Javassist in Android(一) 过滤onClic

通过解析所有的类，过滤出onClick方法用来注入我们的事件统计代码。 没有逻辑性的问题，就直接上代码了。

由于Javassist的封装比较复杂，首先我要定义两个实体，存放我解析出来需要用到的Method属性。

public class IMethod {
    
    private String name;
    private List<IMethodParam> params = new ArrayList<>();
    private String returnType;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    
    public List<IMethodParam> getParams() {
        return params;
    }
    public void setParams(List<IMethodParam> params) {
        this.params = params;
    }
    public String getReturnType() {
        return returnType;
    }
    public void setReturnType(String returnType) {
        this.returnType = returnType;
    }
    
    public void addParam(IMethodParam param) {
        if(param != null){
            params.add(param);
        }
    }
}


public class IMethodParam {
    private String type;//the typename of param, example:android.view.View
    private String name;//the name of param, example:v
    
    
    public IMethodParam() {
        super();
    }
    public IMethodParam(String type, String name) {
        super();
        this.type = type;
        this.name = name;
    }
    public String getType() {
        return type;
    }
    public void setType(String type) {
        this.type = type;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    
    @Override
    public boolean equals(Object obj) {
        if (obj instanceof IMethodParam) {
            IMethodParam param = (IMethodParam) obj;
            return (type != null && name != null//
                    && param != null//
                    && param.getType() != null//
                    && param.getName() != null//
                    && type.equals(param.getType())//
                    && name.equals(param.getName()));//
        }
        
        return super.equals(obj);
    }
    
    @Override
    public int hashCode() {
        if(type != null && name != null)
            return (type + name).hashCode();
        return super.hashCode();
    }

}

接着我们要解析Mehod,我们主要需要方法名，参数类型的名称，参数的名称以及返回值的类型名称

public static IMethod parse(CtMethod method){
        if(method != null){
            IMethod iMethod = new IMethod();
            iMethod.setName(method.getName());
            
            /***
             * 获取参数的类型和值
             */
            try {
                CtClass[] parameterTypes = method.getParameterTypes();
                if(parameterTypes != null && parameterTypes.length > 0){
                    int len = parameterTypes.length;
                    String[] paramNames = getMethodParamNames(method);
                    if(paramNames != null && paramNames.length >= len){
                        for (int i = 0; i < parameterTypes.length; i++) {
                            IMethodParam param = new IMethodParam();
                            param.setType(parameterTypes[i].getName());
                            param.setName(paramNames[i]);
                            
                            iMethod.addParam(param);
                        }
                    }
                }
                
                CtClass returnType = method.getReturnType();
                if(returnType != null){
                    iMethod.setReturnType(returnType.getName());
                }
                
            } catch (NotFoundException e) {
                e.printStackTrace();
            }
            
            return iMethod;
        }
        return null;
    }


public static String[] getMethodParamNames(CtMethod cm) {
        MethodInfo methodInfo = cm.getMethodInfo();
        CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
        LocalVariableAttribute attr = (LocalVariableAttribute) codeAttribute
                .getAttribute(LocalVariableAttribute.tag);
        if (attr == null) {
            return null;
        }
        String[] paramNames = null;
        
        try {
            CtClass[] parameterTypes = cm.getParameterTypes();
            if(parameterTypes != null && parameterTypes.length > 0){
                paramNames = new String[parameterTypes.length];
            }
        } catch (NotFoundException e) {
            e.printStackTrace();
            return null;
        }
        int pos = Modifier.isStatic(cm.getModifiers()) ? 0 : 1;
        for (int i = 0; i < paramNames.length; i++) {
            paramNames[i] = attr.variableName(i + pos);
        }
        return paramNames;
    }

剩下的就是根据解析出来的内容来判断是否是onClick方法

public static final String ONCLICK_METHOD_NAME = "onClick";
    public static final String ONCLICK_METHOD_PARAM_TYPE = "android.view.View";
    public static final String ONCLICK_METHOD_RETURN_TYPE = "void";
    public static boolean isOnClick(IMethod method){
        if(method != null){
            String name = method.getName();
            List<IMethodParam> params = method.getParams();
            String returnType = method.getReturnType();
            if(notNul(name) && notNul(returnType) && notNul(params)){
                IMethodParam param = params.get(0);
                return ONCLICK_METHOD_NAME.equals(name)
                        && ONCLICK_METHOD_RETURN_TYPE.equals(returnType)
                        && ONCLICK_METHOD_PARAM_TYPE.equals(param.getType());
            }
        }
        return false;
    }
    
    public static boolean notNul(String s){
        return s!= null && !"".equals(s);
    }
    
    
    public static boolean notNul(List list){
        return list != null && list.size() > 0;
    }