protected async Task LoadAnswer(int questionId)
{
AnswerInfo currentAnswer = null;
// 1. Load from the database
currentAnswer = await App.StackDataManager.Database.GetAnswerForQuestion(questionId);
if (currentAnswer != null)
{
_theAnswer.AnswerID = currentAnswer.AnswerID;
_theAnswer.QuestionID = currentAnswer.QuestionID;
_theAnswer.AnswerBody = currentAnswer.AnswerBody;
}
else
{
// 2. No database record... Load answer from the web
var answerAPI = new StackOverflowService();
var downloadedAnswer = await answerAPI.GetAnswerForQuestion(questionId);
if (downloadedAnswer != null)
{
_theAnswer.AnswerID = downloadedAnswer.AnswerID;
_theAnswer.QuestionID = downloadedAnswer.QuestionID;
_theAnswer.AnswerBody = downloadedAnswer.AnswerBody;
// 3. Save the answer for next time
await App.StackDataManager.Database.SaveAnswer(_theAnswer);
}
else
{
_theAnswer.AnswerBody = "No answer found";
}
}
}
public async Task <AnswerInfo> GetAnswerForQuestion(int questionId)
{
if (!CrossConnectivity.Current.IsConnected)
{
throw new NoInternetException();
}
var decompressedContent = await this.CallAndDecompress(string.Format(ANSWER_URL, questionId));
var deserializedContent = JsonConvert.DeserializeObject <AnswerResponse> (decompressedContent);
AnswerInfo theAnswer = null;
if (deserializedContent != null && deserializedContent.items != null && deserializedContent.items.Count > 0)
{
var currAnswer = deserializedContent.items [0];
theAnswer = new AnswerInfo {
AnswerID = currAnswer.answer_id,
QuestionID = currAnswer.question_id,
AnswerBody = currAnswer.body,
LoadedFromWeb = true
};
}
return(theAnswer);
}
public QuestionDetailPage(int questionId)
{
_theAnswer = new AnswerInfo();
Title = "Possible Answer";
Label loadedFromLabel = new Label {
MinimumHeightRequest = 50,
XAlign = TextAlignment.Center
};
HtmlWebViewSource webSource = new HtmlWebViewSource();
webSource.BindingContext = _theAnswer;
webSource.SetBinding(HtmlWebViewSource.HtmlProperty, new Binding("AnswerBody"));
_theFullAnswer = new WebView {
Source = webSource,
VerticalOptions = LayoutOptions.FillAndExpand
};
Content = new StackLayout {
VerticalOptions = LayoutOptions.FillAndExpand,
Children =
{
_theFullAnswer
}
};
Task.Run(async() => {
await LoadAnswer(questionId);
});
}
public async Task SaveAnswer(AnswerInfo answer)
{
int answerId = answer.AnswerID;
var dbRecord = await Table <AnswerInfo> ()
.Where(ai => ai.AnswerID == answerId)
.FirstOrDefaultAsync().ConfigureAwait(false);
if (dbRecord == null)
{
await InsertAsync(answer).ConfigureAwait(false);
}
else
{
await UpdateAsync(answer).ConfigureAwait(false);
}
}