SketchActivity.java

package com.fiskur.p5;

import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.app.Activity;
import android.content.res.AssetManager;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.MenuItem;
import android.view.Window;
import android.webkit.WebView;
import android.widget.Toast;

public class SketchActivity extends Activity {

  private WebView webview;
	private AssetManager mAssetManager;
	public static final String SKETCHDIR = Environment.getExternalStorageDirectory().getPath() + "/sketch/";

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		
		//We want fullscreen so hide actionbar
		getWindow().requestFeature(Window.FEATURE_ACTION_BAR);
		getActionBar().hide();
		
		setContentView(R.layout.activity_sketch);

		//Needed to copy processingjs and html file from assets/
		mAssetManager = getResources().getAssets();

		//The sourcecode passed in from the coding edittext
		String source = getIntent().getStringExtra("source");
		
		webview = (WebView) findViewById(R.id.webview);
		
		setupSketch(source);
	}

	//Copy ProcessingJS and html file from assets/ if they've not been copied already
	//Save sketch.pde file containing source to run
	private void setupSketch(String source) {
		
		File sketchDir = new File(SKETCHDIR);
		
		//If first-run create output directory
		if(!sketchDir.exists()){
			sketchDir.mkdir();
		}
		
		//The files contained in assets/
		String[] files = new String[] { "processing-1.4.1.min.js", "sketch.html" };
		
		for (String filename : files) {
			File outFile = new File(sketchDir, filename);
			if (!outFile.exists()) {
				try {
					InputStream in = mAssetManager.open(filename);
					OutputStream out = new FileOutputStream(outFile);
					copyFile(in, out);
					in.close();
					in = null;
					out.flush();
					out.close();
					out = null;
				} catch (IOException e) {
					showToast("Failed to copy asset file: " + filename + "\n" + e.toString());
					return;
				}
			}
		}
		
		//Save sketch.pde
		File sketch = new File(sketchDir, "sketch.pde");
		try {
			FileWriter writer = new FileWriter(sketch);
			writer.append(source);
			writer.close();
		} catch (IOException e) {
			showToast("Failed to load sketch: " + e.toString());
			return;
		}
		
		//Finally pass the file location to the WebView
		String path = sketchDir.getPath() + "/sketch.html";
		webview.getSettings().setAllowUniversalAccessFromFileURLs(true);
		webview.getSettings().setJavaScriptEnabled(true);
		webview.loadUrl("file://" + path);
	}

	public static void copyFile(InputStream in, OutputStream out) throws IOException {
		byte[] buffer = new byte[1024];
		int read;
		while ((read = in.read(buffer)) != -1) {
			out.write(buffer, 0, read);
		}
	}
	
	//Convenience method for displaying messages to user
	private void showToast(String error){
		Toast.makeText(SketchActivity.this, error, Toast.LENGTH_LONG).show();
	}
}