSString * text_r = @"p[0].innerHTML='XXX四六级英语查询';";
    NSString * text_java = [NSString stringWithFormat:@"%@%@",text_p,text_r];
    
    //修改按钮颜色
    NSString * btn_p = @"var p = document.getElementById('submit-btn');";
    NSString * btn_r = @"p.style.backgroundColor='#4CA4FE';";
    NSString * btn_java = [NSString stringWithFormat:@"%@%@",btn_p,btn_r];
   
    [webView evaluateJavaScript:java completionHandler:nil];
    [webView evaluateJavaScript:text_java completionHandler:nil];
    [webView evaluateJavaScript:btn_java completionHandler:nil];
    self.whiteView.hidden = YES;
}

显示加载进度条

-(UIProgressView *)progressView{
    if (!_progressView) {
        _progressView = [[UIProgressView alloc] initWithFrame:CGRectMake(0, 64, self.view.frame.size.width, 2)];
        _progressView.progressTintColor = [UIColor redColor];
        [self.view addSubview:_progressView];
    }
    return _progressView;
}


1、监听属性
 //添加监听
    [self.webView addObserver:self forKeyPath:@"estimatedProgress" options:NSKeyValueObservingOptionNew context:nil];

2、监听属性变化执行
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context{
    if ([keyPath isEqualToString:@"estimatedProgress"]) {
        self.progressView.progress = self.webView.estimatedProgress;
        //加载完成
        if (self.webView.estimatedProgress >=1.0) {
            [UIView animateWithDuration:0.25 animations:^{
                self.progressView.alpha = 0.0f;
                self.progressView.progress = 0.0f;
            }];
        }else{
            self.progressView.alpha = 1.0f;
        }
    }
}

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