Java tutorial
/* * 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.ANDROID_URI; import static com.android.SdkConstants.ATTR_ID; import static com.android.SdkConstants.ATTR_LAYOUT_RESOURCE_PREFIX; import static com.android.SdkConstants.ATTR_NAME; import static com.android.SdkConstants.ATTR_TYPE; import static com.android.SdkConstants.FD_RES_VALUES; import static com.android.SdkConstants.ID_PREFIX; import static com.android.SdkConstants.NEW_ID_PREFIX; import static com.android.SdkConstants.RELATIVE_LAYOUT; import static com.android.SdkConstants.TAG_ITEM; import static com.android.SdkConstants.VALUE_ID; import static com.android.tools.lint.detector.api.LintUtils.editDistance; import static com.android.tools.lint.detector.api.LintUtils.getChildren; import static com.android.tools.lint.detector.api.LintUtils.isSameResourceFile; import static com.android.tools.lint.detector.api.LintUtils.stripIdPrefix; import com.android.annotations.NonNull; import com.android.annotations.Nullable; import com.android.ide.common.res2.AbstractResourceRepository; import com.android.ide.common.res2.ResourceFile; import com.android.ide.common.res2.ResourceItem; import com.android.resources.ResourceFolderType; import com.android.resources.ResourceType; import com.android.tools.lint.client.api.LintClient; import com.android.tools.lint.detector.api.Category; import com.android.tools.lint.detector.api.Context; 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.Location; import com.android.tools.lint.detector.api.Location.Handle; 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 com.android.utils.Pair; import com.google.common.base.Joiner; import com.google.common.collect.ArrayListMultimap; import com.google.common.collect.Multimap; import com.google.common.collect.Sets; import org.w3c.dom.Attr; import org.w3c.dom.Element; import org.w3c.dom.NamedNodeMap; import org.w3c.dom.Node; import java.io.File; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.HashSet; import java.util.List; import java.util.Set; /** * Checks for duplicate ids within a layout and within an included layout */ public class WrongIdDetector extends LayoutDetector { private static final Implementation IMPLEMENTATION = new Implementation(WrongIdDetector.class, Scope.RESOURCE_FILE_SCOPE); /** Ids bound to widgets in any of the layout files */ private final Set<String> mGlobalIds = new HashSet<String>(100); /** Ids bound to widgets in the current layout file */ private Set<String> mFileIds; /** Ids declared in a value's file, e.g. {@code <item type="id" name="foo"/>} */ private Set<String> mDeclaredIds; /** * Location handles for the various id references that were not found as * defined in the same layout, to be checked after the whole project has * been scanned */ private List<Pair<String, Location.Handle>> mHandles; /** List of RelativeLayout elements in the current layout */ private List<Element> mRelativeLayouts; /** Reference to an unknown id */ @SuppressWarnings("unchecked") public static final Issue UNKNOWN_ID = Issue.create("UnknownId", //$NON-NLS-1$ "Reference to an unknown id", "The `@+id/` syntax refers to an existing id, or creates a new one if it has " + "not already been defined elsewhere. However, this means that if you have a " + "typo in your reference, or if the referred view no longer exists, you do not " + "get a warning since the id will be created on demand. This check catches " + "errors where you have renamed an id without updating all of the references to " + "it.", Category.CORRECTNESS, 8, Severity.FATAL, new Implementation(WrongIdDetector.class, Scope.ALL_RESOURCES_SCOPE, Scope.RESOURCE_FILE_SCOPE)); /** Reference to an id that is not a sibling */ public static final Issue NOT_SIBLING = Issue.create("NotSibling", //$NON-NLS-1$ "RelativeLayout Invalid Constraints", "Layout constraints in a given `RelativeLayout` should reference other views " + "within the same relative layout (but not itself!)", Category.CORRECTNESS, 6, Severity.FATAL, IMPLEMENTATION); /** An ID declaration which is not valid */ public static final Issue INVALID = Issue.create("InvalidId", //$NON-NLS-1$ "Invalid ID declaration", "An id definition *must* be of the form `@+id/yourname`. The tools have not " + "rejected strings of the form `@+foo/bar` in the past, but that was an error, " + "and could lead to tricky errors because of the way the id integers are assigned.\n" + "\n" + "If you really want to have different \"scopes\" for your id's, use prefixes " + "instead, such as `login_button1` and `login_button2`.", Category.CORRECTNESS, 6, Severity.FATAL, IMPLEMENTATION); /** Reference to an id that is not in the current layout */ public static final Issue UNKNOWN_ID_LAYOUT = Issue.create("UnknownIdInLayout", //$NON-NLS-1$ "Reference to an id that is not in the current layout", "The `@+id/` syntax refers to an existing id, or creates a new one if it has " + "not already been defined elsewhere. However, this means that if you have a " + "typo in your reference, or if the referred view no longer exists, you do not " + "get a warning since the id will be created on demand.\n" + "\n" + "This is sometimes intentional, for example where you are referring to a view " + "which is provided in a different layout via an include. However, it is usually " + "an accident where you have a typo or you have renamed a view without updating " + "all the references to it.", Category.CORRECTNESS, 5, Severity.WARNING, new Implementation(WrongIdDetector.class, Scope.RESOURCE_FILE_SCOPE)); /** Constructs a duplicate id check */ public WrongIdDetector() { } @Override public boolean appliesTo(@NonNull ResourceFolderType folderType) { return folderType == ResourceFolderType.LAYOUT || folderType == ResourceFolderType.VALUES; } @NonNull @Override public Speed getSpeed() { return Speed.FAST; } @Override public Collection<String> getApplicableAttributes() { return Collections.singletonList(ATTR_ID); } @Override public Collection<String> getApplicableElements() { return Arrays.asList(RELATIVE_LAYOUT, TAG_ITEM); } @Override public void beforeCheckFile(@NonNull Context context) { mFileIds = new HashSet<String>(); mRelativeLayouts = null; } @Override public void afterCheckFile(@NonNull Context context) { if (mRelativeLayouts != null) { if (!context.getProject().getReportIssues()) { // If this is a library project not being analyzed, ignore it return; } for (Element layout : mRelativeLayouts) { List<Element> children = getChildren(layout); Set<String> ids = Sets.newHashSetWithExpectedSize(children.size()); for (Element child : children) { String id = child.getAttributeNS(ANDROID_URI, ATTR_ID); if (id != null && !id.isEmpty()) { ids.add(id); } } for (Element element : children) { String selfId = stripIdPrefix(element.getAttributeNS(ANDROID_URI, ATTR_ID)); NamedNodeMap attributes = element.getAttributes(); for (int i = 0, n = attributes.getLength(); i < n; i++) { Attr attr = (Attr) attributes.item(i); String value = attr.getValue(); if ((value.startsWith(NEW_ID_PREFIX) || value.startsWith(ID_PREFIX)) && ANDROID_URI.equals(attr.getNamespaceURI()) && attr.getLocalName().startsWith(ATTR_LAYOUT_RESOURCE_PREFIX)) { if (!idDefined(mFileIds, value)) { // Stash a reference to this id and location such that // we can check after the *whole* layout has been processed, // since it's too early to conclude here that the id does // not exist (you are allowed to have forward references) XmlContext xmlContext = (XmlContext) context; Handle handle = xmlContext.createLocationHandle(attr); handle.setClientData(attr); if (mHandles == null) { mHandles = new ArrayList<Pair<String, Handle>>(); } mHandles.add(Pair.of(value, handle)); } else { // Check siblings. TODO: Look for cycles! if (ids.contains(value)) { // Make sure it's not pointing to self if (!ATTR_ID.equals(attr.getLocalName()) && !selfId.isEmpty() && value.endsWith(selfId) && stripIdPrefix(value).equals(selfId)) { XmlContext xmlContext = (XmlContext) context; String message = String.format( "Cannot be relative to self: id=%1$s, %2$s=%3$s", selfId, attr.getLocalName(), selfId); Location location = xmlContext.getLocation(attr); xmlContext.report(NOT_SIBLING, attr, location, message); } continue; } if (value.startsWith(NEW_ID_PREFIX)) { if (ids.contains(ID_PREFIX + stripIdPrefix(value))) { continue; } } else { assert value.startsWith(ID_PREFIX) : value; if (ids.contains(NEW_ID_PREFIX + stripIdPrefix(value))) { continue; } } if (context.isEnabled(NOT_SIBLING)) { XmlContext xmlContext = (XmlContext) context; String message = String .format("`%1$s` is not a sibling in the same `RelativeLayout`", value); Location location = xmlContext.getLocation(attr); xmlContext.report(NOT_SIBLING, attr, location, message); } } } } } } } mFileIds = null; if (!context.getScope().contains(Scope.ALL_RESOURCE_FILES)) { checkHandles(context); } } @Override public void afterCheckProject(@NonNull Context context) { if (context.getScope().contains(Scope.ALL_RESOURCE_FILES)) { checkHandles(context); } } private void checkHandles(@NonNull Context context) { if (mHandles != null) { boolean checkSameLayout = context.isEnabled(UNKNOWN_ID_LAYOUT); boolean checkExists = context.isEnabled(UNKNOWN_ID); boolean projectScope = context.getScope().contains(Scope.ALL_RESOURCE_FILES); for (Pair<String, Handle> pair : mHandles) { String id = pair.getFirst(); boolean isBound = projectScope ? idDefined(mGlobalIds, id) : idDefined(context, id, context.file); LintClient client = context.getClient(); if (!isBound && checkExists && (projectScope || client.supportsProjectResources())) { Handle handle = pair.getSecond(); boolean isDeclared = idDefined(mDeclaredIds, id); id = stripIdPrefix(id); String suggestionMessage; Set<String> spellingDictionary = mGlobalIds; if (!projectScope && client.supportsProjectResources()) { AbstractResourceRepository resources = client.getProjectResources(context.getProject(), true); if (resources != null) { spellingDictionary = Sets.newHashSet(resources.getItemsOfType(ResourceType.ID)); spellingDictionary.remove(id); } } List<String> suggestions = getSpellingSuggestions(id, spellingDictionary); if (suggestions.size() > 1) { suggestionMessage = String.format(" Did you mean one of {%2$s} ?", id, Joiner.on(", ").join(suggestions)); } else if (!suggestions.isEmpty()) { suggestionMessage = String.format(" Did you mean %2$s ?", id, suggestions.get(0)); } else { suggestionMessage = ""; } String message; if (isDeclared) { message = String.format("The id \"`%1$s`\" is defined but not assigned to any views.%2$s", id, suggestionMessage); } else { message = String.format("The id \"`%1$s`\" is not defined anywhere.%2$s", id, suggestionMessage); } report(context, UNKNOWN_ID, handle, message); } else if (checkSameLayout && (!projectScope || isBound) && id.startsWith(NEW_ID_PREFIX)) { // The id was defined, but in a different layout. Usually not intentional // (might be referring to a random other view that happens to have the same // name.) Handle handle = pair.getSecond(); report(context, UNKNOWN_ID_LAYOUT, handle, String.format( "The id \"`%1$s`\" is not referring to any views in this layout", stripIdPrefix(id))); } } } } private static void report(Context context, Issue issue, Handle handle, String message) { Location location = handle.resolve(); Object clientData = handle.getClientData(); if (clientData instanceof Node) { if (context.getDriver().isSuppressed(null, issue, (Node) clientData)) { return; } } context.report(issue, location, message); } @Override public void visitElement(@NonNull XmlContext context, @NonNull Element element) { if (element.getTagName().equals(RELATIVE_LAYOUT)) { if (mRelativeLayouts == null) { mRelativeLayouts = new ArrayList<Element>(); } mRelativeLayouts.add(element); } else { assert element.getTagName().equals(TAG_ITEM); String type = element.getAttribute(ATTR_TYPE); if (VALUE_ID.equals(type)) { String name = element.getAttribute(ATTR_NAME); if (!name.isEmpty()) { if (mDeclaredIds == null) { mDeclaredIds = Sets.newHashSet(); } mDeclaredIds.add(ID_PREFIX + name); } } } } @Override public void visitAttribute(@NonNull XmlContext context, @NonNull Attr attribute) { assert attribute.getName().equals(ATTR_ID) || attribute.getLocalName().equals(ATTR_ID); String id = attribute.getValue(); mFileIds.add(id); mGlobalIds.add(id); if (id.equals(NEW_ID_PREFIX) || id.equals(ID_PREFIX) || "@+id".equals(ID_PREFIX)) { String message = "Invalid id: missing value"; context.report(INVALID, attribute, context.getLocation(attribute), message); } else if (id.startsWith("@+") && !id.startsWith(NEW_ID_PREFIX) //$NON-NLS-1$ && !id.startsWith("@+android:id/") //$NON-NLS-1$ || id.startsWith(NEW_ID_PREFIX) && id.indexOf('/', NEW_ID_PREFIX.length()) != -1) { int nameStart = id.startsWith(NEW_ID_PREFIX) ? NEW_ID_PREFIX.length() : 2; String suggested = NEW_ID_PREFIX + id.substring(nameStart).replace('/', '_'); String message = String.format("ID definitions *must* be of the form `@+id/name`; try using `%1$s`", suggested); context.report(INVALID, attribute, context.getLocation(attribute), message); } } private static boolean idDefined(Set<String> ids, String id) { if (ids == null) { return false; } boolean definedLocally = ids.contains(id); if (!definedLocally) { if (id.startsWith(NEW_ID_PREFIX)) { definedLocally = ids.contains(ID_PREFIX + id.substring(NEW_ID_PREFIX.length())); } else if (id.startsWith(ID_PREFIX)) { definedLocally = ids.contains(NEW_ID_PREFIX + id.substring(ID_PREFIX.length())); } } return definedLocally; } private boolean idDefined(@NonNull Context context, @NonNull String id, @Nullable File notIn) { AbstractResourceRepository resources = context.getClient().getProjectResources(context.getProject(), true); if (resources != null) { List<ResourceItem> items = resources.getResourceItem(ResourceType.ID, stripIdPrefix(id)); if (items == null || items.isEmpty()) { return false; } for (ResourceItem item : items) { ResourceFile source = item.getSource(); if (source != null) { File file = source.getFile(); if (file.getParentFile().getName().startsWith(FD_RES_VALUES)) { if (mDeclaredIds == null) { mDeclaredIds = Sets.newHashSet(); } mDeclaredIds.add(id); continue; } // Ignore definitions in the given file. This is used to ignore // matches in the same file as the reference, since the reference // is often expressed as a definition if (!isSameResourceFile(file, notIn)) { return true; } } } } return false; } private static List<String> getSpellingSuggestions(String id, Collection<String> ids) { int maxDistance = id.length() >= 4 ? 2 : 1; // Look for typos and try to match with custom views and android views Multimap<Integer, String> matches = ArrayListMultimap.create(2, 10); int count = 0; if (!ids.isEmpty()) { for (String matchWith : ids) { matchWith = stripIdPrefix(matchWith); if (Math.abs(id.length() - matchWith.length()) > maxDistance) { // The string lengths differ more than the allowed edit distance; // no point in even attempting to compute the edit distance (requires // O(n*m) storage and O(n*m) speed, where n and m are the string lengths) continue; } int distance = editDistance(id, matchWith); if (distance <= maxDistance) { matches.put(distance, matchWith); } if (count++ > 100) { // Make sure that for huge projects we don't completely grind to a halt break; } } } for (int i = 0; i < maxDistance; i++) { Collection<String> strings = matches.get(i); if (strings != null && !strings.isEmpty()) { List<String> suggestions = new ArrayList<String>(strings); Collections.sort(suggestions); return suggestions; } } return Collections.emptyList(); } }