lsposed开发hook找不到类

app加壳找不到类时使用

package com.example.demoapp;

import android.app.Application;
import android.content.Context;
import android.util.Log;

import java.util.Arrays;

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


public class HookDemo implements IXposedHookLoadPackage {
    private static final String TARGET_PACKAGE = "com.dachuan.news";
    private static final String TARGET_CLASS = "cn.thecover.lib.common.manager.SignManager";
    private static final String TARGET_METHOD = "getSign";
    private static final String TAG = "HookDemo";

    public void handleLoadPackage(XC_LoadPackage.LoadPackageParam lpparam) throws Throwable {
        if (!TARGET_PACKAGE.equals(lpparam.packageName) || !lpparam.processName.equals(lpparam.packageName)) {
            return;
        }
        XposedHelpers.findAndHookMethod(Application.class, "attach", Context.class, new XC_MethodHook() {
            @Override
            protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                ClassLoader classLoader = ((Context) param.args[0]).getClassLoader();
                Class<?> targetClass = XposedHelpers.findClassIfExists(TARGET_CLASS, classLoader);
                if (targetClass != null) {
                    XposedHelpers.findAndHookMethod(targetClass, TARGET_METHOD, String.class, String.class, String.class, new XC_MethodHook() {
                        @Override
                        protected void beforeHookedMethod(MethodHookParam param) {
                            Log.i(TAG, String.format("%s参数: %s", TARGET_METHOD, Arrays.toString(param.args)));
                        }
                        @Override
                        protected void afterHookedMethod(MethodHookParam param) {
                            Log.i(TAG, String.format("%s返回值: %s", TARGET_METHOD, param.getResult()));

                        }
                    });
                }

            }
        });
    }
}