Android:根据上下文Context获取Activity

根据Context获取Activity：

Java中的写法.

    private Activity getActivity() {
        Context context = getContext();
        while (!(context instanceof Activity) && context instanceof ContextWrapper) {
            context = ((ContextWrapper) context).getBaseContext();
        }

        if (context instanceof Activity) {
            return (Activity) context;
        }
        throw new FacebookException("Unable to get Activity.");
    }
    

Kotlin中的写法

    private fun getActivity(): Activity? {
        var context = context
        while (context !is Activity && context is ContextWrapper) {
            context = context.baseContext
        }
        if (context is Activity) {
            return context
        }
        return null
    }