com.android.tools.lint.checks.StateListDetector Maven / Gradle / Ivy
/*
* 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 com.android.annotations.NonNull;
import com.android.resources.ResourceFolderType;
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.LintUtils;
import com.android.tools.lint.detector.api.Location;
import com.android.tools.lint.detector.api.ResourceXmlDetector;
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.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* Checks for unreachable states in an Android state list definition
*/
public class StateListDetector extends ResourceXmlDetector {
/** The main issue discovered by this detector */
public static final Issue ISSUE = Issue.create(
"StateListReachable", //$NON-NLS-1$
"Unreachable state in a ``",
"In a selector, only the last child in the state list should omit a " +
"state qualifier. If not, all subsequent items in the list will be ignored " +
"since the given item will match all.",
Category.CORRECTNESS,
5,
Severity.WARNING,
new Implementation(
StateListDetector.class,
Scope.RESOURCE_FILE_SCOPE));
private static final String STATE_PREFIX = "state_"; //$NON-NLS-1$
/** Constructs a new {@link StateListDetector} */
public StateListDetector() {
}
@Override
public boolean appliesTo(@NonNull ResourceFolderType folderType) {
return folderType == ResourceFolderType.DRAWABLE;
}
@NonNull
@Override
public Speed getSpeed() {
return Speed.FAST;
}
@Override
public void visitDocument(@NonNull XmlContext context, @NonNull Document document) {
// TODO: Look for views that don't specify
// Display the error token somewhere so it can be suppressed
// Emit warning at the end "run with --help to learn how to suppress types of errors/checks";
// ("...and this message.")
Element root = document.getDocumentElement();
if (root != null && root.getTagName().equals("selector")) { //$NON-NLS-1$
List children = LintUtils.getChildren(root);
Map> states =
new HashMap>(children.size());
for (int i = 0; i < children.size(); i++) {
Element child = children.get(i);
NamedNodeMap attributes = child.getAttributes();
Set stateNames = new HashSet(attributes.getLength());
states.put(child, stateNames);
for (int j = 0; j < attributes.getLength(); j++) {
Attr attribute = (Attr) attributes.item(j);
String name = attribute.getLocalName();
if (name == null) {
continue;
}
if (name.startsWith(STATE_PREFIX)) {
stateNames.add(name + '=' + attribute.getValue());
} else {
String namespaceUri = attribute.getNamespaceURI();
if (namespaceUri != null && !namespaceUri.isEmpty() &&
!ANDROID_URI.equals(namespaceUri)) {
// There is a custom attribute on this item.
// This could be a state, see
// http://code.google.com/p/android/issues/detail?id=22339
// so don't flag this one.
stateNames.add(attribute.getName() + '=' + attribute.getValue());
}
}
}
}
// See if for each state, any subsequent state fully contains all the same
// state requirements
for (int i = 0; i < children.size() - 1; i++) {
Element prev = children.get(i);
Set prevStates = states.get(prev);
assert prevStates != null : prev;
for (int j = i + 1; j < children.size(); j++) {
Element current = children.get(j);
Set currentStates = states.get(current);
assert currentStates != null : current;
if (currentStates.containsAll(prevStates)) {
Location location = context.getLocation(current);
Location secondary = context.getLocation(prev);
secondary.setMessage("Earlier item which masks item");
location.setSecondary(secondary);
context.report(ISSUE, current, location, String.format(
"This item is unreachable because a previous item (item #%1$d) is a more general match than this one",
i + 1));
// Don't keep reporting errors for all the remaining cases in this file
return;
}
}
}
}
}
}