async void GetTweets()
{
tweets = await DataService.GetTweetList();
listView1.Adapter = new Droid.Adapters.TweetAdapter(this, tweets);
}
async void btnTweet_ClickAsync(object sender, System.EventArgs e)
{
tweets = await DataService.GetTweetList();
listView1.Adapter = new TweetAdapter(this, tweets);
}