fix NPE in accessibility bridge (flutter#13255)

Jonah Williams · web-flow · commit 6ab23d37d524 · 2019-10-21T15:35:34.000-07:00
diff --git a/shell/platform/android/io/flutter/view/AccessibilityBridge.java b/shell/platform/android/io/flutter/view/AccessibilityBridge.java
@@ -1079,7 +1079,7 @@ public AccessibilityNodeInfo findFocus(int focus) {
      */
     private SemanticsNode getRootSemanticsNode() {
         if (BuildConfig.DEBUG && !flutterSemanticsTree.containsKey(0)) {
-            Log.e(TAG, "Attempted to getRootSemanticsNode without a root sematnics node.");
+            Log.e(TAG, "Attempted to getRootSemanticsNode without a root semantics node.");
         }
         return flutterSemanticsTree.get(0);
     }
@@ -1140,6 +1140,9 @@ public boolean onAccessibilityHoverEvent(MotionEvent event) {
         if (!accessibilityManager.isTouchExplorationEnabled()) {
             return false;
         }
+        if (flutterSemanticsTree.isEmpty()) {
+            return false;
+        }
 
         SemanticsNode semanticsNodeUnderCursor = getRootSemanticsNode().hitTest(new float[] {event.getX(), event.getY(), 0, 1});
         if (semanticsNodeUnderCursor.platformViewId != -1) {

Original file line number	Diff line number	Diff line change
`@@ -1079,7 +1079,7 @@ public AccessibilityNodeInfo findFocus(int focus) {`
`1079`	`1079`	`*/`
`1080`	`1080`	`private SemanticsNode getRootSemanticsNode() {`
`1081`	`1081`	`if (BuildConfig.DEBUG && !flutterSemanticsTree.containsKey(0)) {`
`1082`		`- Log.e(TAG, "Attempted to getRootSemanticsNode without a root sematnics node.");`
	`1082`	`+ Log.e(TAG, "Attempted to getRootSemanticsNode without a root semantics node.");`
`1083`	`1083`	`}`
`1084`	`1084`	`return flutterSemanticsTree.get(0);`
`1085`	`1085`	`}`
`@@ -1140,6 +1140,9 @@ public boolean onAccessibilityHoverEvent(MotionEvent event) {`
`1140`	`1140`	`if (!accessibilityManager.isTouchExplorationEnabled()) {`
`1141`	`1141`	`return false;`
`1142`	`1142`	`}`
	`1143`	`+ if (flutterSemanticsTree.isEmpty()) {`
	`1144`	`+ return false;`
	`1145`	`+ }`
`1143`	`1146`
`1144`	`1147`	`SemanticsNode semanticsNodeUnderCursor = getRootSemanticsNode().hitTest(new float[] {event.getX(), event.getY(), 0, 1});`
`1145`	`1148`	`if (semanticsNodeUnderCursor.platformViewId != -1) {`