activity.runOnUiThread（）内的run（）方法没有被执行

activity.runOnUiThread(new Runnable() {
                public void run()
                {
                    Toast.makeText(context, toast, Toast.LENGTH_SHORT).show();
                }
            });

run（）方法没有执行，查找缘由，在原来，掉用runOnUiThread的activity，必定得是Activity对象，so，在使用以前，须要增长判读：

if（activity instanceOf Activity）{

}

参考连接 

原文：

It doesn't always work, you have to be sure that what you are casting is
 effectively an Activity or you'll have a ClassCastException. To do that you can do "if(context instanceOf Activity){ // proceed to cast }"