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/*
* libjingle
* Copyright 2013, Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.appspot.apprtc;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.util.Log;
import android.webkit.ConsoleMessage;
import android.webkit.JavascriptInterface;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
/**
* Java-land version of Google AppEngine's JavaScript Channel API:
* https://developers.google.com/appengine/docs/python/channel/javascript
*
* Requires a hosted HTML page that opens the desired channel and dispatches JS
* on{Open,Message,Close,Error}() events to a global object named
* "androidMessageHandler".
*/
public class GAEChannelClient {
private static final String TAG = "GAEChannelClient";
private WebView webView;
private final ProxyingMessageHandler proxyingMessageHandler;
/**
* Callback interface for messages delivered on the Google AppEngine channel.
*
* Methods are guaranteed to be invoked on the UI thread of |activity| passed
* to GAEChannelClient's constructor.
*/
public interface MessageHandler {
public void onOpen();
public void onMessage(String data);
public void onClose();
public void onError(int code, String description);
}
/** Asynchronously open an AppEngine channel. */
@SuppressLint("SetJavaScriptEnabled")
public GAEChannelClient(
Activity activity, String token, MessageHandler handler) {
webView = new WebView(activity);
webView.getSettings().setJavaScriptEnabled(true);
webView.setWebChromeClient(new WebChromeClient() { // Purely for debugging.
public boolean onConsoleMessage (ConsoleMessage msg) {
Log.d(TAG, "console: " + msg.message() + " at " +
msg.sourceId() + ":" + msg.lineNumber());
return false;
}
});
webView.setWebViewClient(new WebViewClient() { // Purely for debugging.
public void onReceivedError(
WebView view, int errorCode, String description,
String failingUrl) {
Log.e(TAG, "JS error: " + errorCode + " in " + failingUrl +
", desc: " + description);
}
});
proxyingMessageHandler =
new ProxyingMessageHandler(activity, handler, token);
webView.addJavascriptInterface(
proxyingMessageHandler, "androidMessageHandler");
webView.loadUrl("file:///android_asset/channel.html");
}
/** Close the connection to the AppEngine channel. */
public void close() {
if (webView == null) {
return;
}
proxyingMessageHandler.disconnect();
webView.removeJavascriptInterface("androidMessageHandler");
webView.loadUrl("about:blank");
webView = null;
}
// Helper class for proxying callbacks from the Java<->JS interaction
// (private, background) thread to the Activity's UI thread.
private static class ProxyingMessageHandler {
private final Activity activity;
private final MessageHandler handler;
private final boolean[] disconnected = { false };
private final String token;
public
ProxyingMessageHandler(Activity activity, MessageHandler handler,
String token) {
this.activity = activity;
this.handler = handler;
this.token = token;
}
public void disconnect() {
disconnected[0] = true;
}
private boolean disconnected() {
return disconnected[0];
}
@JavascriptInterface public String getToken() {
return token;
}
@JavascriptInterface public void onOpen() {
activity.runOnUiThread(new Runnable() {
public void run() {
if (!disconnected()) {
handler.onOpen();
}
}
});
}
@JavascriptInterface public void onMessage(final String data) {
activity.runOnUiThread(new Runnable() {
public void run() {
if (!disconnected()) {
handler.onMessage(data);
}
}
});
}
@JavascriptInterface public void onClose() {
activity.runOnUiThread(new Runnable() {
public void run() {
if (!disconnected()) {
handler.onClose();
}
}
});
}
@JavascriptInterface public void onError(
final int code, final String description) {
activity.runOnUiThread(new Runnable() {
public void run() {
if (!disconnected()) {
handler.onError(code, description);
}
}
});
}
}
}
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