我正在编写一个 chrome 插件,我想在其中注册点击事件,这意味着每当我们点击 DOM 窗口时,都会调用插件内部的处理程序。为此,我正在使用 CPlugin 类。从 NPP_New(/ argument /)调用构造函数。
当我运行浏览器并单击任意位置时,我注意到 ScriptablePluginObject 的 HasProperty 和 GetProperty 函数以标识符名称“handleEvent”调用。我不明白如何处理这个事件。
有人可以指导我吗?
/////////////CODE///////////////////
static NPIdentifier sFunction_id;
// Called from NPP_New()
CPlugin::CPlugin(NPP pNPInstance) :
m_pNPInstance(pNPInstance),
m_pNPStream(NULL),
m_bInitialized(FALSE),
m_pScriptableObject(NULL)
{
bool boRet;
NPError rv;
char szText[300];
LogMessage("CPlugin::CPlugin::Enter");
sFunction_id = NPN_GetStringIdentifier("handleEvent");
rv = NPN_GetValue(m_pNPInstance, NPNVWindowNPObject, &sWindowObj);
if (NPERR_NO_ERROR != rv)
{
LogMessage("CPlugin::CPlugin::NPN_GetValue() failed.");
}
NPObject *scriptObj = NPN_CreateObject(m_pNPInstance, GET_NPOBJECT_CLASS(ScriptablePluginObject));
if (!scriptObj)
{
LogMessage("CPlugin::CPlugin::NPN_CreateObject failed");
}
NPVariant params[3];
// arg0: event type
STRINGZ_TO_NPVARIANT("click", params[0]);
// arg1: listener
params[1].type = NPVariantType_Object;
params[1].value.objectValue = scriptObj;
// arg2: useCapture
params[2].type = NPVariantType_Bool;
params[2].value.boolValue = true;
NPIdentifier addEventListener_id = NPN_GetStringIdentifier("addEventListener");
NPVariant result_add;
// windowObject.addEventListener("click", listener, false);
if (!NPN_Invoke(m_pNPInstance, sWindowObj, addEventListener_id, ¶ms[0], 3, &result_add))
{
LogMessage("CPlugin::CPlugin::NPN_Invoke for addEventListener failed");
}
NPIdentifier removeEventListener_id = NPN_GetStringIdentifier("removeEventListener");
NPVariant result_remove;
// windowObject.removeEventListener("click", listener, false);
if (!NPN_Invoke(m_pNPInstance, sWindowObj, removeEventListener_id, ¶ms[0], 3, &result_remove))
{
LogMessage("CPlugin::CPlugin::NPN_Invoke for removeEventListener failed");
}
NPN_ReleaseVariantValue(&result_add);
NPN_ReleaseVariantValue(&result_remove);
NPN_ReleaseObject(scriptObj);
const char *ua = "This is test plugin";//NPN_UserAgent(m_pNPInstance);
strcpy(m_String, ua);
LogMessage("CPlugin::CPlugin::Exit");
}
// In HasProperty and GetProperty, nothing has been done.
bool
ScriptablePluginObject::HasProperty(NPIdentifier name)
{
LogMessage("ScriptablePluginObject::HasProperty");
char *nam = NPN_UTF8FromIdentifier(name);
LogMessage(nam);
NPN_MemFree(nam);
return true;
}
bool
ScriptablePluginObject::GetProperty(NPIdentifier name, NPVariant *result)
{
LogMessage("ScriptablePluginObject::GetProperty");
char *nam = NPN_UTF8FromIdentifier(name);
LogMessage(nam);
NPN_MemFree(nam);
return true;
}
///////////CODE///////////
以上两个类均取自谷歌代码。我只是在 NPObject 上添加事件侦听器。它有什么问题?任何的想法?
-阿拜