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https://github.com/shannah/webviewjar

Java port of the Zserge Webview. Tiny cross-platform WebView
https://github.com/shannah/webviewjar

chromium edge java ui webkit webview

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Java port of the Zserge Webview. Tiny cross-platform WebView

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README 

        
# WebView



This is a Java port of the fantastic, tiny, light-weight [WebView](https://github.com/zserge/webview) by [Serge Zaitsev](https://zserge.com).



It is packaged into an executable Jar file so that you can run it as a CLI self-contained process or as a Java library inside your current process.



## Synopsis



Cross-platform WebView that can be opened and controlled via CLI or as JavaAPI.



## Installation



Download [WebView.jar](bin/WebView.jar)



This jar can be run directly as an executable jar file (e.g. `java -jar WebView.jar [OPTIONS]`), or using the Java API by adding the jar to your classpath.



## Platform Support



Runs on Windows (32 or 64), Linux (64), and Mac.  Other platforms (e.g. Linux 32) can be supported.  Simply need to build the native libs for that platform.



## Running in Separate Process



You can run the WebView in a separate process by running:



~~~~

$ java -jar WebView.jar http://www.example.com

~~~~



This will open the web browser in its own window pointing to http://www.example.com.



**CLI Usage Instructions**



~~~~

Usage: java -jar WebView.jar [OPTIONS] 



   - A URL to a webpage to show in the webview.  

Note: You can use a data url here.



Options:

  -title 

  -w 

  -h 

  -onLoad 

  -onLoadFile 

  -useMessageBoundaries    Use message boundaries for wrapping messages from the webview.   Makes it easier to parse.



Examples:



java -jar WebView.jar https://example.com

  Opens webview with starting page https://example.com



java -jar WebView.jar "data:text/html,%3Chtml%3Ehello%3C%2Fhtml%3E"

  Opens webview that says 'hello html'



java -jar WebView.jar https://google.com \

   -onLoad "window.addEventListener('load', function(){postMessageExt('loaded '+location.href)})"

  Opens a webview, and prints out URL of each page on window load event.

~~~~



### Interacting with the Browser Environment



You can interact with the browser environment by typing into the console while the browser is running.  The browser listens on STDIN, for any input, and it will evaluate any input as Javascript in the context of the current page.  E.g. Type "alert('foo')" then `[ENTER]` to open an alert popup.  



If you need to enter a multi-line Javascript command, then begin your input with `<<{

       //.. Do something on page load.

	   // You can get the url of the page via webview.url()

    })

    .javascriptCallback(message->{

        // Handle a message sent via window.external.invoke(message)

        // message is a string.

    })

    .show();

~~~~



NOTE: The `show()` method will start a blocking event loop.



WARNING: Currently the WebView is picky about being started on the main application thread.  On Mac you may need to add the "-XstartOnFirstThread" flag in the JVM.



## Using Java API from Swing, JavaFX, or other UI Toolkit



The WebView class cannot be used from Swing, JavaFX, or any other existing UI toolkit because it starts its own event loop.  If you want to make use of the WebView from within such an app, you'll need to use the WebViewCLIClient class, which provides an interface to create and manage a WebView which runs inside its own subprocess.



See the [Swing Demo](demos/WebViewSwingDemo/README.md) for a full example of this.



The basics are:



~~~~



// Opening the webview

WebViewCLIClient webview = (WebViewCLIClient)new WebViewCLIClient.Builder()

    .url("https://www.codenameone.com")

    .title("Codename One")

    .size(800, 600)

    .build();

    

// Adding a load listener (fired whenever a page loads)

webview.addLoadListener(evt->{

    System.out.println("Loaded "+evt.getURL());

});



// Adding a message listener (fired whenever any js calls window.postMessageExt(msg))

webview.addMessageListener(evt->{

    System.out.println(evt.getMessage());

});



// Evaluate javascript on the current page.  Implicit callback() method

// allows you to return result in CompetableFuture.

webview.eval("callback(window.location.href)")

    .thenAccept(str->{

        System.out.println("Current URL is "+str);

    });

    

    



    

// Closing the webview later

webview.close();

~~~~



    



#### Demos



1. [Swing Demo](demos/WebViewSwingDemo/README.md) - A simple demo showing how to create and control a WebView from a Swing App.

2. [Minimal Demo](demos/WebViewMinimalDemo/README.md) - A simple demo that only launches a WebView on the main thread.



## Supported Platforms



This should work on Mac, Linux, and Windows.



## Building Sources



~~~

git clone https://github.com/shannah/webviewjar

cd webviewjar

ant jar

~~~



This will create dist/WebView.jar, which can be run as an executable jar.



### Troubleshooting



ANT requires that the `platforms.JDK_1.8.home` system property is set to your JAVA_HOME.  If it complains about this, you can fix the issue by changing the `ant jar` command, above, to `ant jar -Dplatforms.JDK_1.8.home="$JAVA_HOME"`.



### Rebuilding Native Libs



The repo comes with pre-built native libs in the src/windows_32, src/windows_64, src/osx_64, and src/linux_64.  If you want to make changes to these native libs, then the following information may be of use to you.



1. Use the `build-xxx.sh` (where xxx is your current platform) scripts to rebuild the native sources, and copy them into the appropriate place in the src directory.

2. Mac and linux native sources are located in the src_c directory.  Windows native sources are in the windows directory.

3. On Windows, you'll need to have Visual Studio installed (I use VS 2019, but earlier versions probably work).  Additionally, I use git bash on Windows, which is why the build-windows.sh is a bash script, and not a .bat script.



## License



MIT



## Credits



1. This library created by [Steve Hannah](https://sjhannah.com)

2. Original webview library by [Serge Zaitsev](https://zserge.com)