Delphi中Chrome Chromium、Cef3学习笔记（三）

原文   http://blog.csdn.net/xtfnpgy/article/details/46635871

Delphi与JS的交互问题：

一、执行简单的JS

上一篇已经讲过:

chrm1.browser.MainFrame.ExecuteJavaScript('alert("abc");','about:blank',0);

chrm1.browser.MainFrame.ExecuteJavaScript('function aaa(){alert("abc");}aaa();','about:blank',0);

二、注入自定义的JS

首先必须在网页加载完成之后，才可以执行，不能为空页面！

str_js := 'var oScript = document.createElement( "script" );oScript.id = "sid";alert(oScript.id);';
chrm1.browser.MainFrame.ExecuteJavaScript(str_js,'about:blank',0);

三、delphi与JS交互（通过ceflib实现）

Cef3的Demo里面，有一个cefclient的例子，可以看下，关键代码：

1TExtension = class(TCefv8HandlerOwn)
2  private
3    FTestParam: ustring;
4  protected
5    function Execute(const name: ustring; const obj: ICefv8Value;
6      const arguments: TCefv8ValueArray; var retval: ICefv8Value;
7      var exception: ustring): Boolean; override;  //重写Execute事件
8  end;

//通过不同的name，执行不同的动作

1function TExtension.Execute(const name: ustring; const obj: ICefv8Value;
2  const arguments: TCefv8ValueArray; var retval: ICefv8Value;
3  var exception: ustring): Boolean;
4begin
5  if(name = 'SetTestParam') then
6  begin
7    // Handle the SetTestParam native function by saving the string argument
8    // into the local member.
9    if (Length(arguments) <> 1) or (not arguments[0].IsString) then
10    begin
11      Result := false;
12      Exit;
13    end;
14    FTestParam := arguments[0].GetStringValue;  //多个参数arguments[i].GetStringValue 依次类推
15    Result := true;
16  end
17  else if(name = 'GetTestParam') then
18  begin
19    // Handle the GetTestParam native function by returning the local member
20    // value.
21    retval := TCefv8ValueRef.CreateString(Ftestparam);
22    Result := true;
23  end
24  else if (name = 'GetTestObject') then
25  begin
26    // Handle the GetTestObject native function by creating and returning a
27    // new V8 object.
28    retval := TCefv8ValueRef.CreateObject(nil);
29    // Add a string parameter to the new V8 object.
30    retval.SetValueByKey('param', TCefv8ValueRef.CreateString(
31        'Retrieving a parameter on a native object succeeded.'));
32    // Add a function to the new V8 object.
33    retval.SetValueByKey('GetMessage',
34        TCefv8ValueRef.CreateFunction('GetMessage', Self));
35    Result := true;
36  end
37  else if(name = 'GetMessage') then
38  begin
39    // Handle the GetMessage object function by returning a string.
40    retval := TCefv8ValueRef.CreateString(
41        'Calling a function on a native object succeeded.');
42    Result := true;
43  end else
44    Result := false;
45end;

{ 注册JS扩展 }

1procedure RegisterExtension;
2var
3  Code: string;
4begin
5  Code :=
6    'var cef;if(!cef)cef={};if(!cef.taobao)cef.taobao={};(function(){cef.taobao.test_object=function(){native function GetTestObject();return GetTestObject();};})();';
7  if Code <> '' then
8  try
9    CefRegisterExtension('example/v8',Code,TExtension.Create as ICefv8Handler);
10  except
11  end;
12end;

在FormCreate中注册类：
RegisterExtension;

调用实例：

chrm1.browser.MainFrame.ExecuteJavaScript('alert("abc");','about:blank',0);

  str_temp := 'function aaa(){var CefObj = new cef.taobao.test_object;'+  //先new一个实例对象
               'CefObj.SetTestParam("abc");var b=CefObj.GetTestParam();alert(b);'+   //设置、获取、输出参数
               '}aaa();';
  chrm1.Browser.MainFrame.ExecuteJavaScript(str_temp,'about:blank',0);

如果要实现多个参数，可以定义个数组替代FTestParam 

  private
    FTestParam : ustring;
    ArrayParam : array of ustring;  //多个参数

关键代码：

1if(name = 'SetTestParam') then
2  begin
3// **************原来一个参数的情况**********
4//    if (Length(arguments) <> 1) or (not arguments[0].IsString) then
5//    begin
6//      Result := false;
7//      Exit;
8//    end;
9//    FTestParam  := arguments[0].GetStringValue;
10// **************原来一个参数的情况**********
11    SetLength(ArrayParam,Length(arguments));
12    for  i := 0 to Length(arguments) - 1 do
13    begin
14      ArrayParam[i] := arguments[i].GetStringValue;
15      if s='' then
16        s := ArrayParam[i]
17      else
18        s  := s+','+ArrayParam[i];
19    end;
20    FTestParam  := s;
21  end
22  else if(name = 'GetTestParam') then
23  begin
24// **************原来一个参数的情况**********
25//    retval := TCefv8ValueRef.CreateString(FTestParam);
26// **************原来一个参数的情况**********
27    for  i := 0 to Length(ArrayParam) - 1 do
28    begin
29      if s='' then
30        s := ArrayParam[i]
31      else
32        s  := s+','+ArrayParam[i];
33    end;
34    retval := TCefv8ValueRef.CreateString(FTestParam);
35  end;

这样调用GetTestParam返回的还是一个字符串，多个参数用逗号隔开了而已，可以对其再进行改写即可；