让UIWebView中实现并控制弹出窗口
UIWebView本身不支持弹出窗口，然而有需求要用，不仅需要弹出窗口，而且需要在用户关闭窗口时触发一个javascript函数。研究了一下，没有使用任何第三方库实现了。
基本的思路是在UIWebView中拦截window.open和window.close的调用。这里有2个技术问题：
1.如何在objective-c中改变javascript的行为？
我的思路是在页面加载完之后注入javascript。简单的说就是webViewDidFinishLoad中使用UIWebView 的stringByEvaluatingJavaScriptFromString注入javascript代码。
2.如何用javasript调用objective-c代码？
我使用URLScheme的方式来做。简单的来说，就是让定义2个URLScheme:
open://:用来出发弹出窗口；
back://:用来关闭窗口；后面可以跟一个参数，触发window.close之后需要回调的javascript函数;
然后在- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType中拦截URL请求就可以调用objective-c代码了。
具体的相关代码如下：
1.ViewController实现UIWebViewDelegate，在ViewDidLoad中将UIWebView的delegate设为自己:
_browser.delegate = self;
2.webViewDidFinishLoad中注入javascript
-(void) webViewDidFinishLoad:(UIWebView*)webView { // this is a pop-up window if (wvPopUp) { NSString *js = @"window.close = function () {window.location.assign(\"back://\" + window.location);};"; __unused NSString *jsOverrides = [webView stringByEvaluatingJavaScriptFromString:js]; }else { ///其他处理 NSString *js = @"window.open = function (url, d1, d2) { window.location = \"open://\" + url; }"; __unused NSString *jsOverrides = [webView stringByEvaluatingJavaScriptFromString:js]; } } } 3.在shouldStartLoadWithRequest中拦截URL请求
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{ NSString* requestURL = request.URL.absoluteString; if ([requestURL rangeOfString:@"back://"].location == 0) { [self closePopup]; return NO; } else if ([requestURL hasPrefix: @"open://"]){ NSString *newUrl = [requestURL stringByReplacingOccurrencesOfString:@"open://" withString:@""]; NSURLRequest *newRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:newUrl]]; UIWebView *wv = [self popUpWebview]; [wv loadRequest:newRequest]; return NO; } return YES; } 4.弹出窗口的objectie-c代码
- (UIWebView *) popUpWebview { // Create a web view that fills the entire window, minus the toolbar height CGRect rect = CGRectMake(_browser.frame.origin.x+20,_browser.frame.origin.y+20, _browser.frame.size.width-40,_browser.frame.size.height-40); vwPopUpContainer = [[UIView alloc] initWithFrame: rect]; vwPopUpContainer.backgroundColor = [UIColor grayColor]; [self.view addSubview:vwPopUpContainer]; CGRect rectBtn = CGRectMake(10, 10, 60, 20); btnClosePopup = [[UIButton alloc] initWithFrame:rectBtn]; [btnClosePopup setTitle:@"Close" forState:UIControlStateNormal]; [btnClosePopup addTarget:self action:@selector(closePopup) forControlEvents:UIControlEventTouchUpInside]; [vwPopUpContainer addSubview:btnClosePopup]; CGRect rectWeb = CGRectMake(10, 40, rect.size.width - 20, rect.size.height - 50); UIWebView *webView = [[UIWebView alloc] initWithFrame: rectWeb]; webView.scalesPageToFit = YES; webView.delegate = self; wvPopUp = webView; [vwPopUpContainer addSubview:wvPopUp]; return webView; } 5.关闭窗口处理包括回调触发带参数的javascript函数,这里函数名为onClosePopo
- (void) closePopup { if (wvPopUp) { NSURL *url = wvPopUp.request.URL; NSString *surl = url.absoluteString; NSUInteger pos = [surl rangeOfString:@"?"].location; NSString *paras = @""; if (pos != NSNotFound && pos < [surl length]-1) { paras = [surl substringFromIndex:pos + 1]; } NSString *js = [NSString stringWithFormat: @"onClosePopo('%@');",paras ]; __unused NSString *jsOverrides = [_browser stringByEvaluatingJavaScriptFromString:js]; [wvPopUp removeFromSuperview]; wvPopUp = nil; } if(btnClosePopup){ [btnClosePopup removeFromSuperview]; btnClosePopup = nil; } if(vwPopUpContainer){ [vwPopUpContainer removeFromSuperview]; vwPopUpContainer = nil; } }