GWT JSNI是否支持回调? [英] Does GWT JSNI support callbacks?

问题描述

我正在构建一个使用Web SQL本地存储的GWT应用( http://dev.w3.org/html5/webdatabase/). 问题是Web SQL API使用回调函数作为 争论.

I am building a GWT app that uses Web SQL Local Storage ( http://dev.w3.org/html5/webdatabase/ ). The problem is that the Web SQL API uses callback functions as arguments.

是否可以将"Java"回调传递给JSNI?

Is it possible to pass "Java" callbacks to JSNI?

推荐答案

是的，它确实:

private static native void doThingWithCallback() /*-{
  var self = this;
  var callbackFn = $entry(function(val) {
    [e-mail](Ljava/lang/String;)(val);
  });
  $wnd.someApiThatTakesACallback(callbackFn);
}-*/;

两件事要记住:

1. $entry()提醒GWT使用调试器时要跟踪代码.
2. var self = this在函数内部保留对this的引用-否则this将是函数本身...

1. $entry() reminds GWT to keep track of the code when using the debugger.
2. var self = this keeps the reference to this inside the function -- otherwise this will be the function itself...

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