Most of the work is done within the fragment class BlocklyWebViewFragment. This fragment instantiates the WebView, loads the HTML (assets/blockly/webview.html), and provides a few helper methods.

Copying web assets with gradle

This android project copies the necessary files from the main Blockly repository (i.e., parent directory). In app/build.gradle, note the copyBlocklyWebFiles task and preBuild.dependsOn copyBlocklyWebFiles line.

In your own project, these files can be placed directly in the assets/blockly directory without the copy step. However, if you do use the copy step, make sure you adapt the copy paths appropriately. Additionally, you may want to update your .gitignore or similar file.

Loading Block Definitions and Generator functions

The webview.html loads the block definitions and generator functions directly into the page, without support or coordination with the Android classes. This assumes the app will always utilize the same blocks. This does not mean all blocks are visible to the user all the time; that is controlled by the toolbox and workspace files. This should accommodate almost all applications.

This does mean loading your own block definitions and generators will involve editing the HTML, adding you own <script> tag, and possibly removing the blocks_compressed.js if you do not use any standard blocks.

Connecting a Developer Console

While the console output of the WebView will be visible in the Android log (i.e., logcat), some times a more intrusive approach is required to isolate a problem. For instructions on connecting the WebView to Chrome's Developer Tools, see this article:

https://developers.google.com/web/tools/chrome-devtools/remote-debugging/

The WebView must be visible in the connect device or emulator before the WebView will included in the list of available pages to connect to.