如何知道在Cordova中使用的回调函数是否相同？

Question

I am trying to develop a cordova plugin for my android library. Below is a part of MyCordovaPlugin.js file:

var exec = require('cordova/exec');

module.exports = {
  doA : function(message, successCallback) {
      exec(successCallback,
           null, // No failure callback
           "MyCordovaPlugin",
           "doA",
           [message]);
  },
  doB : function(message, successCallback) {
      exec(successCallback,
           null, // No failure callback
           "MyCordovaPlugin",
           "doB",
           [message]);
  }
};

As mentioned above, I have two methods doA and doB which takes two arguments - message and successCallback.

In my native java code, I need to know if the successCallback used in doA and doB is same or not. How can I do this? How can I map a javascript function so that I can check if it's been used again?

I have callbackContext value in my native java code. But the value would be different when called.

Answer 1

It's not possible to distinguish at the native level one Javascript function from another, since the native layer is just passed a randomly generated ID which it uses to invoke the correct Javascript callback function.

So I would pass through an additional argument to your plugin methods which allows you to distiguish this at the native level.

Something like this:

myPlugin.js

var exec = require('cordova/exec');

module.exports = {
  doA : function(message, successCallback, callbackName) {
      exec(successCallback,
           null, // No failure callback
           "MyCordovaPlugin",
           "doA",
           [message, callbackName]);
  },
  doB : function(message, successCallback, callbackName) {
      exec(successCallback,
           null, // No failure callback
           "MyCordovaPlugin",
           "doB",
           [message, callbackName]);
  }
};

myApp.js

function foo(){
    console.log("foo");
}

function bar(){
    console.log("bar");
}

myPlugin.doA("Some message", foo, "foo");
myPlugin.doB("Some message", foo, "foo");
myPlugin.doA("Some message", bar, "bar");
myPlugin.doB("Some message", bar, "bar");

myPlugin.java

public boolean execute(String action, JSONArray args, CallbackContext callbackContext) throws JSONException {
    String message = args.getString(0);
    String callbackName = args.getString(1);
    // etc
}