/*
* Copyright (C) 2012 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.CONSTRUCTOR_NAME;
import com.android.annotations.NonNull;
import com.android.tools.lint.detector.api.Category;
import com.android.tools.lint.detector.api.ClassContext;
import com.android.tools.lint.detector.api.Detector;
import com.android.tools.lint.detector.api.Issue;
import com.android.tools.lint.detector.api.Location;
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 org.objectweb.asm.Opcodes;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.MethodNode;
import java.io.File;
import java.util.List;
/**
* Looks for custom views that do not define the view constructors needed by UI builders
*/
public class ViewConstructorDetector extends Detector implements Detector.ClassScanner {
private static final String SIG1 =
"(Landroid/content/Context;)V"; //$NON-NLS-1$
private static final String SIG2 =
"(Landroid/content/Context;Landroid/util/AttributeSet;)V"; //$NON-NLS-1$
private static final String SIG3 =
"(Landroid/content/Context;Landroid/util/AttributeSet;I)V"; //$NON-NLS-1$
/** The main issue discovered by this detector */
public static final Issue ISSUE = Issue.create(
"ViewConstructor", //$NON-NLS-1$
"Checks that custom views define the expected constructors",
"Some layout tools (such as the Android layout editor for Eclipse) needs to " +
"find a constructor with one of the following signatures:\n" +
"* `View(Context context)`\n" +
"* `View(Context context, AttributeSet attrs)`\n" +
"* `View(Context context, AttributeSet attrs, int defStyle)`\n" +
"\n" +
"If your custom view needs to perform initialization which does not apply when " +
"used in a layout editor, you can surround the given code with a check to " +
"see if `View#isInEditMode()` is false, since that method will return `false` " +
"at runtime but true within a user interface editor.",
Category.USABILITY,
3,
Severity.WARNING,
ViewConstructorDetector.class,
Scope.CLASS_FILE_SCOPE);
/** Constructs a new {@link ViewConstructorDetector} check */
public ViewConstructorDetector() {
}
@Override
public @NonNull Speed getSpeed() {
return Speed.FAST;
}
// ---- Implements ClassScanner ----
@Override
public void checkClass(@NonNull ClassContext context, @NonNull ClassNode classNode) {
if (classNode.name.indexOf('$') != -1
&& (classNode.access & Opcodes.ACC_STATIC) == 0) {
// Ignore inner classes that aren't static: we can't create these
// anyway since we'd need the outer instance
return;
}
if (isViewClass(context, classNode)) {
checkConstructors(context, classNode);
}
}
private static boolean isViewClass(ClassContext context, ClassNode node) {
String superName = node.superName;
while (superName != null) {
if (superName.equals("android/view/View") //$NON-NLS-1$
|| superName.equals("android/view/ViewGroup") //$NON-NLS-1$
|| superName.startsWith("android/widget/") //$NON-NLS-1$
&& !((superName.endsWith("Adapter") //$NON-NLS-1$
|| superName.endsWith("Controller") //$NON-NLS-1$
|| superName.endsWith("Service") //$NON-NLS-1$
|| superName.endsWith("Provider") //$NON-NLS-1$
|| superName.endsWith("Filter")))) { //$NON-NLS-1$
return true;
}
superName = context.getDriver().getSuperClass(superName);
}
return false;
}
private void checkConstructors(ClassContext context, ClassNode classNode) {
// Look through constructors
@SuppressWarnings("rawtypes")
List methods = classNode.methods;
for (Object methodObject : methods) {
MethodNode method = (MethodNode) methodObject;
if (method.name.equals(CONSTRUCTOR_NAME)) {
String desc = method.desc;
if (desc.equals(SIG1) || desc.equals(SIG2) || desc.equals(SIG3)) {
return;
}
}
}
// If we get this far, none of the expected constructors were found.
// Use location of one of the constructors?
String message = String.format(
"Custom view %1$s is missing constructor used by tools: " +
"(Context) or (Context,AttributeSet) or (Context,AttributeSet,int)",
classNode.name);
File sourceFile = context.getSourceFile();
Location location = Location.create(sourceFile != null
? sourceFile : context.file);
context.report(ISSUE, location, message, null /*data*/);
}
}