Fix 22848: Lint: Bogus suggestion and fix for flattening layout

TabHosts etc should not be eligible as parents for an unused layout.

Change-Id: Ic934046530a5c8a4ff84a873e63230819f4fd4a5

3 files changed, 54 insertions, 9 deletions

diff --git a/lint/libs/lint_checks/src/com/android/tools/lint/checks/UselessViewDetector.java b/lint/libs/lint_checks/src/com/android/tools/lint/checks/UselessViewDetector.java
index 5fe9119..1404a9a 100644
--- a/lint/libs/lint_checks/src/com/android/tools/lint/checks/UselessViewDetector.java
+++ b/lint/libs/lint_checks/src/com/android/tools/lint/checks/UselessViewDetector.java
@@ -16,15 +16,21 @@
 
 package com.android.tools.lint.checks;
 
+import static com.android.tools.lint.detector.api.LintConstants.ABSOLUTE_LAYOUT;
 import static com.android.tools.lint.detector.api.LintConstants.ANDROID_URI;
 import static com.android.tools.lint.detector.api.LintConstants.ATTR_BACKGROUND;
 import static com.android.tools.lint.detector.api.LintConstants.ATTR_ID;
 import static com.android.tools.lint.detector.api.LintConstants.FRAME_LAYOUT;
+import static com.android.tools.lint.detector.api.LintConstants.GRID_LAYOUT;
 import static com.android.tools.lint.detector.api.LintConstants.GRID_VIEW;
 import static com.android.tools.lint.detector.api.LintConstants.HORIZONTAL_SCROLL_VIEW;
 import static com.android.tools.lint.detector.api.LintConstants.LINEAR_LAYOUT;
 import static com.android.tools.lint.detector.api.LintConstants.MERGE;
+import static com.android.tools.lint.detector.api.LintConstants.RADIO_GROUP;
+import static com.android.tools.lint.detector.api.LintConstants.RELATIVE_LAYOUT;
 import static com.android.tools.lint.detector.api.LintConstants.SCROLL_VIEW;
+import static com.android.tools.lint.detector.api.LintConstants.TABLE_LAYOUT;
+import static com.android.tools.lint.detector.api.LintConstants.TABLE_ROW;
 
 import com.android.tools.lint.detector.api.Category;
 import com.android.tools.lint.detector.api.Issue;
@@ -82,29 +88,28 @@ public class UselessViewDetector extends LayoutDetector {
         return Speed.FAST;
     }
 
-    private static final List<String> CONTAINERS = new ArrayList<String>(20);
+    private static final List<String> CONTAINERS = new ArrayList<String>(18);
     static {
-        CONTAINERS.add("android.gesture.GestureOverlayView"); //$NON-NLS-1$
-        CONTAINERS.add("AbsoluteLayout");                     //$NON-NLS-1$
+        CONTAINERS.add(ABSOLUTE_LAYOUT);
         CONTAINERS.add(FRAME_LAYOUT);
-        CONTAINERS.add("GridLayout");                         //$NON-NLS-1$
+        CONTAINERS.add(GRID_LAYOUT);
         CONTAINERS.add(GRID_VIEW);
         CONTAINERS.add(HORIZONTAL_SCROLL_VIEW);
         CONTAINERS.add("ImageSwitcher");                      //$NON-NLS-1$
         CONTAINERS.add(LINEAR_LAYOUT);
-        CONTAINERS.add("RadioGroup");                         //$NON-NLS-1$
-        CONTAINERS.add("RelativeLayout");                     //$NON-NLS-1$
+        CONTAINERS.add(RADIO_GROUP);
+        CONTAINERS.add(RELATIVE_LAYOUT);
         CONTAINERS.add(SCROLL_VIEW);
         CONTAINERS.add("SlidingDrawer");                      //$NON-NLS-1$
         CONTAINERS.add("StackView");                          //$NON-NLS-1$
-        CONTAINERS.add("TabHost");                            //$NON-NLS-1$
-        CONTAINERS.add("TableLayout");                        //$NON-NLS-1$
-        CONTAINERS.add("TableRow");                           //$NON-NLS-1$
+        CONTAINERS.add(TABLE_LAYOUT);
+        CONTAINERS.add(TABLE_ROW);
         CONTAINERS.add("TextSwitcher");                       //$NON-NLS-1$
         CONTAINERS.add("ViewAnimator");                       //$NON-NLS-1$
         CONTAINERS.add("ViewFlipper");                        //$NON-NLS-1$
         CONTAINERS.add("ViewSwitcher");                       //$NON-NLS-1$
         // Available ViewGroups that are not included by this check:
+        //  CONTAINERS.add("android.gesture.GestureOverlayView");
         //  CONTAINERS.add("AdapterViewFlipper");
         //  CONTAINERS.add("DialerFilter");
         //  CONTAINERS.add("ExpandableListView");
@@ -113,6 +118,7 @@ public class UselessViewDetector extends LayoutDetector {
         //  CONTAINERS.add("merge");
         //  CONTAINERS.add("SearchView");
         //  CONTAINERS.add("TabWidget");
+        //  CONTAINERS.add("TabHost");
     }
     @Override
     public Collection<String> getApplicableElements() {
@@ -178,6 +184,12 @@ public class UselessViewDetector extends LayoutDetector {
             return;
         }
 
+        // Certain parents are special - such as the TabHost and the GestureOverlayView -
+        // where we want to leave things alone.
+        if (!CONTAINERS.contains(parentTag)) {
+            return;
+        }
+
         boolean hasId = element.hasAttributeNS(ANDROID_URI, ATTR_ID);
         Location location = context.getLocation(element);
         String tag = element.getTagName();
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/UselessViewDetectorTest.java b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/UselessViewDetectorTest.java
index 845d6fb..aa45894 100644
--- a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/UselessViewDetectorTest.java
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/UselessViewDetectorTest.java
@@ -37,4 +37,11 @@ public class UselessViewDetectorTest extends AbstractCheckTest {
                 "no background, no id)",
             lintFiles("res/layout/useless.xml"));
     }
+
+    public void testTabHost() throws Exception {
+        assertEquals(
+            "No warnings.",
+
+            lintFiles("res/layout/useless2.xml"));
+    }
 }
diff --git a/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/layout/useless2.xml b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/layout/useless2.xml
new file mode 100644
index 0000000..a819036
--- /dev/null
+++ b/lint/libs/lint_checks/tests/src/com/android/tools/lint/checks/data/res/layout/useless2.xml
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent" >
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:orientation="vertical" >
+
+        <TabWidget
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content" />
+
+        <FrameLayout
+            android:layout_width="match_parent"
+            android:layout_height="0px"
+            android:layout_weight="1" >
+
+            <Button
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content" />
+        </FrameLayout>
+    </LinearLayout>
+
+</TabHost>