构造函数中注入次数的Lint规则

Question

我正试图在我的Android代码中创建一个Lint规则，以检查构造函数中的注入数，因此，如果我超过了视图模型的某个数字，我将提出一个lint警告。

我知道我必须在Lint检测器中实现一个UastScanner，但是我迷路了，因为我找不到好的文档。其他人做过这样的事吗？或者我在哪里能找到好的脱眼方法呢？

谢谢!

Answer 1

*备注-阅读编辑的解决方案的全部答案。*

我能够像这样编写UAST转换：

public class NumberOfDependenciesInjectedDetector extends Detector implements Detector.UastScanner {

    private static final int NUMBER_OF_INJECTIONS_ALLOWED = 5;
    private static final Class<? extends Detector> DETECTOR = NumberOfDependenciesInjectedDetector.class;
    private static final EnumSet<Scope> SCOPE = Scope.JAVA_FILE_SCOPE;
    private static final Implementation IMPLEMENTATION = new Implementation(DETECTOR, SCOPE);

    public static final Issue ISSUE = Issue.create(
            "NumberOfDependenciesInjected",
            "Limit number of injections in a class via constructor",
            "A longer description here",
            Category.CORRECTNESS,
            10,
            Severity.ERROR,
            IMPLEMENTATION
    );

    @Override
    public List<Class<? extends UElement>> getApplicableUastTypes() {
        return Collections.<Class<? extends UElement>>singletonList(UClass.class);
    }

    @Override
    public UElementHandler createUastHandler(JavaContext context) {
        return new ConstructorVisitor(context);
    }

    private static class ConstructorVisitor extends UElementHandler {

        private JavaContext javaContext;

        private ConstructorVisitor(JavaContext javaContext) {
            this.javaContext = javaContext;
        }

        @Override
        public void visitClass(UClass clazz){
            UMethod[] methods = clazz.getMethods();

            for(UMethod method : methods){
                if(!method.isConstructor()) continue;

                if (method.getParameterList().getParametersCount() > NUMBER_OF_INJECTIONS_ALLOWED) {
                    javaContext.report(ISSUE, method, javaContext.getLocation(method), "Injections exceed allowed value of " + NUMBER_OF_INJECTIONS_ALLOWED);
                }
            }
        }
    }
}

不过，似乎这还没有找到Kotlin源文件..。非常令人困惑。

编辑: 12/19/17 -固定

问题有两方面：

1) Psi方法确实有一种隐藏的用法，它阻碍了检查的工作。visitClass方法不应该使用getParameterList()，而应该使用getUastParameters()。以上客舱改为：

@Override
public void visitClass(UClass clazz){
    UMethod[] methods = clazz.getMethods();

    for(UMethod method : methods){
        if(!method.isConstructor()) continue;

        if (method.getUastParameters().size() > NUMBER_OF_INJECTIONS_ALLOWED) {
            javaContext.report(ISSUE, clazz, javaContext.getLocation(method), "Injections exceed allowed value of " + NUMBER_OF_INJECTIONS_ALLOWED);
        }
    }
}

2)在直接在lint组上与托尔·诺拜交谈后，他指出，AndroidStudio3.0实际上并不适用于kotlin，因此不能像这里所描述的那样工作。升级到AndroidStudio3.1Canary并运行linter产生了预期的报告。

Answer 2

因此，我能够使用JavaScanner找到解决方案，但还没有找到任何使用UastScanner的解决方案(这正是我想要使用的，因为我们也有Kotlin类)：

public class NumberOfDependenciesInjectedDetector extends Detector implements Detector.JavaScanner {

    private static final int NUMBER_OF_INJECTIONS_ALLOWED = 5;
    private static final Class<? extends Detector> DETECTOR = NumberOfDependenciesInjectedDetector.class;
    private static final EnumSet<Scope> SCOPE = Scope.JAVA_FILE_SCOPE;
    private static final Implementation IMPLEMENTATION = new Implementation(DETECTOR, SCOPE);

    public static final Issue ISSUE = Issue.create(
            "NumberOfDependenciesInjected",
            "Limit number of injections in a class via constructor",
            "A longer description here",
            Category.CORRECTNESS,
            10,
            Severity.ERROR,
            IMPLEMENTATION
    );

    @Override
    public boolean appliesTo(Context context, File file) {
        return true;
    }

    @Override
    public Speed getSpeed(Issue issue) {
        return Speed.FAST;
    }

    @Override
    public List<Class<? extends Node>> getApplicableNodeTypes() {
        return Collections.<Class<? extends Node>>singletonList(ConstructorDeclaration.class);
    }

    @Override
    public AstVisitor createJavaVisitor(JavaContext context) {
        return new ConstructorVisitor(context);
    }

    private static class ConstructorVisitor extends ForwardingAstVisitor {

        private JavaContext javaContext;

        private ConstructorVisitor(JavaContext javaContext) {
            this.javaContext = javaContext;
        }

        @Override
        public boolean visitConstructorDeclaration(ConstructorDeclaration node) {
            if (node.astParameters().size() > NUMBER_OF_INJECTIONS_ALLOWED) {
                javaContext.report(ISSUE, node, javaContext.getLocation(node), "My message goes here");
                return true;
            }
            return false;
        }
    }
}