android获取当前打开的栈顶的Activity包名类名

ActivityManager manager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
RunningTaskInfo info = manager.getRunningTasks(1).get(0);
String shortClassName = info.topActivity.getShortClassName(); //类名
String className = info.topActivity.getClassName(); //完整类名
String packageName = info.topActivity.getPackageName(); //包名

最后不要忘记在AndroidManifest.xml中增加权限：

<uses-permission android:name = "android.permission.GET_TASKS"/>