【CEF】 VC应用程序让JS代码能够调用C++方法
介绍
2、定一个类继承CefV8Handler，并实现Execute，用来判断js代码调用本地c++方法名称，并能够接收参数传递和返回值
3、执行js代码测试调用c++方法
Chromium和CEF使用V8 JavaScript引擎 作为它们内部的Javascript实现。浏览器中的每一页(Frame)都有它自己的JS上下文，上下文提供一个空间和安全机制来执行页面上的JS代码，CEF为客户应用程序暴露了多个JS特性，其中js扩展可实现js代码调用c++方法
实现：
1、注册一个V8扩展与js代码
void InitExtensionTest() {
// Register a V8 extension with the below JavaScript code that calls native
// methods implemented in ClientV8ExtensionHandler.
std::string code = "var cef;"
"if (!cef)"
" cef = {};"
"if (!cef.test)"
" cef.test = {};"
"(function() {"
" cef.test.__defineGetter__('test_param', function() {"
" native function GetTestParam();"
" return GetTestParam();"
" });"
" cef.test.__defineSetter__('test_param', function(b) {"
" native function SetTestParam();"
" if (b) SetTestParam(b);"
" });"
" cef.test.test_object = function() {"
" native function GetTestObject();"
" return GetTestObject();"
" };"
" cef.test.loadurl = function(val) {"
" native function loadurl();"
" return loadurl(val);"
" };"
" cef.test.IndicatorsCloud = function(val1, val2) {"
" native function IndicatorsCloud();"
" return IndicatorsCloud(val1, val2);"
" };"
"})();";
CefRegisterExtension("v8/test", code, new ClientV8ExtensionHandler());//code表示的字符串是任意合法的JS代码
}
2、定一个类继承CefV8Handler，并实现Execute，用来判断js代码调用本地c++方法名称，并能够接收参数传递和返回值
class ClientV8ExtensionHandler : public CefV8Handler {
public:
ClientV8ExtensionHandler() : test_param_("An initial string value.") {}
virtual ~ClientV8ExtensionHandler() {}
// Execute with the specified argument list and return value. Return true if
// the method was handled.
//该方法继承CefV8Handler必需实现
//功能:判断js调用的本地方法名称，接收参数传递和返回值，实现方法具体功能
virtual bool Execute(const CefString& name,
CefRefPtr<CefV8Value> object,
const CefV8ValueList& arguments,
CefRefPtr<CefV8Value>& retval,
CefString& exception) {
if (name == "SetTestParam") {
// Handle the SetTestParam native function by saving the string argument
// into the local member.
if (arguments.size() != 1 || !arguments[0]->IsString())
return false;
test_param_ = arguments[0]->GetStringValue();
return true;
} else if (name == "GetTestParam") {
// Handle the GetTestParam native function by returning the local member
// value.
retval = CefV8Value::CreateString(test_param_);
return true;
} else if (name == "GetTestObject") {
// Handle the GetTestObject native function by creating and returning a
// new V8 object.
retval = CefV8Value::CreateObject(NULL);
// Add a string parameter to the new V8 object.
retval->SetValue("param", CefV8Value::CreateString(
"Retrieving a parameter on a native object succeeded."),
V8_PROPERTY_ATTRIBUTE_NONE);
// Add a function to the new V8 object.
retval->SetValue("GetMessage",
CefV8Value::CreateFunction("GetMessage", this),
V8_PROPERTY_ATTRIBUTE_NONE);
return true;
} else if (name == "GetMessage") {
// Handle the GetMessage object function by returning a string.
retval = CefV8Value::CreateString(
"Calling a function on a native object succeeded.");
return true;
}
else if (name == "loadurl")
{
if (arguments.size() != 1)
return false;
if (arguments[0]->IsString())
{
retval = CefV8Value::CreateString( arguments[0]->GetStringValue());
}
return true;
}
else if (name == "IndicatorsCloud")
{
if (arguments.size() != 2)
return false;
if (arguments[0]->IsInt() && arguments[1]->IsString())
{
retval = CefV8Value::CreateInt(arguments[0]->GetIntValue());
}
return true;
}
return false;
}
private:
CefString test_param_;
IMPLEMENT_REFCOUNTING(ClientV8ExtensionHandler);
};
3、执行js代码测试调用c++方法
void RunExtensionTest(CefRefPtr<CefBrowser> browser) {
std::string html =
"<html><body>ClientV8ExtensionHandler says:<br><pre>"
"<script language=\"JavaScript\">"
"cef.test.test_param ="
" 'Assign and retrieve a value succeeded the first time.';"
"document.writeln(cef.test.test_param);"
"cef.test.test_param ="
" 'Assign and retrieve a value succeeded the second time.';"
"document.writeln(cef.test.test_param);"
"var obj = cef.test.test_object();"
"document.writeln(obj.param);"
"document.writeln(obj.GetMessage());"
"document.writeln(cef.test.loadurl(\"hello world.\"));"
"document.writeln(cef.test.IndicatorsCloud(123456789, \"leadsec.\"));"
"</script>"
"</pre></body></html>";
browser->GetMainFrame()->LoadString(html, "about:blank");
}