Xposed学习三：

在上一篇我们留下问题：handleLoadPackage如何生效即在何时被执行。本篇我们会对Xposed学习一中的操作步骤剖析背后原理。

　先看XposedBridge.class的main：

 1 private static void main(String[] args) {
 2         String startClassName = getStartClassName();
 3             ......
 4             if(initNative()) {
 5                 if(startClassName == null) {
 6                     initXbridgeZygote();
 7                 }
 8                 // 读取/data/data/de.robv.android.xposed.installer/conf/modules.list内容,存储着模块apk的地址，
 9                 // 内容：/data/app/com.jason.learnxposed-2.apk
10                 // 加载模块loadModule(APK,startClassName)
11                 loadModules(startClassName);
12             }
13             ......
14         if(startClassName == null) {
15             ZygoteInit.main(args);
16         } else {
17             RuntimeInit.main(args);
18         }
20     }

main中分两步：loadModules；2 init。loadModules简单先分析这个

 private static void loadModule(String apk, String startClassName) {
      ......
            PathClassLoader mcl = new PathClassLoader(apk, BOOTCLASSLOADER);
            InputStream is = mcl.getResourceAsStream("assets/xposed_init");
            // 读取apk的assets/xposed_init内容，Xposed学习一中的第五步
            if(is == null) {
                log("assets/xposed_init not found in the APK");
            } else {
                BufferedReader moduleClassesReader = new BufferedReader(new InputStreamReader(is));
                    ......
                    if(startClassName == null) {
                        if(moduleInstance instanceof IXposedHookZygoteInit) {
                            StartupParam param = new StartupParam();
                            param.modulePath = apk;
                            ((IXposedHookZygoteInit)moduleInstance).initZygote(param);
                        }

                        if(moduleInstance instanceof IXposedHookLoadPackage) {
                            hookLoadPackage(new Wrapper((IXposedHookLoadPackage)moduleInstance));
                        }

                        if(moduleInstance instanceof IXposedHookInitPackageResources) {
                       hookInitPackageResources(new de.robv.android.xposed.IXposedHookInitPackageResources.Wrapper((IXposedHookInitPackageResources)moduleInstance));
                        }
                    } else if(moduleInstance instanceof IXposedHookCmdInit) {
                        de.robv.android.xposed.IXposedHookCmdInit.StartupParam param1 = new de.robv.android.xposed.IXposedHookCmdInit.StartupParam();
                        param1.modulePath = apk;
                        param1.startClassName = startClassName;
                        ((IXposedHookCmdInit)moduleInstance).initCmdApp(param1);
                    }
                     ......
            }
        }
    }

　　简单说下loadModule中步骤，1.读取Xposed_init文本里的内容，里面是我们的类名。我们可以在一个模块中写好几个功能的类，但请注意一定要将类全名字符串写到Xposed_init里且每个类字符串为一行。