[Android]朝花夕拾之使用DexClassLoader动态加载广点通jar包

cl.loadClass(“com.qq.e.ads.LandscapeADActivity”);

Log.d(“zyl”, “init success”);
return true;
} catch (IllegalArgumentException e) {
Log.d(“zyl”, "IllegalArgumentException = " + e.getMessage());
} catch (IllegalAccessException e) {
Log.d(“zyl”, "IllegalArgumentException = " + e.getMessage());
} catch (InvocationTargetException e) {
Log.d(“zyl”, "IllegalArgumentException = " + e.getMessage());
} catch (Exception e) {
Log.d(“zyl”, "GdtException = " + e.getMessage());
}

GdtInvokeHandler的实现：

private AdCallBack mAdCallback;

public GdtInvokeHandler(AdCallBack adCallBack) {
mAdCallback = adCallBack;
}

@Override
public Object invoke(Object proxy, Method method, Object[] args) {
Log.d(“zyl”, "InvokeHandler = " + method.getName());
if (“onADLoaded”.equals(method.getName())) {
if (args != null && args.length > 0) {
List list = (List) args[0];
if (list != null && list.size() > 0) {
List tempList = new ArrayList<>();
for (int i = 0; i < list.size(); i++) {
Object object = list.get(i);
GdtModelView view = new GdtModelView(object);
view.render();
tempList.add(view);
}
mAdCallback.onAdLoaded(tempList);
}
}
} else if (“onRenderFail”.equals(method.getName())) {

} else if (“onRenderSuccess”.equals(method.getName()
)) {

} else if (“onADExposure”.equals(method.getName())) {

} else if (“onADClicked”.equals(method.getName())) {

} else if (“onADClosed”.equals(method.getName())) {

} else if (“onADLeftApplication”.equals(method.getName())) {

} else if (“onADOpenOverlay”.equals(method.getName())) {

} else if (“onADCloseOverlay”.equals(method.getName())) {

} else if (“onNoAD”.equals(method.getName())) {
Object object = args[0];

Class clazz = object.getClass();
try {
Method errorMethod = clazz.getDeclaredMethod(“getErrorMsg”);
errorMethod.setAccessible(true);
String errorMessage = (String)errorMethod.invoke(object);
Log.d(“zyl”, "errorMessage = " + errorMessage);
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}

}
return null;
}

主要是讲广告回调的监听全都转到InvokeHandler中并在此处理相关逻辑

广点通广告需要打开SDK中定义的Activity和Service，如果用自定义的类加载器去加载，它只是加载了Activity和Service相关类，没有经过AMS的处理，是不可能有生命周期方法、window、view等的创建的，怎么办呢，我们需要让系统的类加载器可以加载jar包所在路径的类，这样在启动Activity时，它会有相关处理，变成一个正常的Actiivity/Service。这个逻辑的处理在loadApkClassLoader方法：

private static void loadApkClassLoader(Context context, DexClassLoader dLoader){
try{
Object currentActivityThread = RefInvoke.invokeStaticMethod(
“android.app.ActivityThread”, “currentActivityThread”,
new Class[] {}, new Object[] {});//获取主线程对象
String packageName = context.getPackageName();//当前apk的包名
ArrayMap mPackages = (ArrayMap) RefInvoke.getFieldOjbect(
“android.app.ActivityThread”, currentActivityThread,
“mPackages”);
WeakReference wr = (WeakReference) mPackages.get(packageName);
RefInvoke.setFieldOjbect(“android.app.LoadedApk”, “mClassLoader”,
wr.get(), dLoader);
Log.i(“zyl”, “classloader:”+dLoader);
}catch(Exception e){
Log.i(“zyl”, “load apk classloader error:”+Log.getStackTraceString(e));
}
}

这时候就有同学问了，你把这个类加载器替换了，那么它不就只能加载jar包路径下的类了么，那我App中的类岂不是加载不了了？放心，不会有这个问题，看下类加载器的创建：

DexClassLoader cl = new DexClassLoader(jarPath, tmpPath
, tmpPath, context.getClassLoader());

最后一个参数parent，它所传的实参context.getClassLoader()，和LoadedApk中的是同一个，也就是说，我们定义了一个加强版类加载器，它既可以加载主APK所在路径的类，也可以加载jar包所在路径的类

public void loadGdtAd() {
if (!inited) {
inited = init(mContext, mAdCallBack);
if (!inited) {
return;
}
}
try {
loadAdMethod.invoke(gdtObject, new Object[] {10});
} catch (IllegalAccessException e) {
Log.d(“zyl”, "loadGdtAd IllegalAccessException = " + e.getMessage());
e.printStackTrace();
} catch (InvocationTargetException e) {
Log.d(“zyl”, "loadGdtAd InvocationTargetException = " + e.getMessage());
} catch (Exception e) {
Log.d(“zyl”, "loadGdtAd Exception = " + e.getMessage());
}
ocationTargetException = " + e.getMessage());
} catch (Exception e) {
Log.d(“zyl”, "loadGdtAd Exception = " + e.getMessage());
}