刚切换就让PullToRefreshListView呈现下拉状态刷新

if (HttpTool.isNetworkConnected(this)) {
            // 开始就呈现下拉状态
            new Handler().postDelayed(new Runnable() {

                @Override
                public void run() {
                    pullToRefreshListView.setRefreshing(true);
                }
            }, 500);
            //getVideoUrls();
        } else {
            Toast.makeText(this, "请检查网络", Toast.LENGTH_SHORT).show();
        }