Let’s assume we have the following class: package com.pkg One of the most important things when working with Reflection is knowing where to start, knowing what class gives us access to all that information. So… Shall we? The starting point, the Class class What can be done, what shouldn’t be done, advantages and drawbacks. In this tutorial I intent to show some basic usage of the Reflection API. The dynamism obtained by this sounds really useful, doesn’t it?
The advantage it brings to the table is the ability to analyse information regarding a class, as it’s attributes, methods, annotations, or even the state of an instance, all of that in runtime. This feature is really powerful, but as always, has to be used with some good judgement. Then you have probably already heared of Java’s Reflection API, and in case you haven’t, this is a good opportunity to see what it’s all about, and what it can be used for. – “How do I write a method that resets the state of any given object to default values?” – “How do I list all the attributes in a class dynamically?” – “How do I invoke a method, having only it’s name in a String?” If you have ever asked yourself questions like these: Register the event that opens the ad first:
#Java reflection method code#
The code example of the interface to open the ad is as follows:
public static void sendToScript ( String arg0 ) īasic Usage Using JavaScript to Trigger Java MethodsĪssuming the ad interface is set in the native layer, then when the player clicks the button to open the ad, it is logical to trigger JAVA to open the ad. public static void sendToScript ( String arg0, String arg1 ). * Java dispatch Js event, use native c++ code. public static void setCallback ( ICallback f ). * f ICallback, the method which will be actually applied. /* Add a callback which you would like to apply. void onScript ( String arg0, String arg1 ). * Applies this callback to the given argument. Wrap the behavior by creating an interface called ICallback and use setCallback to enable the interface function. onScript corresponds to onNative, which indicates the response behavior after receiving a script message. sendToScript corresponds to sendToNative and represents the parameters to be transferred to JavaScript. The corresponding JAVA interfaces are also dominated by two, including sendToScript and onScript: export function onNative ( arg0 : string, arg1 ?: string | null ): void. * Use ' = (arg0: String, arg1: String | null)=>'. * Save your own callback controller with a JavaScript function,. export function sendToNative ( arg0 : string, arg1 ?: string ): void. * Send to native with at least one argument. The developer needs to handle the operation itself. The sendToScript method is a one-way communication and does not care about the return of the lower level, nor does it tell JavaScript whether the operation succeeded or failed. onNative will only record one function at a time, and will override the original onNative method when the property is set again. 
To transfer objects containing multiple parameters, please consider converting them to the JSON format for transfer and parsing them at different levels.
This feature is still in the experimental stage, only string transfers are supported. The following points need to be noted when using them: The only two interfaces at the scripting level are sendToNative and onNative, which are transfer and receive native layer parameters, respectively. To use the previous way, please review the Using JavaScript to Call Java documentation. Note: both ways are working fine, developers can choose to use them according to their actual needs. This is a kind of channel, or a bridge, named JsbBridge before introducing other scripting systems, meaning that it serves as a bridge to communicate between script and native APP via the JSB binding. Prior to v3.4.0, the reflection mechanism in Using JavaScript to Call Java static methods, not only needed to strictly declare package names and function signatures, but also needed to strictly check the number of parameters to ensure proper operation, which was a complicated step.Īdditionally provided in v3.4.0 is another experimental method for simplifying calls from the scripting layer to the native layer. Note: After v3.6.0, jsb module is about to be deprecated, APIs will be moved to the native module of namespace cc. Sample project: simple multi-event callsĪ Simpler Way to Call Java Methods with JavaScript (Experimental). Using JAVA to Trigger JavaScript Methods. Using JavaScript to Trigger Java Methods. 
A Simpler Way to Call Java Methods with JavaScript (Experimental).
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