AccessibilityInjector should return false on a failed action.

1. AccessibilityInjector was returning true even if the underlying
   JavaScript was not loaded/failed. This may lead to TalkBack getting
   stuck in a web view. To avoid this TalkBack requires gran1ularity
   change when getting into web view. This is neither advertised nor
   shown in the tutorial and which is worse it is inconsistent with
   the traversal of the app.

   Now if the action fails, false is returned and also the timeout for
   handling the action request is increased to 5s. Upon the completion
   of this timeout TalkBack may decide to show a wait dialog or just
   skip the web content. We are treating this as an ANR.

bug:6663344

Change-Id: Idf3d08fe928c495bb974a127f853de6f938e2f77

diff --git a/core/java/android/webkit/AccessibilityInjector.java b/core/java/android/webkit/AccessibilityInjector.java
index cc490bd..95694d8 100644 (file)
--- a/core/java/android/webkit/AccessibilityInjector.java
+++ b/core/java/android/webkit/AccessibilityInjector.java
@@ -43,11 +43,6 @@ import java.util.concurrent.atomic.AtomicInteger;
  * APIs.
  */
 class AccessibilityInjector {
-    // Default result returned from AndroidVox. Using true here means if the
-    // script fails, an accessibility service will always think that traversal
-    // has succeeded.
-    private static final String DEFAULT_ANDROIDVOX_RESULT = "true";
-
     // The WebViewClassic this injector is responsible for managing.
     private final WebViewClassic mWebViewClassic;
 
@@ -505,9 +500,7 @@ class AccessibilityInjector {
 
         final String jsonString = mAccessibilityJSONObject.toString();
         final String jsCode = String.format(ACCESSIBILITY_ANDROIDVOX_TEMPLATE, jsonString);
-        final String result = mCallback.performAction(mWebView, jsCode, DEFAULT_ANDROIDVOX_RESULT);
-
-        return ("true".equalsIgnoreCase(result));
+        return mCallback.performAction(mWebView, jsCode);
     }
 
     /**
@@ -518,13 +511,13 @@ class AccessibilityInjector {
                 "javascript:(function() { %s.onResult(%d, %s); })();";
 
         // Time in milliseconds to wait for a result before failing.
-        private static final long RESULT_TIMEOUT = 200;
+        private static final long RESULT_TIMEOUT = 5000;
 
         private final AtomicInteger mResultIdCounter = new AtomicInteger();
         private final Object mResultLock = new Object();
         private final String mInterfaceName;
 
-        private String mResult = null;
+        private boolean mResult = false;
         private long mResultId = -1;
 
         private CallbackHandler(String interfaceName) {
@@ -536,29 +529,27 @@ class AccessibilityInjector {
          *
          * @param webView The WebView to perform the action on.
          * @param code JavaScript code that evaluates to a result.
-         * @param defaultResult The result to return if the action times out.
          * @return The result of the action, or false if it timed out.
          */
-        private String performAction(WebView webView, String code, String defaultResult) {
+        private boolean performAction(WebView webView, String code) {
             final int resultId = mResultIdCounter.getAndIncrement();
             final String url = String.format(
                     JAVASCRIPT_ACTION_TEMPLATE, mInterfaceName, resultId, code);
             webView.loadUrl(url);
 
-            return getResultAndClear(resultId, defaultResult);
+            return getResultAndClear(resultId);
         }
 
         /**
          * Gets the result of a request to perform an accessibility action.
          *
          * @param resultId The result id to match the result with the request.
-         * @param defaultResult The default result to return on timeout.
          * @return The result of the request.
          */
-        private String getResultAndClear(int resultId, String defaultResult) {
+        private boolean getResultAndClear(int resultId) {
             synchronized (mResultLock) {
                 final boolean success = waitForResultTimedLocked(resultId);
-                final String result = success ? mResult : defaultResult;
+                final boolean result = success ? mResult : false;
                 clearResultLocked();
                 return result;
             }
@@ -569,7 +560,7 @@ class AccessibilityInjector {
          */
         private void clearResultLocked() {
             mResultId = -1;
-            mResult = null;
+            mResult = false;
         }
 
         /**
@@ -620,7 +611,7 @@ class AccessibilityInjector {
 
             synchronized (mResultLock) {
                 if (resultId > mResultId) {
-                    mResult = result;
+                    mResult = Boolean.parseBoolean(result);
                     mResultId = resultId;
                 }
                 mResultLock.notifyAll();