public async Task UpdatePostsAsync()
{
try
{
//Update from backend if possible and update database
var newPosts = await JsonPlaceholderHelper.GetPostsAsync();
await App.Locator.PostDatabaseHelper.AddOrUpdatePostsAsync(newPosts);
}
catch (HttpRequestException e)
{
System.Diagnostics.Debug.WriteLine($"HTTP request exception {e.Message}");
}
//Always dispay what's in the database
var databasePosts = await App.Locator.PostDatabaseHelper.getPostsAsync();
//The following algorithm allows to replace only the items that changed in the observable collection
for (int i = 0; i < databasePosts.Count; i += 1)
{
if (Posts.Count <= i)
{
Posts.Add(databasePosts[i]);
}
else if (databasePosts[i].Id != Posts[i].Id)
{
Posts[i] = databasePosts[i];
}
}
//delete remaining items in the Posts collection
for (int i = databasePosts.Count; i < Posts.Count; i += 1)
{
Posts.RemoveAt(i);
}
}
public async Task UpdatePostsAsync()
{
var newPosts = await JsonPlaceholderHelper.GetPostsAsync();
this.Posts.Clear();
newPosts.ForEach((post) =>
{
this.Posts.Add(post);
});
}
public async Task UpdatePostsAsync()
{
var newPosts = await JsonPlaceholderHelper.GetPostsAsync();
this.Posts.Clear();
newPosts.ForEach((post) =>
{
post.ImageUrl = "https://picsum.photos/70/?image=" + newPosts.IndexOf(post);
this.Posts.Add(post);
});
}
