JPXUIWebViewJSBridge

simplify invocation between Objective C and Javascript Code

Background

Guys know that the magic of Javascript can invoke Objective C code lies in

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

Generally Speaking, we will implement code like this to achieve:

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
  if ([request.URL.absoluteString hasPrefix:@"js-call://user/set"]) {
    NSDictionary *parameters = [self parseQueryString:request.URL.absoluetString];
    [self executeSomeObjectiveCCodeWithParameters:parameters];
    return NO;
  } else if ([request.URL.absoluteString hasPrefix:@"js-call://user/get"]) {
    NSDictionary *parameters = [self parseQueryString:request.URL.absoluetString];
    [self executeSomeObjectiveCCodeWithParameters:parameters];
    return NO;
  } else if (...) {
    ...
  }
  return YES;
}

So, there will be a lot of if ... else if ... else code. And the exposed methods can not be aware at a glance. That is Why I create JPXUIWebViewJSBridge to handle this embarrassment.

Usage

Initialization

//self can be either ViewController or NSObject, it is the place that exposes Objective C methods to web.
self.bridge = [[JPXUIWebViewJSBridge alloc] initWithHandler:self];

Config

//here, element in routines is an array, the first item of the element is url pattern, the second one is your exposed method implementation.
self.bridge.routines = @[@[@"^js-call://user/set.*$", @"setUser"],
                         @[@"^js-call://user/get.*$", @"getUser"]
                         ];

Invocation in UIWebViewDelegate

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
    NSError *error;
    BOOL canHandleRequest = [self.bridge canHandleRequest:request error:&error];
    if (canHandleRequest) {
        [self.bridge handleRequest:request error:&error];
        NSLog(@"error1:%@", [error localizedDescription]);
        return NO;
    } else {
        NSLog(@"error2:%@", [error localizedDescription]);
    }
    return YES;
}

Implementation of exposed Objective C method

- (void) methodName:(NSDictionary *)parametersFromWeb
{
    ...
}

Invocation in web(javascript)

//example only.
function execute(url)
{
     var iframe = document.createElement("IFRAME");
     iframe.setAttribute("src", url);
     document.documentElement.appendChild(iframe);
     iframe.parentNode.removeChild(iframe);
     iframe = null;
}
execute('js-call://user/set?uid=1&name=jpx');

Compatibility

use ARC, iOS 5.0+ support.