Java tutorial
/** * Appcelerator Titanium Mobile * Copyright (c) 2009-2012 by Appcelerator, Inc. All Rights Reserved. * Licensed under the terms of the Apache Public License * Please see the LICENSE included with this distribution for details. */ package com.movento.webview.impl; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.util.HashMap; import java.util.Stack; import java.util.concurrent.Semaphore; import java.util.concurrent.TimeUnit; import org.appcelerator.kroll.KrollDict; import org.appcelerator.kroll.KrollEventCallback; import org.appcelerator.kroll.KrollLogging; import org.appcelerator.kroll.KrollModule; import org.appcelerator.kroll.common.Log; import org.appcelerator.titanium.TiApplication; import org.appcelerator.titanium.TiContext; import org.appcelerator.titanium.util.TiConvert; import org.json.JSONException; import org.json.JSONObject; import android.webkit.JavascriptInterface; import android.webkit.WebView; public class TiWebViewBinding { private static final String TAG = "TiWebViewBinding"; // This is based on binding.min.js. If you have to change anything... // - change binding.js // - minify binding.js to create binding.min.js protected final static String SCRIPT_INJECTION_ID = "__ti_injection"; protected final static String INJECTION_CODE; protected final static String SCRIPT_TAG_INJECTION_CODE; // This is based on polling.min.js. If you have to change anything... // - change polling.js // - minify polling.js to create polling.min.js protected static String POLLING_CODE = ""; static { StringBuilder jsonCode = readResourceFile("json2.js"); StringBuilder tiCode = readResourceFile("binding.min.js"); StringBuilder pollingCode = readResourceFile("polling.min.js"); if (pollingCode == null) { Log.w(TAG, "Unable to read polling code"); } else { POLLING_CODE = pollingCode.toString(); } StringBuilder scriptCode = new StringBuilder(); StringBuilder injectionCode = new StringBuilder(); scriptCode.append("\n<script id=\"" + SCRIPT_INJECTION_ID + "\">\n"); if (jsonCode == null) { Log.w(TAG, "Unable to read JSON code for injection"); } else { scriptCode.append(jsonCode); injectionCode.append(jsonCode); } if (tiCode == null) { Log.w(TAG, "Unable to read Titanium binding code for injection"); } else { scriptCode.append("\n"); scriptCode.append(tiCode.toString()); injectionCode.append(tiCode.toString()); } scriptCode.append("\n</script>\n"); jsonCode = null; tiCode = null; SCRIPT_TAG_INJECTION_CODE = scriptCode.toString(); INJECTION_CODE = injectionCode.toString(); scriptCode = null; injectionCode = null; } private Stack<String> codeSnippets; private boolean destroyed; private ApiBinding apiBinding; private AppBinding appBinding; private TiReturn tiReturn; private WebView webView; private boolean interfacesAdded = false; public TiWebViewBinding(WebView webView) { codeSnippets = new Stack<String>(); this.webView = webView; apiBinding = new ApiBinding(); appBinding = new AppBinding(); tiReturn = new TiReturn(); } public TiWebViewBinding(TiContext tiContext, WebView webView) { this(webView); } public void addJavascriptInterfaces() { if (webView != null && !interfacesAdded) { webView.addJavascriptInterface(appBinding, "TiApp"); webView.addJavascriptInterface(apiBinding, "TiAPI"); webView.addJavascriptInterface(tiReturn, "_TiReturn"); interfacesAdded = true; } } public void destroy() { // remove any event listener that have already been added to the Ti.APP through // this web view instance appBinding.clearEventListeners(); webView = null; returnSemaphore.release(); codeSnippets.clear(); destroyed = true; } private static StringBuilder readResourceFile(String fileName) { InputStream stream = TiWebViewBinding.class.getClassLoader() .getResourceAsStream("ti/modules/titanium/ui/widget/webview/" + fileName); BufferedReader reader = new BufferedReader(new InputStreamReader(stream)); StringBuilder code = new StringBuilder(); try { for (String line = reader.readLine(); line != null; line = reader.readLine()) { code.append(line + "\n"); } } catch (IOException e) { Log.e(TAG, "Error reading input stream", e); return null; } finally { if (stream != null) { try { stream.close(); } catch (IOException e) { Log.w(TAG, "Problem closing input stream.", e); } } } return code; } private Semaphore returnSemaphore = new Semaphore(0); private String returnValue; synchronized public String getJSValue(String expression) { // Don't try to evaluate js code again if the binding has already been destroyed if (!destroyed && interfacesAdded) { String code = "_TiReturn.setValue((function(){try{return " + expression + "+\"\";}catch(ti_eval_err){return '';}})());"; Log.d(TAG, "getJSValue:" + code, Log.DEBUG_MODE); returnSemaphore.drainPermits(); synchronized (codeSnippets) { codeSnippets.push(code); } try { if (!returnSemaphore.tryAcquire(3500, TimeUnit.MILLISECONDS)) { synchronized (codeSnippets) { codeSnippets.removeElement(code); } Log.w(TAG, "Timeout waiting to evaluate JS"); } return returnValue; } catch (InterruptedException e) { Log.e(TAG, "Interrupted", e); } } return null; } private class TiReturn { @JavascriptInterface public void setValue(String value) { if (value != null) { returnValue = value; } returnSemaphore.release(); } } private class WebViewCallback implements KrollEventCallback { private int id; public WebViewCallback(int id) { this.id = id; } public void call(Object data) { String dataString; if (data == null) { dataString = ""; } else if (data instanceof HashMap) { JSONObject json = TiConvert.toJSON((HashMap) data); dataString = ", " + String.valueOf(json); } else { dataString = ", " + String.valueOf(data); } String code = "Ti.executeListener(" + id + dataString + ");"; synchronized (codeSnippets) { codeSnippets.push(code); } } } @SuppressWarnings("unused") private class AppBinding { private KrollModule module; private HashMap<String, Integer> appListeners = new HashMap<String, Integer>(); private int counter = 0; private String code = null; public AppBinding() { module = TiApplication.getInstance().getModuleByName("App"); } @JavascriptInterface public void fireEvent(String event, String json) { try { KrollDict dict = new KrollDict(); if (json != null && !json.equals("undefined")) { dict = new KrollDict(new JSONObject(json)); } module.fireEvent(event, dict); } catch (JSONException e) { Log.e(TAG, "Error parsing event JSON", e); } } @JavascriptInterface public int addEventListener(String event, int id) { WebViewCallback callback = new WebViewCallback(id); int result = module.addEventListener(event, callback); appListeners.put(event, result); return result; } @JavascriptInterface public void removeEventListener(String event, int id) { module.removeEventListener(event, id); } @JavascriptInterface public void clearEventListeners() { for (String event : appListeners.keySet()) { removeEventListener(event, appListeners.get(event)); } } @JavascriptInterface public String getJSCode() { if (destroyed) { return null; } return code; } @JavascriptInterface public int hasResult() { if (destroyed) { return -1; } int result = 0; synchronized (codeSnippets) { if (codeSnippets.empty()) { code = ""; } else { result = 1; code = codeSnippets.pop(); } } return result; } } private class ApiBinding { private KrollLogging logging; public ApiBinding() { logging = KrollLogging.getDefault(); } @JavascriptInterface public void log(String level, String arg) { logging.log(level, arg); } @JavascriptInterface public void info(String arg) { logging.info(arg); } @JavascriptInterface public void debug(String arg) { logging.debug(arg); } @JavascriptInterface public void error(String arg) { logging.error(arg); } @JavascriptInterface public void trace(String arg) { logging.trace(arg); } @JavascriptInterface public void warn(String arg) { logging.warn(arg); } } }