I navigate between pages with Navigation Helper class which VS 2013 added when solution created, But scroll state most of controls (Like Pivot, Hub) does not saved like in Windows Phone 8.x Silverlight.
What should I do for implement this behaviour? Should I handle scrolling state by myself and restore scroll when i go back in visited page?
Thanks.
UPDATE1:
I need save selected pivot/hub item etc, when i go back to page.
UPDATE2:
void navigationHelper_SaveState(obj sender,SaveStateEventArgs e)
{
e.PageState["SelectedSection"] = MainHub.SectionsInView;
}
void navigationHelper_LoadState(obj sender,LoadStateEventArgs e)
{
if (e.PageState != null)
{
var sections = e.PageState["SelectedSection"] as IList<HubSection>;
if (sections != null && sections.Any())
MainHub.ScrollToSection(sections[0]);
}
}
On the page where you use the hub, set the navigation cache mode in constructor:
this.NavigationCacheMode = NavigationCacheMode.Enabled;
or in XAML:
<Page
x:Class="App.HubPage"
....
xmlns:data="using:App.Data"
NavigationCacheMode="Enabled"
....
Better use:
this.NavigationCacheMode = NavigationCacheMode.Required;
before:
this.InitializeComponent();
And add:
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
if (e.NavigationMode == NavigationMode.Back)
this.NavigationCacheMode = NavigationCacheMode.Disabled;
}
to remove cache on back navigation from page.
Related
I have a recyclerview set up in xamarin.android as per the code in this link
https://www.appliedcodelog.com/2019/08/reorder-list-items-by-drag-and-drop-in.html
My question is, how can I remember the position of these items when the app is restarted etc. When the user adds items they are inserted at adapter position 0,1,2,3 etc but when they close the app and come back in, it is not always in the same order.
The user can also rearrange by drag and drop so this seems to add even more confusion!
Currently I have the items in the recyclerview being saved by converting the list to Json and loading when the app opens again but as I said, the items aren't always in the same order as before the app was closed.
Can anyone advise the best way to do this? I have tried to add the item name and position number to a list converting to json then trying to insert the item at the saved position index but can't get it to work..
Thanks
Do you want to achieve the result like following GIF?
You can use PreferenceManager to store position of items(Before store data, I will Serialize data) in a recyclerview.
You can override OnPause() method, this method will be executed when application is background or app is killed. So we can store the position and data in this method.Here is code about ReOrderActivity
[Activity(Label = "ReOrderList")]
public class ReOrderActivity : Activity, IOnStartDragListener
{
private ItemTouchHelper _mItemTouchHelper;
public static ObservableCollection<string> ResourceList;
private RecyclerView _resourceReorderRecyclerView;
ReOrderAdapters resourceAdapter;
ISharedPreferences prefs;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
SetContentView(Resource.Layout.ReOrderLayout);
prefs = PreferenceManager.GetDefaultSharedPreferences(this);
GetCollection();
resourceAdapter = new ReOrderAdapters(ResourceList, this);
// Initialize the recycler view.
_resourceReorderRecyclerView = FindViewById<RecyclerView>(Resource.Id.ResourceReorderRecyclerView);
Button mDone = FindViewById<Button>(Resource.Id.mDone);
mDone.Click += MDone_Click;
_resourceReorderRecyclerView.SetLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.Vertical, false));
_resourceReorderRecyclerView.SetAdapter(resourceAdapter);
_resourceReorderRecyclerView.HasFixedSize = true;
ItemTouchHelper.Callback callback = new SimpleItemTouchHelperCallback(resourceAdapter);
_mItemTouchHelper = new ItemTouchHelper(callback);
_mItemTouchHelper.AttachToRecyclerView(_resourceReorderRecyclerView);
}
protected override void OnPause()
{
base.OnPause();
string ConvertData = JsonConvert.SerializeObject(ResourceList);
ISharedPreferencesEditor editor = prefs.Edit();
editor.PutString("ObservableCollection_ConvertData", ConvertData);
// editor.Commit(); // applies changes synchronously on older APIs
editor.Apply(); // applies changes asynchronously on newer APIs
}
private void MDone_Click(object sender, System.EventArgs e)
{
resourceAdapter.AddItem("Add item");
}
public void OnStartDrag(RecyclerView.ViewHolder viewHolder)
{
_mItemTouchHelper.StartDrag(viewHolder);
}
//Added sample data record here
public void GetCollection()
{
//ISharedPreferencesEditor editor = prefs.Edit();
//editor.PutString("ObservableCollection_ConvertData", "");
//editor.Apply();
string ConvertData = prefs.GetString("ObservableCollection_ConvertData","");
if(string.IsNullOrEmpty(ConvertData))
{
ResourceList = new ObservableCollection<string>();
ResourceList.Add("OnPause()");
ResourceList.Add("OnStart()");
ResourceList.Add("OnCreate()");
}
else
{
ResourceList= JsonConvert.DeserializeObject<ObservableCollection<string>>(ConvertData);
}
//var or= ResourceList.ToString();
}
}
}
You can download my demo
https://drive.google.com/file/d/1mQTKf3rlcIVnf2N97amrqtnrSCRk-8ZW/view?usp=sharing
I just want to be able to display a list of contacts (without even communicating to a server) just the way it is displayed on the "Contacts" native app on the phone.
I have like 1500 contacts and when I try to load the recycler view, all items at once, it lags a lot 2 - 3 seconds.
I've achieved loading more items but with a loading bar and thats not what I want.
I've already tried Threads, Executors, postOnUIThread(), handler.post() and even AsyncTask -> Override -> doOnBackground. Nothing works.
private class CustomTask extends AsyncTask<Void, Void, Void> {
int inserted;
#Override
protected Void doInBackground(Void... param) {
//Do some work
try {
lcf.getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
((BaseActivity) lcf.getActivity()).showProgressDialog();
}
});
int currentSize = contactsLoaded.size();
for (inserted = 0; inserted < lcf.getController().getContacts().size() && contactsLoaded.size() < lcf.getController().getContacts().size(); inserted++) {
contactsLoaded.add(lcf.getController().getContacts().get(currentSize + inserted));
notifyItemRangeInserted(contactsLoaded.size() - 1, inserted);
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void param) {
//Print Toast or open dialog
//notifyItemRangeInserted(contactsLoaded.size() - 1, 0);
if(!lcf.getController().isSelectedAffiliated()){
lcf.disclaimerLayout.setVisibility(View.VISIBLE);
}else{
lcf.disclaimerLayout.setVisibility(View.GONE);
}
lcf.isLoading=false;
((BaseActivity) lcf.getActivity()).hideProgressDialog();
}
}
That code lives within my adapter, "lcf" is a reference to the fragment. If I use the already loaded list saved on the controller (that I get from the fragment reference) and then just call notifyDataSetChanged() it LAGS like hell. So with this CustomTask I tried to load every item and notify it one by one to a Background task hoping it would make the items pop up quickly and sequentially without interfereing with the UI thread to not freeze the screen. It doesn't work. I am out of options now. I've tried everything.
I'm working on Eclipse plugin and I add an 16x16 icon to the statusbar by
ToolBarManager manager = new ToolBarManager(SWT.FLAT | SWT.HORIZONTAL);
manager.add(updatingNewsAction);
Where updatingNewsAction is a class that extends org.eclipse.jface.action.Action.
However I've got problem with removing the updatingNewsAction from the toolbar. It's removed, but I can see that only when something updates the statusbar - for example minimazing/maximazing the borderline views. Then after reading some blog post I've wrote:
PlatformUI.getWorkbench().getDisplay().asyncExec(new Runnable() {
#Override
public void run() {
IWorkbench wb = PlatformUI.getWorkbench();
IWorkbenchWindow win = wb.getActiveWorkbenchWindow();
IWorkbenchPage page = win.getActivePage();
IWorkbenchPart part = page.getActivePart();
IWorkbenchPartSite site = part.getSite();
IViewSite vSite = (IViewSite) site;
IActionBars actionBars = vSite.getActionBars();
if (actionBars == null) {
return;
}
IStatusLineManager statusLineManager = actionBars.getStatusLineManager();
if (statusLineManager == null) {
return;
}
statusLineManager.update(true);
}
});
Which is a step forward, because it gets updated when switching focus between views, but still it doesn't happen immediately and without user interactions. How to update the status bar programmatically immediately?
I have a Windows 8 app, and recently I refactored it to use a 'master page'. This means that there is one 'layout' that has a few generic components such as the header and footer. In that layout, I have a Frame. Every time I want to show a different view, I load it in the frame.
This means that my startup screen is no longer of type Frame but of type Layout, which is a LayoutAwarePage. This is how I initialize it in App.xaml.cs OnLaunched:
Layout rootFrame = Window.Current.Content as Layout;
if (rootFrame == null)
{
rootFrame = new Layout();
Here comes the problem: I have a charms flyout that contains a few items like Settings. I made a nice view (Flayouts.xaml) that contains the layout of these flyouts. The code behind for that view looks like this:
public Flyouts()
{
InitializeComponent();
SettingsPane.GetForCurrentView().CommandsRequested += Flyouts_CommandsRequested;
}
void Flyouts_CommandsRequested(SettingsPane sender, SettingsPaneCommandsRequestedEventArgs args)
{
// add some commands
}
And this is how you'd get this to work in your app:
Frame rootFrame = Window.Current.Content as Frame;
if (rootFrame == null)
{
rootFrame = new CharmFlyoutLibrary.CharmFrame { CharmContent = new Flyouts() };
What they're doing here is assigning a Frame to 'rootFrame'. However, since I switched to a master page, I no longer have a Frame but a Layout/LayoutAwarePage type, so I can't assign the CharmFrame to it. How do I overcome this problem?
Anyone?
When navigating inside a frame the page that you navigate to is placed inside the navigate the Content property.
So if you navigate to you Layout first, then the content will be filled with your page and you can navigate to your child page's. I've placed a example below
Frame rootFrame = Window.Current.Content as Frame;
// Do not repeat app initialization when the Window already has content,
// just ensure that the window is active
if (rootFrame == null) {
// Create a Frame to act as the navigation context and navigate to the first page
rootFrame = new Frame();
//Associate the frame with a SuspensionManager key
SuspensionManager.RegisterFrame(rootFrame, "AppFrame");
if (args.PreviousExecutionState == ApplicationExecutionState.Terminated) {
// Restore the saved session state only when appropriate
try {
await SuspensionManager.RestoreAsync();
} catch (SuspensionManagerException) {
//Something went wrong restoring state.
//Assume there is no state and continue
}
}
// Place the frame in the current Window
Window.Current.Content = rootFrame;
}
if (rootFrame.Content == null) {
if (rootFrame.Navigate(typeof(Layout))) {
var secondFrame = rootFrame.Content as Layout;
if (!secondFrame.ContentFrame.Navigate(typeof(YourPage)) {
throw new Exception("Failed to create initial page");
}
}
}
I need to register different share charm listener for every page. I have 2 pages. I added following code in every one:
DataTransferManager.GetForCurrentView().DataRequested += App_DataRequested;
I added it in constructor of one page and in UserControl_Loaded event of another (first page just doesn't have UserControl_Loaded so why I added it directly to constructor). At the moment when second page tryting to load, I got exception:
WinRT information: An event handler has already been registered
Additional information: A method was called at an unexpected time.
Where should I place it and what is "right" time to do this??
Also it looks confusing that we have different DataTransferManager for every view, but only one is active at current time. Ever more, I noticed, if you add only one listener for first page, other pages will share this listener anyway. If I have only one shared listener for all pages, is it correct register it in app.xaml.cs?
The way I resolved this issue was to deregister the event in the onNavigatedfrom event as below:
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
DataTransferManager.GetForCurrentView().DataRequested -= App_DataRequested;
base.OnNavigatedFrom(e);
}
In BasePage.cs in constructor I added
public BasePage()
{
if (!_isListenToDataRequested)
{
_isListenToDataRequested = true;
DataTransferManager manager = DataTransferManager.GetForCurrentView();
manager.DataRequested += AppDataRequested;
}
}
private async void AppDataRequested(DataTransferManager sender, DataRequestedEventArgs args)
{
IShareable shareable = Frame.Content as IShareable;
if (shareable != null)
{
DataRequestDeferral deferral = args.Request.GetDeferral();
await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => shareable.AppDataRequested(sender, args));
deferral.Complete();
}
}
And all my pages look like
public sealed partial class ContentPage : IShareable
{
public void AppDataRequested(DataTransferManager sender, DataRequestedEventArgs args)
{...}
}
Another solution was run this as below
private DataTransferManager dataTransferManager;
Put this in page loaded event
this.Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, new DispatchedHandler(() =>
{
this.dataTransferManager = DataTransferManager.GetForCurrentView();
this.dataTransferManager.DataRequested += new TypedEventHandler<DataTransferManager, DataRequestedEventArgs>(this.OnDataRequested);
}));
And
protected override void OnNavigatedFrom(NavigationEventArgs e)
{
// Unregister the current page as a share source.
this.dataTransferManager.DataRequested -=
new TypedEventHandler<DataTransferManager, DataRequestedEventArgs>
(this.OnDataRequested);
}
I'd suggest doing it in the navigating events, the OnNavigatingFrom event will be triggered before the OnNavigatingTo of the page you're going to so you won't have this problem.
protected override Task OnNavigatingTo(WinRTXamlToolkit.Controls.AlternativeNavigationEventArgs e)
{
DataTransferManager.GetForCurrentView().DataRequested += dataTransfer_DataRequested;
return base.OnNavigatingTo(e);
}
protected override Task OnNavigatingFrom(WinRTXamlToolkit.Controls.AlternativeNavigatingCancelEventArgs e)
{
DataTransferManager.GetForCurrentView().DataRequested -= dataTransfer_DataRequested;
return base.OnNavigatingFrom(e);
}
//Note: This is the WinRT Xaml Toolkit version of the events, but the standard events will work the same way.