CB-8210 Use PluginResult instead of sendJavascript() for keyboard events (close #142)

- Initialize a message channel for native -> Javascript in the core App plugin
- Change keyboard detection to send events via plugin message channel, instead
  using eval() (i.e. webView.sendJavascript())

framework/src/org/apache/cordova/App.java

@@ -41,8 +41,19 @@ import java.util.HashMap;
  */
 public class App extends CordovaPlugin {
 
+    public static final String PLUGIN_NAME = "App";
     protected static final String TAG = "CordovaApp";
     private BroadcastReceiver telephonyReceiver;
+    private CallbackContext messageChannel;
+
+    /**
+     * Send an event to be fired on the Javascript side.
+     *
+     * @param action The name of the event to be fired
+     */
+    public void fireJavascriptEvent(String action) {
+        sendEventMessage(action);
+    }
 
     /**
      * Sets the context of the Command. This can then be used to do things like
@@ -100,6 +111,11 @@ public class App extends CordovaPlugin {
             else if (action.equals("exitApp")) {
                 this.exitApp();
             }
+			else if (action.equals("messageChannel")) {
+                messageChannel = callbackContext;
+                return true;
+            }
+
             callbackContext.sendPluginResult(new PluginResult(status, result));
             return true;
         } catch (JSONException e) {
@@ -249,7 +265,7 @@ public class App extends CordovaPlugin {
     public void exitApp() {
         this.webView.postMessage("exit", null);
     }
-    
+
 
     /**
      * Listen for telephony events: RINGING, OFFHOOK and IDLE
@@ -290,6 +306,18 @@ public class App extends CordovaPlugin {
         webView.getContext().registerReceiver(this.telephonyReceiver, intentFilter);
     }
 
+    private void sendEventMessage(String action) {
+        JSONObject obj = new JSONObject();
+        try {
+            obj.put("action", action);
+        } catch (JSONException e) {
+            LOG.e(TAG, "Failed to create event message", e);
+        }
+        PluginResult pluginResult = new PluginResult(PluginResult.Status.OK, obj);
+        pluginResult.setKeepCallback(true);
+        messageChannel.sendPluginResult(pluginResult);
+    }
+
     /*
      * Unregister the receiver
      *

framework/src/org/apache/cordova/CordovaWebView.java

@@ -155,7 +155,7 @@ public class CordovaWebView extends WebView {
         bridge = new CordovaBridge(pluginManager, new NativeToJsMessageQueue(this, cordova), this.cordova.getActivity().getPackageName());
         resourceApi = new CordovaResourceApi(this.getContext(), pluginManager);
 
-        pluginManager.addService("App", "org.apache.cordova.App");
+        pluginManager.addService(App.PLUGIN_NAME, "org.apache.cordova.App");
         // This will be removed in 4.0.x in favour of the plugin not being bundled.
         pluginManager.addService(new PluginEntry("SplashScreenInternal", "org.apache.cordova.SplashScreenInternal", true));
         pluginManager.init();

framework/src/org/apache/cordova/LinearLayoutSoftKeyboardDetect.java

@@ -18,10 +18,7 @@
 */
 package org.apache.cordova;
 
-import org.apache.cordova.LOG;
-
 import android.content.Context;
-//import android.view.View.MeasureSpec;
 import android.widget.LinearLayout;
 
 /**
@@ -36,6 +33,7 @@ public class LinearLayoutSoftKeyboardDetect extends LinearLayout {
     private int screenWidth = 0;
     private int screenHeight = 0;
     private CordovaActivity app = null;
+    private App appPlugin = null;
 
     public LinearLayoutSoftKeyboardDetect(Context context, int width, int height) {
         super(context);
@@ -50,7 +48,7 @@ public class LinearLayoutSoftKeyboardDetect extends LinearLayout {
      * gets smaller fire a show keyboard event and when height gets bigger fire
      * a hide keyboard event.
      *
-     * Note: We are using app.postMessage so that this is more compatible with the API
+     * Note: We are using the core App plugin to send events over the bridge to Javascript
      *
      * @param widthMeasureSpec
      * @param heightMeasureSpec
@@ -87,14 +85,12 @@ public class LinearLayoutSoftKeyboardDetect extends LinearLayout {
         // If the height as gotten bigger then we will assume the soft keyboard has
         // gone away.
         else if (height > oldHeight) {
-            if (app != null)
-                app.appView.sendJavascript("cordova.fireDocumentEvent('hidekeyboard');");
+            sendEvent("hidekeyboard");
         }
-        // If the height as gotten smaller then we will assume the soft keyboard has 
+        // If the height as gotten smaller then we will assume the soft keyboard has
         // been displayed.
         else if (height < oldHeight) {
-            if (app != null)
-                app.appView.sendJavascript("cordova.fireDocumentEvent('showkeyboard');");
+            sendEvent("showkeyboard");
         }
 
         // Update the old height for the next event
@@ -102,4 +98,15 @@ public class LinearLayoutSoftKeyboardDetect extends LinearLayout {
         oldWidth = width;
     }
 
+    private void sendEvent(String event) {
+        if (appPlugin == null) {
+            appPlugin = (App)app.appView.pluginManager.getPlugin(App.PLUGIN_NAME);
+        }
+
+        if (appPlugin == null) {
+            LOG.w(TAG, "Unable to fire event without existing plugin");
+            return;
+        }
+        appPlugin.fireJavascriptEvent(event);
+    }
 }