| /* |
| * Copyright (C) 2011 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.tools.lint.checks; |
| |
| import static com.android.SdkConstants.GRID_VIEW; |
| import static com.android.SdkConstants.HORIZONTAL_SCROLL_VIEW; |
| import static com.android.SdkConstants.LIST_VIEW; |
| import static com.android.SdkConstants.REQUEST_FOCUS; |
| import static com.android.SdkConstants.SCROLL_VIEW; |
| |
| import com.android.annotations.NonNull; |
| import com.android.tools.lint.detector.api.Category; |
| import com.android.tools.lint.detector.api.Implementation; |
| import com.android.tools.lint.detector.api.Issue; |
| import com.android.tools.lint.detector.api.LayoutDetector; |
| import com.android.tools.lint.detector.api.LintUtils; |
| import com.android.tools.lint.detector.api.Scope; |
| import com.android.tools.lint.detector.api.Severity; |
| import com.android.tools.lint.detector.api.Speed; |
| import com.android.tools.lint.detector.api.XmlContext; |
| |
| import org.w3c.dom.Element; |
| import org.w3c.dom.Node; |
| import org.w3c.dom.NodeList; |
| |
| import java.util.Arrays; |
| import java.util.Collection; |
| |
| /** |
| * Check which makes sure that views have the expected number of declared |
| * children (e.g. at most one in ScrollViews and none in AdapterViews) |
| */ |
| public class ChildCountDetector extends LayoutDetector { |
| |
| private static final Implementation IMPLEMENTATION = new Implementation( |
| ChildCountDetector.class, |
| Scope.RESOURCE_FILE_SCOPE); |
| |
| /** The main issue discovered by this detector */ |
| public static final Issue SCROLLVIEW_ISSUE = Issue.create( |
| "ScrollViewCount", //$NON-NLS-1$ |
| "ScrollViews can have only one child", |
| "ScrollViews can only have one child widget. If you want more children, wrap them " + |
| "in a container layout.", |
| Category.CORRECTNESS, |
| 8, |
| Severity.WARNING, |
| IMPLEMENTATION); |
| |
| /** The main issue discovered by this detector */ |
| public static final Issue ADAPTER_VIEW_ISSUE = Issue.create( |
| "AdapterViewChildren", //$NON-NLS-1$ |
| "AdapterViews cannot have children in XML", |
| "AdapterViews such as ListViews must be configured with data from Java code, " + |
| "such as a ListAdapter.", |
| Category.CORRECTNESS, |
| 10, |
| Severity.WARNING, |
| IMPLEMENTATION) |
| .addMoreInfo( |
| "http://developer.android.com/reference/android/widget/AdapterView.html"); //$NON-NLS-1$ |
| |
| /** Constructs a new {@link ChildCountDetector} */ |
| public ChildCountDetector() { |
| } |
| |
| @NonNull |
| @Override |
| public Speed getSpeed() { |
| return Speed.FAST; |
| } |
| |
| @Override |
| public Collection<String> getApplicableElements() { |
| return Arrays.asList( |
| SCROLL_VIEW, |
| HORIZONTAL_SCROLL_VIEW, |
| LIST_VIEW, |
| GRID_VIEW |
| // TODO: Shouldn't Spinner be in this list too? (Was not there in layoutopt) |
| ); |
| } |
| |
| @Override |
| public void visitElement(@NonNull XmlContext context, @NonNull Element element) { |
| int childCount = LintUtils.getChildCount(element); |
| String tagName = element.getTagName(); |
| if (tagName.equals(SCROLL_VIEW) || tagName.equals(HORIZONTAL_SCROLL_VIEW)) { |
| if (childCount > 1 && getAccurateChildCount(element) > 1) { |
| context.report(SCROLLVIEW_ISSUE, element, |
| context.getLocation(element), "A scroll view can have only one child"); |
| } |
| } else { |
| // Adapter view |
| if (childCount > 0 && getAccurateChildCount(element) > 0) { |
| context.report(ADAPTER_VIEW_ISSUE, element, |
| context.getLocation(element), |
| "A list/grid should have no children declared in XML"); |
| } |
| } |
| } |
| |
| /** Counts the number of children, but skips certain tags like {@code <requestFocus>} */ |
| private static int getAccurateChildCount(Element element) { |
| NodeList childNodes = element.getChildNodes(); |
| int childCount = 0; |
| for (int i = 0, n = childNodes.getLength(); i < n; i++) { |
| Node child = childNodes.item(i); |
| if (child.getNodeType() == Node.ELEMENT_NODE && |
| !REQUEST_FOCUS.equals(child.getNodeName())) { |
| childCount++; |
| } |
| } |
| |
| return childCount; |
| } |
| } |