Scripto

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Library for easy call JS-functions from Java.

Setup

compile 'com.github.imangazalievm:scripto:2.0.1'

Using the library

Calling JS-functions from Java

We have a JS-file with some functions:

function setLogin(login) {

  document.getElementById('login_field').value = login; 
}
  function getLogin() {

  return document.getElementById('login_field').value; 
}

To call a function we should create Java-interface with JS-functions description:

public interface LoginScript {

JavaScriptFunctionCall<Void> setLogin(String login);

JavaScriptFunctionCall<String> getLogin();
  
}

Methods should be return JavaScriptFunctionCall. In the parameters of JavaScriptFunctionCall we specify type of JS-function response. In our case the first function returns nothing (Void), and the second returns text (String).

Then we should link Java-interface and JS-file:

WebView webView = ...; Scripto scripto = new Scripto.Builder(webView).build();
 LoginScript loginScript = scripto.create(LoginScript.class);

Scripts should be linked to interfaces before the page is loaded.

We can't use our script, because we need to wait for full page load. For this we need to set a listener:

scripto.onPrepared(new ScriptoPrepareListener() {

  @Override
  public void onScriptoPrepared() {

 loginScript.setLogin("MySuperLogin").call();

  
}
 
}
);

To obtain data from a function use the following syntax:

loginScript.getLogin()
  .onResponse(login -> Toast.makeText(MainActivity.this, login, Toast.LENGTH_LONG).show())
  .call();

Also we can handle errors, caused in JS-code:

.onError(error -> Toast.makeText(MainActivity.this, error.getMessage(), Toast.LENGTH_SHORT).show())

For the conversion of user-defined data type from JSON used GSON library.

If you want to get raw JSON, then necessarily to use class RawReponse:

JavaScriptFunctionCall<RawResponse> getJson();

Receiving JSON:

loginScript.getJson()
  .onResponse(response -> Toast.makeText(MainActivity.this, response.getResponse(), Toast.LENGTH_LONG).show())
  .call();

Calling Java-methods from JavaScript

Calling Java-methods from JavaScript very similar to default JavaScriptInterface. Create Java-class, which will act as JS-inteface:

public class AndroidInterface {

private Context context;

public AndroidInterface(Context context) {

this.context = context;
  
}

public void showToastMessage(String text) {

Toast.makeText(context, text, Toast.LENGTH_SHORT).show();

  
}
 
}

For correct work of JS-interface must not contain methods with the same name. Otherwis? library will throws an exception. Also we don't need to set @JavaScriptInterface annotation.

Add interface:

scripto.addInterface("Android", new AndroidInterface(context));

To call showToastMessage method we need to create JS-function with the same name:

function showToastMessage(text) {

Scripto.call('Android', arguments);
 
}
;

In the function we call special library function and pass name of JS-interface and arguments.

Calling the method from JavaScript:

showToastMessage("My super message");

Just as in Java we can use callbacks:

public String showToastMessage(String text) {

Toast.makeText(context, text, Toast.LENGTH_SHORT).show();

return "My super response"; 
}

Calling the method from JavaScript:

showToastMessage("My super message", function(responseString) {

console.log(responseString);
 
}
);

If you want to pass user-defined data type from JavaScript, convert your data to JSON via JSON.stringify(object).

If you need to protect methods from an unauthorized call, then you can protect them @JavaScriptSecure annotation:

ScriptoInterfaceConfig config = new ScriptoInterfaceConfig().enableAnnotationProtection(true);
 scripto.addInterface("Android", new AndroidInterface(this), config);

Do not forget to set an annotation on the method:

@JavaScriptSecure public void showToastMessage(String text) {

  Toast.makeText(context, text, Toast.LENGTH_SHORT).show();
 
}

License

The MIT License

Copyright (c) 2016 Mahach Imangazaliev

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.