如何使用JSNI从GWT Java运行JavaScript函数？ [英] How to run JavaScript function from GWT Java with JSNI?

问题描述

无法从手册中了解：如何从Java运行JS函数？

例如，我在我的html页面中有一个函数：

 < script type =text / javascriptlanguage =javascript> 
函数foo（）{
 alert（'Foo！'）; 
} 
< / script> 
  

以下模块显示两个按钮，其中只有第二个按钮可用：

  public class Test_GoogleWeb_JSNI_01 implements EntryPoint {
 $ b $ public void onModuleLoad（）{
 
 Button fooButton = new Button（ 富！）; 
 fooButton.addClickHandler（new ClickHandler（）{
 public void onClick（ClickEvent event）{
 fooRunner（）; 
}; 
}）; 
 
 
 HTML fooButtonNative = new HTML（）; 
 fooButtonNative.setHTML（< input type ='button'value ='Foo Native'onclick ='foo（）'>）; 
 
 RootPanel rootPanel = RootPanel.get（）; 
 rootPanel.add（fooButton）; 
 rootPanel.add（fooButtonNative）; 
 
 
 $ b public static native void fooRunner（）/ *  -  {
 foo（）; 
}  -  * /; 
 
 
 
 
 
 $ b 
在手册中说，嵌套框架内实现的原生函数，解释情况。但是如何运行JS函数呢？
 
 
 
 更新1  
以下工作。
 
 
 
 Java： 
 
 
  public static native void fooRunner（）/ *  -  {
 $ doc.fooRunner （）; 
}  -  * /; 
  
 JS：
 < script type =text / javascriptlanguage =javascript> 
 document.fooRunner = function foo（）{
 alert（'Foo！'）; 
} 
< / script> 
  
有没有更好的方法？ 
 
解决方案
你自己回答了你的问题。有一个非常简单的理由没有更好的方法：有多种方式来部署GWT应用程序，在iframe中运行只是其中一个选项。所以这就是为什么你必须使用$ wnd变量来访问外部JS函数，所以如果你切换链接器，你的代码仍然可以正常工作。
 
Can't understand from the manual: how actually to run JS function from Java?

For example, I have a function in my html page:
<script type="text/javascript" language="javascript">
    function foo() {
        alert('Foo!');
    }
</script>
The following module shows two buttons, only second of which works:
public class Test_GoogleWeb_JSNI_01 implements EntryPoint {

public void onModuleLoad() {

    Button fooButton = new Button("Foo!");
    fooButton.addClickHandler(new ClickHandler(){
        public void onClick(ClickEvent event) {
            fooRunner();
        };
    });


    HTML fooButtonNative = new HTML();
    fooButtonNative.setHTML("<input type='button' value='Foo Native' onclick='foo()'>");

    RootPanel rootPanel = RootPanel.get();
    rootPanel.add(fooButton);
    rootPanel.add(fooButtonNative);

}

public static native void fooRunner() /*-{
  foo();
}-*/;
}
It is said in manual, that native functions implemented within nested frame, which explains the situation. But how to run JS functions then?

UPDATE 1
The following works.

Java:
public static native void fooRunner() /*-{
  $doc.fooRunner();
}-*/;
JS:
<script type="text/javascript" language="javascript">
    document.fooRunner = function foo() {
        alert('Foo!');
    }
</script>
Is there a better way?
解决方案
You answered your question yourself. There is no better way for a very simple reason: there are multiple ways to deploy GWT app, running in iframe is only one of the options. So that's why you have to use $wnd variable to access external JS function, so in case if you switch the linker , your still code will work just fine.

                        
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