Adding a link to Setting activity for the Home app

The link is only visible if there is a default home add and it
implements a settings activity

Test: make -j20 RunSettingsRoboTests
Change-Id: Iac5d0ebd561bed2e5b2f84236cdb728362ed8663

res/xml/app_default_settings.xml

@@ -33,7 +33,7 @@
         <extra android:name="for_work" android:value="false" />
     </com.android.settings.widget.AppPreference>
 
-    <com.android.settings.widget.AppPreference
+    <com.android.settings.widget.GearPreference
         android:key="default_home"
         android:title="@string/home_app"
         android:fragment="com.android.settings.applications.defaultapps.DefaultHomePicker"

src/com/android/settings/applications/defaultapps/DefaultHomePreferenceController.java

@@ -63,7 +63,7 @@ public class DefaultHomePreferenceController extends DefaultAppPreferenceControl
         if (currentDefaultHome != null) {
             return new DefaultAppInfo(mContext, mPackageManager, mUserId, currentDefaultHome);
         }
-        final ActivityInfo onlyAppInfo = getOnlyAppInfo();
+        final ActivityInfo onlyAppInfo = getOnlyAppInfo(homeActivities);
         if (onlyAppInfo != null) {
             return new DefaultAppInfo(mContext, mPackageManager, mUserId,
                     onlyAppInfo.getComponentName());
@@ -71,8 +71,7 @@ public class DefaultHomePreferenceController extends DefaultAppPreferenceControl
         return null;
     }
 
-    private ActivityInfo getOnlyAppInfo() {
+    private ActivityInfo getOnlyAppInfo(List<ResolveInfo> homeActivities) {
-        final List<ResolveInfo> homeActivities = new ArrayList<>();
         final List<ActivityInfo> appLabels = new ArrayList<>();
 
         mPackageManager.getHomeActivities(homeActivities);
@@ -88,6 +87,23 @@ public class DefaultHomePreferenceController extends DefaultAppPreferenceControl
                 : null;
     }
 
+    @Override
+    protected Intent getSettingIntent(DefaultAppInfo info) {
+        final String packageName;
+        if (info.componentName != null) {
+            packageName = info.componentName.getPackageName();
+        } else if (info.packageItemInfo != null) {
+            packageName = info.packageItemInfo.packageName;
+        } else {
+            return null;
+        }
+
+        Intent intent = new Intent(Intent.ACTION_APPLICATION_PREFERENCES)
+                .setPackage(packageName)
+                .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+        return mPackageManager.queryIntentActivities(intent, 0).size() == 1 ? intent : null;
+    }
+
     public static boolean hasHomePreference(String pkg, Context context) {
         ArrayList<ResolveInfo> homeActivities = new ArrayList<>();
         PackageManager pm = context.getPackageManager();

tests/robotests/src/com/android/settings/applications/defaultapps/DefaultHomePreferenceControllerTest.java

@@ -17,6 +17,9 @@
 package com.android.settings.applications.defaultapps;
 
 import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Matchers.anyList;
 import static org.mockito.Mockito.atLeastOnce;
 import static org.mockito.Mockito.mock;
@@ -26,6 +29,8 @@ import static org.mockito.Mockito.when;
 
 import android.content.ComponentName;
 import android.content.Context;
+import android.content.Intent;
+import android.content.pm.ResolveInfo;
 import android.os.UserManager;
 import android.support.v7.preference.Preference;
 
@@ -42,6 +47,9 @@ import org.mockito.MockitoAnnotations;
 import org.robolectric.annotation.Config;
 import org.robolectric.util.ReflectionHelpers;
 
+import java.util.Arrays;
+
+
 @RunWith(SettingsRobolectricTestRunner.class)
 @Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
 public class DefaultHomePreferenceControllerTest {
@@ -112,4 +120,32 @@ public class DefaultHomePreferenceControllerTest {
         assertThat(DefaultHomePreferenceController.isHomeDefault(pkgName, mPackageManager))
                 .isFalse();
     }
+
+    @Test
+    public void testGetSettingIntent_homeHasNoSetting_shouldNotReturnSettingIntent() {
+        when(mPackageManager.getHomeActivities(anyList())).thenReturn(
+                new ComponentName("test.pkg", "class"));
+        assertThat(mController.getSettingIntent(mController.getDefaultAppInfo())).isNull();
+    }
+
+    @Test
+    public void testGetSettingIntent_homeHasOneSetting_shouldReturnSettingIntent() {
+        when(mPackageManager.getHomeActivities(anyList())).thenReturn(
+                new ComponentName("test.pkg", "class"));
+        when(mPackageManager.queryIntentActivities(any(), eq(0))).thenReturn(
+                Arrays.asList(mock(ResolveInfo.class)));
+
+        Intent intent = mController.getSettingIntent(mController.getDefaultAppInfo());
+        assertThat(intent).isNotNull();
+        assertThat(intent.getPackage()).isEqualTo("test.pkg");
+    }
+
+    @Test
+    public void testGetSettingIntent_homeHasMultipleSettings_shouldNotReturnSettingIntent() {
+        when(mPackageManager.getHomeActivities(anyList())).thenReturn(
+                new ComponentName("test.pkg", "class"));
+        when(mPackageManager.queryIntentActivities(any(), eq(0))).thenReturn(
+                Arrays.asList(mock(ResolveInfo.class), mock(ResolveInfo.class)));
+        assertThat(mController.getSettingIntent(mController.getDefaultAppInfo())).isNull();
+    }
 }