想嘗試一種新的熱修復(fù)方式，替換應(yīng)用的ClassLoader，在loadclass中如果碰到修復(fù)類存在，則替換掉原來的類，但是失敗了，記錄下歷程：
首先自定義一個(gè)ClassLoader

public class MyPathClassLoader extends BaseDexClassLoader {
    private static final String TAG = "MyPathClassLoader";
    public MyPathClassLoader(String dexPath, ClassLoader parent) {
        super(dexPath, null, null, parent);
        Log.d(TAG, "dexpath1: "+dexPath);
    }

    public MyPathClassLoader(String dexPath, String librarySearchPath, ClassLoader parent) {
        super(dexPath, null, librarySearchPath, parent);
        Log.d(TAG, "dexpath2: "+dexPath + " librarySearchPath:"+ librarySearchPath);
    }

    @Override
    public Class<?> loadClass(String name) throws ClassNotFoundException {
        Log.d(TAG, "loadClass: "+name);
        return super.loadClass(name);
    }


    @Override
    protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
        Log.d(TAG, "loadClass : "+name +" resolve:"+resolve);
        return super.loadClass(name, resolve);
    }

    @Override
    protected Class<?> findClass(String name) throws ClassNotFoundException {
        Log.d(TAG, "findClass: "+name);
        return super.findClass(name);
    }

    @Override
    public String findLibrary(String name) {
        Log.d(TAG, "findLibrary: "+name);
        return super.findLibrary(name);
    }
}

在application的attachBaseContext方法中替換classloader，替換除了application之外的所有類的classloader，

override fun attachBaseContext(base: Context) {
        super.attachBaseContext(base)

        val appInfo: ApplicationInfo = applicationInfo
        val apkPath = appInfo.sourceDir
     val classLoader =
            MyPathClassLoader(apkPath, classLoader)
        hookPackageClassLoader(base, classLoader)
}

 private fun hookPackageClassLoader(context: Context, appClassLoaderNew: ClassLoader): Boolean {
        try {
            val packageInfoField: Field =
                Class.forName("android.app.ContextImpl").getDeclaredField("mPackageInfo")
            packageInfoField.isAccessible = true
            val loadedApkObject: Any = packageInfoField.get(baseContext)
            var LoadedApkClass = Class.forName("android.app.LoadedApk")
//            val getClassLoaderMethod: Method = LoadedApkClass.getDeclaredMethod("getClassLoader")
//            val appClassLoaderOld = getClassLoaderMethod.invoke(loadedApkObject) as ClassLoader
            val appClassLoaderField: Field = LoadedApkClass.getDeclaredField("mClassLoader")
            appClassLoaderField.isAccessible = true
            appClassLoaderField.set(loadedApkObject, appClassLoaderNew)
            return true
        } catch (ignored: Throwable) {
            Log.d("MyPathClassLoader", "error:"+ignored.message)
        }
        return false
    }

但是在MainActivity測試效果時(shí)發(fā)現(xiàn)TestA類，并沒有由自定義的類加載器加載，而是PathClassLoader加載的，應(yīng)該是由于android N混合編譯，安裝過程中提前加載了部分熱點(diǎn)類導(dǎo)致的，實(shí)驗(yàn)失敗。。

  override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        Log.d("MyPathClassLoader", "testa classloader:"+TestA().javaClass.classLoader.toString())

        TestA().doSomething()
        Log.d("MyPathClassLoader", "classcloader:"+MainActivity.javaClass.classLoader.toString())

如果繼續(xù)下去，應(yīng)該跟tinker一樣了，所以沒有繼續(xù)。如果想嘗試asm直接更新編譯后的class，應(yīng)該會導(dǎo)致應(yīng)用校驗(yàn)問題，其他的java后端的hotreload方法，由于android使用的不是jvm虛擬機(jī)也無法使用，比如JRebel和HotSwap，大家還有啥好的想法嗎
refer：https://cloud.tencent.com/developer/article/1012644
https://mp.weixin.qq.com/s?__biz=MzAwNDY1ODY2OQ==&mid=2649286341&idx=1&sn=054d595af6e824cbe4edd79427fc2706&scene=0#wechat_redirect