I am writing a Xamarin Forms app (.net standard 2.0). Currently it is only being developed for Android but it may be released for other OSs in future. The scenario I am trying to manage is this:
The user goes into a ContentPage with a single Entry
I give the Entry focus by using native Android code in a custom renderer:
if (e.NewElement != null && e.NewElement is CustomEntry)
{
CustomEntry customEntry = (CustomEntry)e.NewElement;
if(customEntry.GiveFocus)
{
//this messes up the onback behaviour - you have to press onback twice to exit the screen, once to get out of the hidden SIP
Control.RequestFocus();
}
}
I do not want the soft keyboard to pop up automatically. Therefore I have added the below line to the OnCreate of the MainActivity:
Window.SetSoftInputMode(SoftInput.StateAlwaysHidden);
The reason I am requesting focus in the custom renderer and not in the Xamarin Forms Entry is I could see the keyboard popup and then immediately disappear when I requested it in the Xamarin Forms control. I don't want the keyboard to appear as this app will be primarily used by users of industrial devices with a hardware keyboard, but the entry will need to have focus as the users will want to enter text into it straight away.
My problem is the user has to press the back button twice to exit the ContentPage in this scenario. Once to get out of the hidden keyboard (and the Entry loses focus) and then again to exit the page. I want to avoid this - they should be able to exit the page with only one click when the keyboard is hidden. Does anyone know how to resolve this? I have tried overriding OnKeyPreIme in the custom renderer as other answers have suggested but it doesn't appear to detect the back click.
You can use Hide Keyboard method when your entry get focused. It might solved your problem.
public interface IKeyboardHelper
{
void HideKeyboard();
}
For Android use :
public class DroidKeyboardHelper : IKeyboardHelper
{
public void HideKeyboard()
{
var context = Forms.Context;
var inputMethodManager = context.GetSystemService(Context.InputMethodService) as InputMethodManager;
if (inputMethodManager != null && context is Activity)
{
var activity = context as Activity;
var token = activity.CurrentFocus?.WindowToken;
inputMethodManager.HideSoftInputFromWindow(token, HideSoftInputFlags.None);
activity.Window.DecorView.ClearFocus();
}
}
}
For iOS :
public class iOSKeyboardHelper : IKeyboardHelper
{
public void HideKeyboard()
{
UIApplication.SharedApplication.KeyWindow.EndEditing(true);
}
}
Use Dependency Injection and call this method while your entry get focused.
Try to use below method for handling back button pressed event.
protected override bool OnBackButtonPressed()
{
// you can handle back button pressed event in Xamarin forms page
return base.OnBackButtonPressed();
}
I've (finally) worked it out. The key is not to override OnKeyPreIME but DispatchKeyEventPreIme instead. This allows you to intercept the 'Back' press. So, in my CustomRenderer I added this method:
public override bool DispatchKeyEventPreIme(KeyEvent e)
{
//if this is back press and the sip is not visible then we need to call the 'OnBack' method at the view model level
if(!SIPVisibleListener.IsSIPVisible && e.KeyCode == Keycode.Back)
{
if(XamarinFormsControl != null && XamarinFormsControl is IOnBackHandler)
{
((IOnBackHandler)XamarinFormsControl).GoBack();
}
}
return base.DispatchKeyEventPreIme(e);
}
IOnBackHandler is an interface I created to handle the back key press. SIPVisibleListener is based on an answer to this question: How do I Detect if Software Keyboard is Visible on Android Device?
Hopefully this will help someone.
Related
I'm using the Prism- dialog-service to show a dialog with a yes- and a no-button. This works fine. The user makes the choice and the calling page gets the dialogresult.
But it is also possible for the user to press the back-button if the dialog is present and the dialog disappears without any result to the calling page.
I know that I can override the OnBackButtonPressed-event in the MainActivity but this affects everywhere in my app.
It's important for me, that I can handle this behavior (suspend Back-Button or not) individually for each Dialog.
Therefore I'm looking for an event which will be fired if the back-button is pressed while the dialog is shown.
Similary with the OnBackButtonPressed-Event on a ContentPage.
forms project - pages:
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
.
.
IsBusy="{Binding IsBusy}">
android project - MainActivity:
public override void OnBackPressed()
{
var allNotBusy = true;
foreach (var fragment in this.GetFragmentManager().Fragments)
{
var contentPage = fragment.GetType().GetProperty("Page")?.GetValue(fragment) as ContentPage;
if (contentPage.IsBusy)
{
allNotBusy = false;
}
}
if (allNotBusy)
{
base.OnBackPressed();
}
}
I have an Entry and a Button:
<StackLayout>
<CustomViews:ChatEntryView x:Name="ChatEntry" />
<Button Text="Send" Command="SendCommand"/>
</StackLayout>
What I wanted to achieve here is that when the user starts types something on the Entry control and then presses the button, it should not hide the keyboard (or lose the Entry Focus).
The ChatEntryView here is just actually a custom view that inherits from the Entry control and what I did inside:
1.) Added an Unfocused handler
Unfocused += ChatEntryView_Unfocused;
void ChatEntryView_Unfocused(object sender, FocusEventArgs e)
{
this.Focus();
}
2.) Tried Handling on PropertyChanged
protected override void OnPropertyChanged(string propertyName = null)
{
this.Focus();
base.OnPropertyChanged(propertyName);
}
3.) Tried Handling on PropertyChanging
protected override void OnPropertyChanging(string propertyName = null)
{
this.Focus();
base.OnPropertyChanging(propertyName);
}
But all the three methods doesn't seem to work. I was able to do a work around on IOS by making a custom renderer and it's not very neat (by actually interfacing to the Control.ShouldEndEditing on IOS).
But my problem now is on Android, as I don't exactly know how to do this on Android and there's no Control.ShouldEndEditing (the interface on Android) that I can work with.
What happens by using the handlers above is that, the keyboard for the entry view still loses focus and then immediately gets focuses again which is very odd.
The keyboard pushes down (loses focus) and then pushes up (forced focus).
I know it's too late to anwser this question, but it might be helpful for someone else, I added this code to MainActivity, it might not be a neat solution, but works for me:
private bool _lieAboutCurrentFocus;
public override bool DispatchTouchEvent(MotionEvent ev)
{
var focused = CurrentFocus;
bool customEntryRendererFocused = focused != null && focused.Parent is CustomEntryRenderer_Droid;
_lieAboutCurrentFocus = customEntryRendererFocused;
var result = base.DispatchTouchEvent(ev);
_lieAboutCurrentFocus = false;
return result;
}
public override View CurrentFocus
{
get
{
if (_lieAboutCurrentFocus)
{
return null;
}
return base.CurrentFocus;
}
}
In a Xamarin Forms app, I am trying to create a custom Entry implementation that does not automatically display the soft keyboard when it is focused. The goal is to use one instance of this entry alongside other conventional entries on a page.
I am familiar with the recommended Xamarin Forms pattern for custom view rendering, and have successfully created both the Entry and its renderer, as follows:
public class BlindEntry : Entry
{
}
[assembly: ExportRenderer(typeof(BlindEntry), typeof(BlindEntryRenderer))]
public class BlindEntryRenderer : EntryRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<Entry> e)
{
base.OnElementChanged(e);
if (Control != null)
{
Control.FocusChange += Control_FocusChange;
}
}
private void Control_FocusChange(object sender, FocusChangeEventArgs e)
{
if (e.HasFocus)
{
// What goes here?
}
else
{
// What goes here?
}
}
}
To show and hide the soft keyboard, I imagine one of the recommendations from this question will provide the solution, but there are many different opinions on which is the best approach. Also, even after choosing a suitable pattern, I am not clear how to access the required native Android APIs from within the above custom renderer.
For example, I know that I can obtain a reference to an InputMethodManager using the following call (from within an Activity), but it is not obvious how to reference the containing activity from inside the renderer:
var imm = GetSystemService(InputMethodService)
Thanks, in advance, for your suggestions.
Tim
Try this instead inside OnElementChanged():
Control.InputType = Android.Text.InputTypes.Null;
This will prevent the keyboard from appearing when selecting the Entry without having to check its focus.
=== Edit ===
Turns out there is actually the ShowSoftInputOnFocus property available for doing exactly this.
Control.ShowSoftInputOnFocus = false;
Is there any way to know when the 'back' button event on the 'Android phone' is pressed? I'd like to exit the game and add few functionality to it when this button is pressed in Xamarin.Forms.
I googled a bit regarding this, but I got articles regarding Xamarin.Android Back button but not for Xamarin.Forms.
As I am relatively new to Xamarin.Forms, please help me out
public override void OnBackPressed()
{
//base.OnBackPressed();
}
Same thing I want in Xamarin.Forms. Need some assistance, guys.
If you mean Xamarin.Forms by "Xamarin Cross Platform", there is a OnBackButtonPressed event that you can use. As seen on that documentation:
Event that is raised when the hardware back button is pressed. This
event is not raised on iOS.
Simply override this event on your NavigationPage and you're ready to go:
protected override bool OnBackButtonPressed()
{
// Do your magic here
return true;
}
Good luck!
In my xamarin forms app you need to find the NavigationStack of the current Page if you are using master page:
public bool DoBack
{
get
{
MasterDetailPage mainPage = App.Current.MainPage as MasterDetailPage;
if (mainPage != null)
{
bool doBack = mainPage.Detail.Navigation.NavigationStack.Count > 1 || mainPage.IsPresented;
//top level of page and the Master menu isn't showing
if (!doBack)
{
// don't exit the app only show the Master menu page
mainPage.IsPresented = true;
return false;
}
else
{
return true;
}
}
return true;
}
}
I'm building a mobile AIR app (Android & IOS) with Adobe Flash Builder 4.6 and I'm having this annoying problem.
Because I want to 'catch' the back-key on Android devices I added the following code to my main class:
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDown);
private function keyDown(k:KeyboardEvent):void {
if(k.keyCode == Keyboard.BACK) {
backClicked(); // function handling the back-action, not important
k.preventDefault();
}
Now somewhere else - nested in some classes - I've got a textfield:
TF = new TextField();
TF.type = TextFieldType.INPUT;
But when I set focus on the textfield the soft keyboard does appear, but I can't type a single character. When I disable the keylistener: no problem.
Seems like the listener is overriding my input field. Is there any workaround on this?
I have also implemented the back button functionality for my mobile apps , but i used to register keydown event only when my particular view is activated and removed the registered when view get deactivated.
in <s:view ....... viewActivate ="enableHardwareKeyListeners(event)" viewDeactivate="destroyHardwareKeyListeners(event)">
// add listener only for android device
if (Check for android device) {
NativeApplication.nativeApplication.addEventListener(KeyboardEvent.KEY_DOWN, handleHardwareKeysDown, false, 0);
NativeApplication.nativeApplication.addEventListener(KeyboardEvent.KEY_UP, handleHardwareKeysUp, false, 0);
this.setFocus();
}
private function destroyHardwareKeyListeners(event:ViewNavigatorEvent):void
{
if (NativeApplication.nativeApplication.hasEventListener(KeyboardEvent.KEY_DOWN))
NativeApplication.nativeApplication.removeEventListener(KeyboardEvent.KEY_DOWN, handleHardwareKeysDown);
if (NativeApplication.nativeApplication.hasEventListener(KeyboardEvent.KEY_UP))
NativeApplication.nativeApplication.removeEventListener(KeyboardEvent.KEY_UP, handleHardwareKeysUp);
}
private function handleHardwareKeysDown(e:KeyboardEvent):void
{
if (e.keyCode == Keyboard.BACK) {
e.preventDefault();
// your code
} else {
}
}
private function handleHardwareKeysUp(e:KeyboardEvent):void
{
if (e.keyCode == Keyboard.BACK)
e.preventDefault();
}
May this can help you.