Xposed Hook 技术深度解析：方法拦截与运行时修改的艺术

Xposed Hook 技术是 Android 系统级修改的核心，它通过在运行时拦截和修改方法调用来实现功能定制。本文将深入分析 Hook 技术的工作原理、实现方式和高级应用技巧。

Hook 技术原理

ART 虚拟机中的 Hook 机制

// Hook 原理示例 - 方法替换机制
public class HookPrincipleDemo {
    
    // 原始方法
    public String originalMethod(String input) {
        return "Original: " + input;
    }
    
    // Hook 后的方法调用流程
    public String hookedMethodFlow(String input) {
        // 1. beforeHookedMethod 执行
        String modifiedInput = beforeHook(input);
        
        // 2. 原始方法执行（可选）
        String originalResult = originalMethod(modifiedInput);
        
        // 3. afterHookedMethod 执行
        String finalResult = afterHook(originalResult);
        
        return finalResult;
    }
    
    private String beforeHook(String input) {
        System.out.println("Before hook: " + input);
        return "Modified_" + input;
    }
    
    private String afterHook(String result) {
        System.out.println("After hook: " + result);
        return result + "_Hooked";
    }
}

方法签名和参数处理

// MethodSignatureHandler.java - 方法签名处理
package com.example.xposed.hook;

import de.robv.android.xposed.XC_MethodHook;
import de.robv.android.xposed.XposedBridge;
import de.robv.android.xposed.XposedHelpers;

public class MethodSignatureHandler {
    
    // 处理不同参数类型的方法
    public static void hookMethodsWithDifferentSignatures(ClassLoader classLoader) {
        
        // 1. 无参数方法
        XposedHelpers.findAndHookMethod(
            "com.example.TargetClass",
            classLoader,
            "noParamMethod",
            new XC_MethodHook() {
                @Override
                protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                    XposedBridge.log("Hook 无参数方法");
                }
            }
        );
        
        // 2. 基本类型参数
        XposedHelpers.findAndHookMethod(
            "com.example.TargetClass",
            classLoader,
            "primitiveParamMethod",
            int.class,           // int 参数
            boolean.class,       // boolean 参数
            double.class,        // double 参数
            new XC_MethodHook() {
                @Override
                protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                    int intParam = (Integer) param.args[0];
                    boolean boolParam = (Boolean) param.args[1];
                    double doubleParam = (Double) param.args[2];
                    
                    XposedBridge.log(String.format(
                        "基本类型参数: int=%d, boolean=%b, double=%f",
                        intParam, boolParam, doubleParam
                    ));
                }
            }
        );
        
        // 3. 对象类型参数
        XposedHelpers.findAndHookMethod(
            "com.example.TargetClass",
            classLoader,
            "objectParamMethod",
            String.class,        // String 参数
            java.util.List.class, // List 参数
            new XC_MethodHook() {
                @Override
                protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                    String stringParam = (String) param.args[0];
                    java.util.List<?> listParam = (java.util.List<?>) param.args[1];
                    
                    XposedBridge.log("String 参数: " + stringParam);
                    XposedBridge.log("List 大小: " + (listParam != null ? listParam.size() : 0));
                }
            }
        );
        
        // 4. 数组参数
        XposedHelpers.findAndHookMethod(
            "com.example.TargetClass",
            classLoader,
            "arrayParamMethod",
            String[].class,      // String 数组
            int[].class,         // int 数组
            new XC_MethodHook() {
                @Override
                protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                    String[] stringArray = (String[]) param.args[0];
                    int[] intArray = (int[]) param.args[1];
                    
                    XposedBridge.log("String 数组长度: " + 
                        (stringArray != null ? stringArray.length : 0));
                    XposedBridge.log("int 数组长度: " + 
                        (intArray != null ? intArray.length : 0));
                }
            }
        );
        
        // 5. 可变参数方法
        hookVariableArgsMethod(classLoader);
    }
    
    // 处理可变参数方法
    private static void hookVariableArgsMethod(ClassLoader classLoader) {
        try {
            Class<?> targetClass = XposedHelpers.findClass("com.example.TargetClass", classLoader);
            
            // 查找可变参数方法
            java.lang.reflect.Method[] methods = targetClass.getDeclaredMethods();
            for (java.lang.reflect.Method method : methods) {
                if (method.getName().equals("varArgsMethod") && method.isVarArgs()) {
                    XposedBridge.hookMethod(method, new XC_MethodHook() {
                        @Override
                        protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                            Object[] args = param.args;
                            XposedBridge.log("可变参数方法，参数数量: " + args.length);
                            
                            for (int i = 0; i < args.length; i++) {
                                XposedBridge.log("参数[" + i + "]: " + args[i]);
                            }
                        }
                    });
                    break;
                }
            }
        } catch (Throwable t) {
            XposedBridge.log("Hook 可变参数方法失败: " + t.getMessage());
        }
    }
}

高级 Hook 技巧

动态方法查找和 Hook

// DynamicMethodHooker.java - 动态方法 Hook
package com.example.xposed.hook;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.List;

import de.robv.android.xposed.XC_MethodHook;
import de.robv.android.xposed.XposedBridge;
import de.robv.android.xposed.XposedHelpers;

public class DynamicMethodHooker {
    
    // 根据条件动态查找并 Hook 方法
    public static void hookMethodsByPattern(String className, ClassLoader classLoader, 
                                          String methodNamePattern, 
                                          Class<?> returnType) {
        try {
            Class<?> targetClass = XposedHelpers.findClass(className, classLoader);
            Method[] methods = targetClass.getDeclaredMethods();
            
            for (Method method : methods) {
                // 检查方法名模式
                if (method.getName().matches(methodNamePattern)) {
                    // 检查返回类型
                    if (returnType == null || method.getReturnType().equals(returnType)) {
                        hookMethodDynamically(method);
                    }
                }
            }
        } catch (Throwable t) {
            XposedBridge.log("动态 Hook 失败: " + t.getMessage());
        }
    }
    
    // Hook 所有公共方法
    public static void hookAllPublicMethods(String className, ClassLoader classLoader) {
        try {
            Class<?> targetClass = XposedHelpers.findClass(className, classLoader);
            Method[] methods = targetClass.getDeclaredMethods();
            
            for (Method method : methods) {
                if (Modifier.isPublic(method.getModifiers()) && 
                    !Modifier.isStatic(method.getModifiers())) {
                    
                    XposedBridge.hookMethod(method, new XC_MethodHook() {
                        @Override
                        protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                            XposedBridge.log("调用公共方法: " + method.getName());
                        }
                    });
                }
            }
        } catch (Throwable t) {
            XposedBridge.log("Hook 所有公共方法失败: " + t.getMessage());
        }
    }
    
    // 动态 Hook 单个方法
    private static void hookMethodDynamically(Method method) {
        try {
            XposedBridge.hookMethod(method, new XC_MethodHook() {
                @Override
                protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                    logMethodCall(method, param.args);
                }
                
                @Override
                protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                    logMethodResult(method, param.getResult());
                }
            });
            
            XposedBridge.log("成功 Hook 方法: " + method.getName());
        } catch (Throwable t) {
            XposedBridge.log("Hook 方法失败 " + method.getName() + ": " + t.getMessage());
        }
    }
    
    // 记录方法调用
    private static void logMethodCall(Method method, Object[] args) {
        StringBuilder sb = new StringBuilder();
        sb.append("方法调用: ").append(method.getName()).append("(");
        
        if (args != null) {
            for (int i = 0; i < args.length; i++) {
                if (i > 0) sb.append(", ");
                sb.append(formatArgument(args[i]));
            }
        }
        
        sb.append(")");
        XposedBridge.log(sb.toString());
    }
    
    // 记录方法结果
    private static void logMethodResult(Method method, Object result) {
        XposedBridge.log("方法返回: " + method.getName() + " -> " + formatArgument(result));
    }
    
    // 格式化参数显示
    private static String formatArgument(Object arg) {
        if (arg == null) {
            return "null";
        } else if (arg instanceof String) {
            return "\"" + arg + "\"";
        } else if (arg instanceof Number || arg instanceof Boolean) {
            return arg.toString();
        } else if (arg.getClass().isArray()) {
            return "[Array:" + java.lang.reflect.Array.getLength(arg) + "]";
        } else {
            return arg.getClass().getSimpleName() + "@" + Integer.toHexString(arg.hashCode());
        }
    }
}

构造函数和静态方法 Hook

// ConstructorAndStaticHooker.java - 构造函数和静态方法 Hook
package com.example.xposed.hook;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import de.robv.android.xposed.XC_MethodHook;
import de.robv.android.xposed.XposedBridge;
import de.robv.android.xposed.XposedHelpers;

public class ConstructorAndStaticHooker {
    
    // Hook 所有构造函数
    public static void hookAllConstructors(String className, ClassLoader classLoader) {
        try {
            Class<?> targetClass = XposedHelpers.findClass(className, classLoader);
            Constructor<?>[] constructors = targetClass.getDeclaredConstructors();
            
            for (Constructor<?> constructor : constructors) {
                XposedBridge.hookMethod(constructor, new XC_MethodHook() {
                    @Override
                    protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                        XposedBridge.log("创建对象: " + className);
                        logConstructorArgs(constructor, param.args);
                    }
                    
                    @Override
                    protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                        XposedBridge.log("对象创建完成: " + className);
                        
                        // 可以在这里修改新创建的对象
                        Object newInstance = param.getResult();
                        if (newInstance != null) {
                            modifyNewInstance(newInstance);
                        }
                    }
                });
            }
        } catch (Throwable t) {
            XposedBridge.log("Hook 构造函数失败: " + t.getMessage());
        }
    }
    
    // Hook 特定参数的构造函数
    public static void hookSpecificConstructor(String className, ClassLoader classLoader, 
                                             Class<?>... parameterTypes) {
        try {
            XposedHelpers.findAndHookConstructor(
                className,
                classLoader,
                parameterTypes,
                new XC_MethodHook() {
                    @Override
                    protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                        XposedBridge.log("Hook 特定构造函数: " + className);
                        
                        // 可以修改构造函数参数
                        modifyConstructorArgs(param);
                    }
                    
                    @Override
                    protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                        // 可以修改新创建的对象属性
                        Object instance = param.getResult();
                        initializeCustomFields(instance);
                    }
                }
            );
        } catch (Throwable t) {
            XposedBridge.log("Hook 特定构造函数失败: " + t.getMessage());
        }
    }
    
    // Hook 所有静态方法
    public static void hookAllStaticMethods(String className, ClassLoader classLoader) {
        try {
            Class<?> targetClass = XposedHelpers.findClass(className, classLoader);
            Method[] methods = targetClass.getDeclaredMethods();
            
            for (Method method : methods) {
                if (Modifier.isStatic(method.getModifiers())) {
                    XposedBridge.hookMethod(method, new XC_MethodHook() {
                        @Override
                        protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                            XposedBridge.log("调用静态方法: " + method.getName());
                        }
                        
                        @Override
                        protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                            // 可以修改静态方法的返回值
                            modifyStaticMethodResult(method, param);
                        }
                    });
                }
            }
        } catch (Throwable t) {
            XposedBridge.log("Hook 静态方法失败: " + t.getMessage());
        }
    }
    
    // 记录构造函数参数
    private static void logConstructorArgs(Constructor<?> constructor, Object[] args) {
        StringBuilder sb = new StringBuilder();
        sb.append("构造函数参数: ");
        
        Class<?>[] paramTypes = constructor.getParameterTypes();
        for (int i = 0; i < paramTypes.length; i++) {
            if (i > 0) sb.append(", ");
            sb.append(paramTypes[i].getSimpleName()).append("=");
            sb.append(args[i] != null ? args[i].toString() : "null");
        }
        
        XposedBridge.log(sb.toString());
    }
    
    // 修改构造函数参数
    private static void modifyConstructorArgs(XC_MethodHook.MethodHookParam param) {
        // 示例：将字符串参数转换为大写
        for (int i = 0; i < param.args.length; i++) {
            if (param.args[i] instanceof String) {
                param.args[i] = ((String) param.args[i]).toUpperCase();
            }
        }
    }
    
    // 修改新创建的对象
    private static void modifyNewInstance(Object instance) {
        try {
            // 示例：设置一个标记字段
            XposedHelpers.setAdditionalInstanceField(instance, "xposed_modified", true);
        } catch (Throwable t) {
            XposedBridge.log("修改新实例失败: " + t.getMessage());
        }
    }
    
    // 初始化自定义字段
    private static void initializeCustomFields(Object instance) {
        try {
            // 添加自定义字段
            XposedHelpers.setAdditionalInstanceField(instance, "creation_time", System.currentTimeMillis());
            XposedHelpers.setAdditionalInstanceField(instance, "xposed_version", XposedBridge.getXposedVersion());
        } catch (Throwable t) {
            XposedBridge.log("初始化自定义字段失败: " + t.getMessage());
        }
    }
    
    // 修改静态方法返回值
    private static void modifyStaticMethodResult(Method method, XC_MethodHook.MethodHookParam param) {
        // 示例：对于返回布尔值的方法，可以强制返回 true
        if (method.getReturnType() == boolean.class || method.getReturnType() == Boolean.class) {
            if (method.getName().contains("check") || method.getName().contains("verify")) {
                param.setResult(true);
                XposedBridge.log("强制 " + method.getName() + " 返回 true");
            }
        }
    }
}

字段访问和修改

// FieldAccessHooker.java - 字段访问 Hook
package com.example.xposed.hook;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;

import de.robv.android.xposed.XC_MethodHook;
import de.robv.android.xposed.XposedBridge;
import de.robv.android.xposed.XposedHelpers;

public class FieldAccessHooker {
    
    // Hook 字段的 getter 和 setter 方法
    public static void hookFieldAccess(String className, ClassLoader classLoader, String fieldName) {
        try {
            Class<?> targetClass = XposedHelpers.findClass(className, classLoader);
            Field field = targetClass.getDeclaredField(fieldName);
            
            // Hook getter 方法
            String getterName = "get" + capitalize(fieldName);
            try {
                XposedHelpers.findAndHookMethod(
                    targetClass,
                    getterName,
                    new XC_MethodHook() {
                        @Override
                        protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                            Object value = param.getResult();
                            XposedBridge.log("读取字段 " + fieldName + ": " + value);
                            
                            // 可以修改返回值
                            if (shouldModifyFieldValue(fieldName, value)) {
                                param.setResult(getModifiedFieldValue(fieldName, value));
                            }
                        }
                    }
                );
            } catch (Throwable t) {
                XposedBridge.log("未找到 getter 方法: " + getterName);
            }
            
            // Hook setter 方法
            String setterName = "set" + capitalize(fieldName);
            try {
                XposedHelpers.findAndHookMethod(
                    targetClass,
                    setterName,
                    field.getType(),
                    new XC_MethodHook() {
                        @Override
                        protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                            Object newValue = param.args[0];
                            XposedBridge.log("设置字段 " + fieldName + ": " + newValue);
                            
                            // 可以修改设置的值
                            if (shouldInterceptFieldSet(fieldName, newValue)) {
                                param.args[0] = getInterceptedFieldValue(fieldName, newValue);
                            }
                        }
                    }
                );
            } catch (Throwable t) {
                XposedBridge.log("未找到 setter 方法: " + setterName);
            }
            
        } catch (Throwable t) {
            XposedBridge.log("Hook 字段访问失败: " + t.getMessage());
        }
    }
    
    // 直接 Hook 字段访问（通过反射）
    public static void hookDirectFieldAccess(String className, ClassLoader classLoader) {
        try {
            Class<?> targetClass = XposedHelpers.findClass(className, classLoader);
            
            // Hook 所有字段的直接访问
            Field[] fields = targetClass.getDeclaredFields();
            for (Field field : fields) {
                if (!Modifier.isStatic(field.getModifiers())) {
                    hookFieldDirectly(field);
                }
            }
        } catch (Throwable t) {
            XposedBridge.log("Hook 直接字段访问失败: " + t.getMessage());
        }
    }
    
    // 监控字段变化
    public static void monitorFieldChanges(Object instance, String fieldName) {
        try {
            // 获取原始值
            Object originalValue = XposedHelpers.getObjectField(instance, fieldName);
            
            // 创建监控器
            FieldChangeMonitor monitor = new FieldChangeMonitor(instance, fieldName, originalValue);
            
            // 定期检查字段变化
            new Thread(monitor).start();
            
        } catch (Throwable t) {
            XposedBridge.log("监控字段变化失败: " + t.getMessage());
        }
    }
    
    // 字段变化监控器
    private static class FieldChangeMonitor implements Runnable {
        private Object instance;
        private String fieldName;
        private Object lastValue;
        private boolean running = true;
        
        public FieldChangeMonitor(Object instance, String fieldName, Object initialValue) {
            this.instance = instance;
            this.fieldName = fieldName;
            this.lastValue = initialValue;
        }
        
        @Override
        public void run() {
            while (running) {
                try {
                    Object currentValue = XposedHelpers.getObjectField(instance, fieldName);
                    
                    if (!objectEquals(lastValue, currentValue)) {
                        XposedBridge.log(String.format(
                            "字段变化检测: %s 从 %s 变为 %s",
                            fieldName, lastValue, currentValue
                        ));
                        lastValue = currentValue;
                    }
                    
                    Thread.sleep(100); // 100ms 检查间隔
                } catch (Throwable t) {
                    XposedBridge.log("字段监控异常: " + t.getMessage());
                    break;
                }
            }
        }
        
        public void stop() {
            running = false;
        }
        
        private boolean objectEquals(Object a, Object b) {
            if (a == null && b == null) return true;
            if (a == null || b == null) return false;
            return a.equals(b);
        }
    }
    
    // 直接 Hook 字段
    private static void hookFieldDirectly(Field field) {
        // 注意：直接 Hook 字段访问在某些情况下可能不稳定
        // 这里提供一个概念性的实现
        
        String fieldName = field.getName();
        Class<?> fieldType = field.getType();
        
        XposedBridge.log("准备 Hook 字段: " + fieldName + " (类型: " + fieldType.getSimpleName() + ")");
        
        // 实际的字段 Hook 需要更底层的实现
        // 这里只是记录字段信息
    }
    
    // 工具方法
    private static String capitalize(String str) {
        if (str == null || str.length() == 0) {
            return str;
        }
        return str.substring(0, 1).toUpperCase() + str.substring(1);
    }
    
    private static boolean shouldModifyFieldValue(String fieldName, Object value) {
        // 根据字段名和值决定是否修改
        return fieldName.contains("license") || fieldName.contains("premium");
    }
    
    private static Object getModifiedFieldValue(String fieldName, Object originalValue) {
        // 返回修改后的值
        if (originalValue instanceof Boolean) {
            return true; // 强制返回 true
        }
        return originalValue;
    }
    
    private static boolean shouldInterceptFieldSet(String fieldName, Object newValue) {
        // 决定是否拦截字段设置
        return fieldName.contains("debug") && Boolean.FALSE.equals(newValue);
    }
    
    private static Object getInterceptedFieldValue(String fieldName, Object originalValue) {
        // 返回拦截后的值
        if (fieldName.contains("debug")) {
            return true; // 强制启用调试
        }
        return originalValue;
    }
}

实际应用案例

应用破解和功能解锁

// AppCrackingHooks.java - 应用破解示例
package com.example.xposed.crack;

import de.robv.android.xposed.IXposedHookLoadPackage;
import de.robv.android.xposed.XC_MethodHook;
import de.robv.android.xposed.XC_MethodReplacement;
import de.robv.android.xposed.XposedBridge;
import de.robv.android.xposed.XposedHelpers;
import de.robv.android.xposed.callbacks.XC_LoadPackage.LoadPackageParam;

public class AppCrackingHooks implements IXposedHookLoadPackage {
    
    private static final String TARGET_PACKAGE = "com.example.paidapp";
    
    @Override
    public void handleLoadPackage(LoadPackageParam lpparam) throws Throwable {
        if (!TARGET_PACKAGE.equals(lpparam.packageName)) {
            return;
        }
        
        XposedBridge.log("开始 Hook 付费应用: " + lpparam.packageName);
        
        // 1. 绕过许可证检查
        bypassLicenseCheck(lpparam);
        
        // 2. 解锁高级功能
        unlockPremiumFeatures(lpparam);
        
        // 3. 移除广告
        removeAds(lpparam);
        
        // 4. 绕过试用期限制
        bypassTrialLimitation(lpparam);
    }
    
    // 绕过许可证检查
    private void bypassLicenseCheck(LoadPackageParam lpparam) {
        try {
            // Hook 许可证验证方法
            XposedHelpers.findAndHookMethod(
                "com.example.paidapp.LicenseChecker",
                lpparam.classLoader,
                "checkLicense",
                new XC_MethodReplacement() {
                    @Override
                    protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
                        XposedBridge.log("绕过许可证检查");
                        return true; // 始终返回已授权
                    }
                }
            );
            
            // Hook 在线验证
            XposedHelpers.findAndHookMethod(
                "com.example.paidapp.OnlineValidator",
                lpparam.classLoader,
                "validateOnline",
                String.class,
                new XC_MethodHook() {
                    @Override
                    protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                        // 强制设置为验证成功
                        param.setResult(true);
                        XposedBridge.log("在线验证被绕过");
                    }
                }
            );
            
        } catch (Throwable t) {
            XposedBridge.log("绕过许可证检查失败: " + t.getMessage());
        }
    }
    
    // 解锁高级功能
    private void unlockPremiumFeatures(LoadPackageParam lpparam) {
        try {
            // Hook 高级功能检查
            XposedHelpers.findAndHookMethod(
                "com.example.paidapp.FeatureManager",
                lpparam.classLoader,
                "isPremiumUser",
                new XC_MethodReplacement() {
                    @Override
                    protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
                        XposedBridge.log("解锁高级用户功能");
                        return true;
                    }
                }
            );
            
            // Hook 功能限制检查
            XposedHelpers.findAndHookMethod(
                "com.example.paidapp.FeatureManager",
                lpparam.classLoader,
                "isFeatureEnabled",
                String.class,
                new XC_MethodHook() {
                    @Override
                    protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                        String featureName = (String) param.args[0];
                        
                        // 解锁特定功能
                        if (featureName.contains("premium") || 
                            featureName.contains("pro") || 
                            featureName.contains("advanced")) {
                            param.setResult(true);
                            XposedBridge.log("解锁功能: " + featureName);
                        }
                    }
                }
            );
            
        } catch (Throwable t) {
            XposedBridge.log("解锁高级功能失败: " + t.getMessage());
        }
    }
    
    // 移除广告
    private void removeAds(LoadPackageParam lpparam) {
        try {
            // Hook 广告显示方法
            XposedHelpers.findAndHookMethod(
                "com.example.paidapp.AdManager",
                lpparam.classLoader,
                "showAd",
                new XC_MethodReplacement() {
                    @Override
                    protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
                        XposedBridge.log("阻止广告显示");
                        return null; // 不显示广告
                    }
                }
            );
            
            // Hook 广告加载
            XposedHelpers.findAndHookMethod(
                "com.example.paidapp.AdManager",
                lpparam.classLoader,
                "loadAd",
                new XC_MethodReplacement() {
                    @Override
                    protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
                        XposedBridge.log("阻止广告加载");
                        return null;
                    }
                }
            );
            
            // Hook 广告状态检查
            XposedHelpers.findAndHookMethod(
                "com.example.paidapp.AdManager",
                lpparam.classLoader,
                "isAdFree",
                new XC_MethodReplacement() {
                    @Override
                    protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
                        return true; // 始终返回无广告状态
                    }
                }
            );
            
        } catch (Throwable t) {
            XposedBridge.log("移除广告失败: " + t.getMessage());
        }
    }
    
    // 绕过试用期限制
    private void bypassTrialLimitation(LoadPackageParam lpparam) {
        try {
            // Hook 试用期检查
            XposedHelpers.findAndHookMethod(
                "com.example.paidapp.TrialManager",
                lpparam.classLoader,
                "isTrialExpired",
                new XC_MethodReplacement() {
                    @Override
                    protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
                        XposedBridge.log("绕过试用期检查");
                        return false; // 试用期永不过期
                    }
                }
            );
            
            // Hook 剩余天数计算
            XposedHelpers.findAndHookMethod(
                "com.example.paidapp.TrialManager",
                lpparam.classLoader,
                "getRemainingDays",
                new XC_MethodReplacement() {
                    @Override
                    protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
                        return 999; // 返回大量剩余天数
                    }
                }
            );
            
            // Hook 首次安装时间
            XposedHelpers.findAndHookMethod(
                "com.example.paidapp.TrialManager",
                lpparam.classLoader,
                "getInstallTime",
                new XC_MethodReplacement() {
                    @Override
                    protected Object replaceHookedMethod(MethodHookParam param) throws Throwable {
                        // 返回当前时间，使试用期重新开始
                        return System.currentTimeMillis();
                    }
                }
            );
            
        } catch (Throwable t) {
            XposedBridge.log("绕过试用期限制失败: " + t.getMessage());
        }
    }
}

总结

Xposed Hook 技术的核心要点：

🎯 技术原理

方法拦截：在运行时拦截方法调用
参数修改：动态修改方法参数和返回值
行为改变：不修改源码改变应用行为
运行时注入：在应用加载时注入 Hook 代码

✅ 高级技巧

动态方法查找和批量 Hook
构造函数和静态方法处理
字段访问监控和修改
复杂参数类型的处理

🚀 实际应用

应用功能解锁和破解
系统行为定制和优化
安全研究和漏洞分析
应用调试和逆向工程

⚠️ 注意事项

遵守法律法规和道德规范
注意应用稳定性和兼容性
处理好异常和错误情况
考虑性能影响和资源消耗

掌握 Xposed Hook 技术，深入理解 Android 运行时机制！

Hook 技术是双刃剑，应当在合法合规的前提下使用，用于学习研究和正当目的。