Warn when mising contentDescription and hint

Change-Id: I5321ba5a82c6ae2383412ecc01060f4b0d2a1c25

3 files changed, 39 insertions, 4 deletions

diff --git a/lint/libs/lint_checks/src/com/android/tools/lint/checks/AccessibilityDetector.java b/lint/libs/lint_checks/src/com/android/tools/lint/checks/AccessibilityDetector.java
index 6162c38..3572e89 100644
--- a/lint/libs/lint_checks/src/com/android/tools/lint/checks/AccessibilityDetector.java
+++ b/lint/libs/lint_checks/src/com/android/tools/lint/checks/AccessibilityDetector.java
@@ -18,12 +18,14 @@ package com.android.tools.lint.checks;
 
 import static com.android.SdkConstants.ANDROID_URI;
 import static com.android.SdkConstants.ATTR_CONTENT_DESCRIPTION;
+import static com.android.SdkConstants.ATTR_HINT;
 import static com.android.SdkConstants.ATTR_IMPORTANT_FOR_ACCESSIBILITY;
 import static com.android.SdkConstants.IMAGE_BUTTON;
 import static com.android.SdkConstants.IMAGE_VIEW;
 import static com.android.SdkConstants.VALUE_NO;
 
 import com.android.annotations.NonNull;
+import com.android.annotations.Nullable;
 import com.android.tools.lint.detector.api.Category;
 import com.android.tools.lint.detector.api.Issue;
 import com.android.tools.lint.detector.api.LayoutDetector;
@@ -37,6 +39,7 @@ import org.w3c.dom.Element;
 
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 
 /**
  * Check which looks for accessibility problems like missing content descriptions
@@ -53,7 +56,18 @@ public class AccessibilityDetector extends LayoutDetector {
             "Non-textual widgets like ImageViews and ImageButtons should use the " +
             "`contentDescription` attribute to specify a textual description of " +
             "the widget such that screen readers and other accessibility tools " +
-            "can adequately describe the user interface.",
+            "can adequately describe the user interface.\n" +
+            "\n" +
+            "Note that elements in application screens that are purely decorative " +
+            "and do not provide any content or enable a user action should not " +
+            "have accessibility content descriptions. In this case, just suppress the " +
+            "lint warning with a tools:ignore=\"ContentDescription\" attribute.\n" +
+            "\n" +
+            "Note that for text fields, you should not set both the `hint` and the " +
+            "`contentDescription` attributes since the hint will never be shown. Just " +
+            "set the `hint`. See " +
+            "http://developer.android.com/guide/topics/ui/accessibility/checklist.html#special-cases.",
+
             Category.A11Y,
             3,
             Severity.WARNING,
@@ -78,6 +92,22 @@ public class AccessibilityDetector extends LayoutDetector {
     }
 
     @Override
+    @Nullable
+    public Collection<String> getApplicableAttributes() {
+        return Collections.singletonList(ATTR_CONTENT_DESCRIPTION);
+    }
+
+    @Override
+    public void visitAttribute(@NonNull XmlContext context, @NonNull Attr attribute) {
+        Element element = attribute.getOwnerElement();
+        if (element.hasAttributeNS(ANDROID_URI, ATTR_HINT)) {
+            context.report(ISSUE, element, context.getLocation(attribute),
+                    "Do not set both contentDescription and hint: the contentDescription " +
+                    "will mask the hint", null);
+        }
+    }
+
+    @Override
     public void visitElement(@NonNull XmlContext context, @NonNull Element element) {
         if (!element.hasAttributeNS(ANDROID_URI, ATTR_CONTENT_DESCRIPTION)) {
             // Ignore views that are explicitly not important for accessibility
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/AccessibilityDetectorTest.java b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/AccessibilityDetectorTest.java
index 9f8d13d..b78455d 100644
--- a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/AccessibilityDetectorTest.java
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/AccessibilityDetectorTest.java
@@ -33,8 +33,10 @@ public class AccessibilityDetectorTest extends AbstractCheckTest {
         "res/layout/accessibility.xml:5: Warning: [Accessibility] Missing contentDescription attribute on image [ContentDescription]\n" +
         "    <ImageButton android:importantForAccessibility=\"yes\" android:id=\"@+id/android_logo2\" android:layout_width=\"wrap_content\" android:layout_height=\"wrap_content\" android:src=\"@drawable/android_button\" android:focusable=\"false\" android:clickable=\"false\" android:layout_weight=\"1.0\" />\n" +
         "    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n" +
-        "0 errors, 2 warnings\n" +
-        "",
+        "res/layout/accessibility.xml:9: Warning: Do not set both contentDescription and hint: the contentDescription will mask the hint [ContentDescription]\n" +
+        "    <EditText android:hint=\"@string/label\" android:id=\"@+android:id/summary\" android:contentDescription=\"@string/label\" />\n" +
+        "                                                                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n" +
+        "0 errors, 3 warnings\n",
 
         lintProject("res/layout/accessibility.xml"));
     }
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/layout/accessibility.xml b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/layout/accessibility.xml
index c00a880..3f45c26 100644
--- a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/layout/accessibility.xml
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/layout/accessibility.xml
@@ -1,9 +1,12 @@
 <?xml version="1.0" encoding="utf-8"?>
-<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/newlinear" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent">
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/newlinear" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent">
     <Button android:text="Button" android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>
     <ImageView android:id="@+id/android_logo" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/android_button" android:focusable="false" android:clickable="false" android:layout_weight="1.0" />
     <ImageButton android:importantForAccessibility="yes" android:id="@+id/android_logo2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/android_button" android:focusable="false" android:clickable="false" android:layout_weight="1.0" />
     <Button android:text="Button" android:id="@+id/button2" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>
     <Button android:id="@+android:id/summary" android:contentDescription="@string/label" />
     <ImageButton android:importantForAccessibility="no" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/android_button" android:focusable="false" android:clickable="false" android:layout_weight="1.0" />
+    <EditText android:hint="@string/label" android:id="@+android:id/summary" android:contentDescription="@string/label" />
+    <EditText android:id="@+android:id/summary" android:contentDescription="@string/label" />
+    <EditText tools:ignore="ContentDescription" android:hint="@string/label" android:id="@+android:id/summary" android:contentDescription="@string/label" />
 </LinearLayout>