I want my app to change different parts of the UI when the resolution is big enough and is on landscape mode, and detect changes while the app is running (screen rotation on a mobile device, for instance).
I know that I should have an event listen to the screen resolution (which can be obtained via javascript), but I don't know how to do this. How do I hang an event on a always refreshing value?
You want Window.addResizeHandler
Window.addResizeHandler(new ResizeHandler() {
#Override
public void onResize(ResizeEvent event) {
yourCustomLayoutAdjustmentMethod(event.getHeight(), event.getWidth());
}
});
No JavaScript required!
with MGWT library (http://code.google.com/p/mgwt/) :
import these classes
import com.googlecode.mgwt.dom.client.event.orientation.OrientationChangeEvent;
import com.googlecode.mgwt.dom.client.event.orientation.OrientationChangeEvent.ORIENTATION;
import com.googlecode.mgwt.dom.client.event.orientation.OrientationChangeHandler;
import com.googlecode.mgwt.ui.client.MGWT;
define an orientation handler
class MyOrientationChangeHandler implements OrientationChangeHandler {
#Override
public void onOrientationChanged(OrientationChangeEvent event) {
switch (event.getOrientation()) {
case LANDSCAPE:
// handle landscape orientation
return;
case PORTRAIT:
// handle portrait orientation
return;
}
}
}
add your handler
MGWT.addOrientationChangeHandler(new MyOrientationChangeHandler ());
Related
I have found that on iOS, OnAppearing is called when the page literally appears on the screen, whereas on Android, it's called when it's created.
I'm using this event to lazily construct an expensive to construct view but obviously the Android behaviour defeats this.
Is there some way of knowing on Android when a screen literally appears on the screen?
You can use the event:
this.Appearing += YourPageAppearing;
Otherwise, you should use the methods of the Application class that contains the lifecycle methods:
protected override void OnStart()
{
Debug.WriteLine ("OnStart");
}
protected override void OnSleep()
{
Debug.WriteLine ("OnSleep");
}
protected override void OnResume()
{
Debug.WriteLine ("OnResume");
}
On Android, Xamarin.Forms.Page.OnAppearing is called immediately before the page's view is shown to user (not when the page is "created" (constructed)).
If you want an initial view to appear quickly, by omitting an expensive sub-view, use a binding to make that view's IsVisible initially be "false". This will keep it out of the visual tree, avoiding most of the cost of building it. Place the (invisible) view in a grid cell, whose dimensions are constant (either in DPs or "*" - anything other than "Auto".) So that layout will be "ready" for that view, when you make it visible.
APPROACH 1:
Now you just need a binding in view model that will change IsVisible to "true".
The simplest hack is to, in OnAppearing, fire an action that will change that variable after 250 ms.
APPROACH 2:
The clean alternative is to create a custom page renderer, and override "draw".
Have draw, after calling base.draw, check an action property on your page.
If not null, invoke that action, then clear it (so only happens once).
I do this by inheriting from a custom page base class:
XAML for each of my pages (change "ContentPage" to "exodus:ExBasePage"):
<exodus:ExBasePage
xmlns:exodus="clr-namespace:Exodus;assembly=Exodus"
x:Class="YourNamespace.YourPage">
...
</exodus:ExBasePage>
xaml.cs:
using Exodus;
// After creating page, change "ContentPage" to "ExBasePage".
public partial class YourPage : ExBasePage
{
...
my custom ContentPage. NOTE: Includes code not needed for this, related to iOS Safe Area and Android hardward back button:
using Xamarin.Forms;
using Xamarin.Forms.PlatformConfiguration.iOSSpecific;
namespace Exodus
{
public abstract partial class ExBasePage : ContentPage
{
public ExBasePage()
{
// Each sub-class calls InitializeComponent(); not needed here.
ExBasePage.SetupForLightStatusBar( this );
}
// Avoids overlapping iOS status bar at top, and sets a dark background color.
public static void SetupForLightStatusBar( ContentPage page )
{
page.On<Xamarin.Forms.PlatformConfiguration.iOS>().SetUseSafeArea( true );
// iOS NOTE: Each ContentPage must set its BackgroundColor to black or other dark color (when using LightContent for status bar).
//page.BackgroundColor = Color.Black;
page.BackgroundColor = Color.FromRgb( 0.3, 0.3, 0.3 );
}
// Per-platform ExBasePageRenderer uses these.
public System.Action NextDrawAction;
/// <summary>
/// Override to do something else (or to do nothing, i.e. suppress back button).
/// </summary>
public virtual void OnHardwareBackButton()
{
// Normal content page; do normal back button behavior.
global::Exodus.Services.NavigatePopAsync();
}
}
}
renderer in Android project:
using System;
using Android.Content;
using Android.Views;
using Android.Graphics;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
using Exodus;
using Exodus.Android;
[assembly: ExportRenderer( typeof( ExBasePage ), typeof( ExBasePageRenderer ) )]
namespace Exodus.Android
{
public class ExBasePageRenderer : PageRenderer
{
public ExBasePageRenderer( Context context ) : base( context )
{
}
protected override void OnElementChanged( ElementChangedEventArgs<Page> e )
{
base.OnElementChanged( e );
var page = Element as ExBasePage;
if (page != null)
page.firstDraw = true;
}
public override void Draw( Canvas canvas )
{
try
{
base.Draw( canvas );
var page = Element as ExBasePage;
if (page?.NextDrawAction != null)
{
page.NextDrawAction();
page.NextDrawAction = null;
}
}
catch (Exception ex)
{
// TBD: Got Disposed exception on Android Bitmap, after rotating phone (in simulator).
// TODO: Log exception.
Console.WriteLine( "ExBasePageRenderer.Draw exception: " + ex.ToString() );
}
}
}
}
To do some action after the first time the page is drawn:
public partial class YourPage : ExBasePage
{
protected override void OnAppearing()
{
// TODO: OnPlatform code - I don't have it handy.
// On iOS, we call immediately "DeferredOnAppearing();"
// On Android, we set this field, and it is done in custom renderer.
NextDrawAction = DeferredOnAppearing;
}
void DeferredOnAppearing()
{
// Whatever you want to happen after page is drawn first time:
// ((MyViewModel)BindingContext).ExpensiveViewVisible = true;
// Where MyViewModel contains:
// public bool ExpensiveViewVisible { get; set; }
// And your XAML contains:
// <ExpensiveView IsVisible={Binding ExpensiveViewVisible}" ... />
}
}
NOTE: I do this differently on iOS, because Xamarin Forms on iOS (incorrectly - not to spec) calls OnAppearing AFTER the page is drawn.
So I have OnPlatform logic. On iOS, OnAppearing immediately calls DeferredOnAppearing. On Android, the line shown is done.
Hopefully iOS will eventually be fixed to call OnAppearing BEFORE,
for consistency between the two platforms.
If so, I would then add a similar renderer for iOS.
(The current iOS implementation means there is no way to update a view before it appears a SECOND time, due to popping the nav stack.
instead, it appears with outdated content, THEN you get a chance
to correct it. This is not good.)
I set up an alarm to show a corresponding Notification. The PendingIntent of the Notification is used to start the Gluon App main class. To show a View other than the homeView, I call switchView(otherView) in the postInit method. OtherView is shown, but without AppBar. While it's possible to make the AppBar appear, I wonder if this is the right approach.
#Override
public void postInit(Scene scene) {
// additional setUp logic
boolean showReadingView = (boolean) PlatformProvider.getPlatform().getLaunchIntentExtra("showReadingView", false);
if (showReadingView) {
switchView(READING_VIEW);
}
}
When triggering anything related to the JavaFX thread from another thread, we have to use Platform.runLater().
Yours is a clear case of this situation: the Android thread is calling some pending intent, and as a result, the app is started again.
This should be done:
#Override
public void postInit(Scene scene) {
// additional setUp logic
boolean showReadingView = (boolean) PlatformProvider.getPlatform().getLaunchIntentExtra("showReadingView", false);
if (showReadingView) {
Platform.runLater(() -> switchView(READING_VIEW));
}
}
Is there any solution to detect the visibility of an Unity3D game? especially do some specific thing while it's switched to the foreground/background?
MonoBehaviours support two useful hooks:
OnApplicationFocus will be called any time the player gains or loses focus.
OnApplicationPause will be called any time the application is paused or unpaused. Note that it will only be paused if "run in background" is false in player settings, and that most code execution will stop until the app regains focus.
With the above caveats in mind, I usually prefer to use OnApplicationFocus, but both can be useful depending on what exactly you're trying to do.
As far as handling those events, you could make sure that some object in every scene is listening for them. Either attach some sort of singleton object that persists between scenes, or keep an object per scene that handles them appropriately.
Unity's scripting reference provides this example. By attaching this script to an object in some scene, it will throw up a GUI message while the game has lost focus:
public class Example : MonoBehaviour {
public bool paused;
void OnGUI() {
if (paused) {
GUI.Label(new Rect(100, 100, 50, 30), "Game paused");
}
}
void OnApplicationFocus(bool focusStatus) {
paused = focusStatus;
}
}
OnApplicationPause should be what you need.
Example (pulled directly from Unity docs for readability):
using UnityEngine;
using System.Collections;
public class Example : MonoBehaviour {
public bool paused;
void OnGUI() {
if (paused)
GUI.Label(new Rect(100, 100, 50, 30), "Game paused");
}
void OnApplicationPause(bool pauseStatus) {
paused = pauseStatus;
}
}
I am a beginner in java(fx).
How do you get the mouse location in x and y in JavaFX? I tried using AWT's MouseInfo(also imported it), but it's not working. I also saw the code for it in Ensembles(that dragging the ball-window in "advanced stage", that's what I need to do, drag my undecorated JavaFX stage), but it also doesn't work. I am using FXML with controller, and I guess that's the main problem. Should I switch back to the single-file simple JavaFX? I know FXML is better for laying out the UI, but I can't get many of such codes to work. Or do I need some other sort of code for my controller? Please give proper codes with comments wherever possible.
If you need a bit of my code to inspect, feel free to ask.
There are a few items in your question - I'll tackle them one at a time.
How do you get the mouse location in x and y in JavaFX?
Add a mouse event handler to the appropriate JavaFX component that you want to track the mouse location in. A JavaFX mouse event will report multiple different kinds of co-ordinates. The x and y co-ordinates are relative to the top left corner of the node whose location is being monitored. The sceneX and sceneY co-ordinates are relative to the scene's top left 0,0 co-ordinates. The screenX and screenY co-ordinates are relative to the top left 0,0 co-ordinates of the current screen.
These co-ordinates are documented in the MouseEvent documentation. There is extra information in understanding co-ordinate systems in the Node and Scene documentation.
import javafx.application.Application;
import static javafx.application.Application.launch;
import javafx.event.*;
import javafx.scene.*;
import javafx.scene.control.*;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.VBox;
import javafx.stage.*;
public class MouseLocationReporter extends Application {
private static final String OUTSIDE_TEXT = "Outside Label";
public static void main(String[] args) { launch(args); }
#Override public void start(final Stage stage) {
final Label reporter = new Label(OUTSIDE_TEXT);
Label monitored = createMonitoredLabel(reporter);
VBox layout = new VBox(10);
layout.setStyle("-fx-background-color: cornsilk; -fx-padding: 10px;");
layout.getChildren().setAll(
monitored,
reporter
);
layout.setPrefWidth(500);
stage.setScene(
new Scene(layout)
);
stage.show();
}
private Label createMonitoredLabel(final Label reporter) {
final Label monitored = new Label("Mouse Location Monitor");
monitored.setStyle("-fx-background-color: forestgreen; -fx-text-fill: white; -fx-font-size: 20px;");
monitored.setOnMouseMoved(new EventHandler<MouseEvent>() {
#Override public void handle(MouseEvent event) {
String msg =
"(x: " + event.getX() + ", y: " + event.getY() + ") -- " +
"(sceneX: " + event.getSceneX() + ", sceneY: " + event.getSceneY() + ") -- " +
"(screenX: " + event.getScreenX()+ ", screenY: " + event.getScreenY() + ")";
reporter.setText(msg);
}
});
monitored.setOnMouseExited(new EventHandler<MouseEvent>() {
#Override public void handle(MouseEvent event) {
reporter.setText(OUTSIDE_TEXT);
}
});
return monitored;
}
}
I tried using AWT's MouseInfo(also imported it), but it's not working.
Don't do this. Mixing different graphical toolkits (for example Swing/AWT and JavaFX) is an advanced topic. In general, if you are writing a JavaFX application, avoid importing anything from the java.awt namespace and the javax.swing namespace. You only really need to use those if you have a large, existing Swing based application or framework that you need to inter-operate with your JavaFX application. In this case, you don't have that situation.
I also saw the code for it in Ensembles(that dragging the ball-window in "advanced stage", that's what I need to do, drag my undecorated JavaFX stage), but it also doesn't work.
I tried the Ensemble Advanced Stage sample and dragging that stage around worked for me.
Another sample for dragging an undecorated stage in JavaFX is in the answer to How to draw a clock with JavaFX 2? which has associated sample code. The method used to make the undecorated stage draggable for the clock sample is:
/** makes a stage draggable using a given node */
public static void makeDraggable(final Stage stage, final Node byNode) {
final Delta dragDelta = new Delta();
byNode.setOnMousePressed(new EventHandler<MouseEvent>() {
#Override public void handle(MouseEvent mouseEvent) {
// record a delta distance for the drag and drop operation.
dragDelta.x = stage.getX() - mouseEvent.getScreenX();
dragDelta.y = stage.getY() - mouseEvent.getScreenY();
byNode.setCursor(Cursor.MOVE);
}
});
byNode.setOnMouseReleased(new EventHandler<MouseEvent>() {
#Override public void handle(MouseEvent mouseEvent) {
byNode.setCursor(Cursor.HAND);
}
});
byNode.setOnMouseDragged(new EventHandler<MouseEvent>() {
#Override public void handle(MouseEvent mouseEvent) {
stage.setX(mouseEvent.getScreenX() + dragDelta.x);
stage.setY(mouseEvent.getScreenY() + dragDelta.y);
}
});
byNode.setOnMouseEntered(new EventHandler<MouseEvent>() {
#Override public void handle(MouseEvent mouseEvent) {
if (!mouseEvent.isPrimaryButtonDown()) {
byNode.setCursor(Cursor.HAND);
}
}
});
byNode.setOnMouseExited(new EventHandler<MouseEvent>() {
#Override public void handle(MouseEvent mouseEvent) {
if (!mouseEvent.isPrimaryButtonDown()) {
byNode.setCursor(Cursor.DEFAULT);
}
}
});
}
I am using FXML with controller, and I guess that's the main problem. Should I switch back to the single-file simple JavaFX? I know FXML is better for laying out the UI, but I can't get many of such codes to work.
Lack of understanding and familiarity with the underlying JavaFX APIs is probably your main problem rather than use of FXML. However the additional complexity fxml implies together with the lighter documentation and samples for it on the web may be contributing to your hardships. If use of FXML is making it difficult for you to understand how to get some JavaFX functions to work, I advise to stop using FXML for now. Code the logic by hand using the Java APIs and refer to the Oracle JavaFX tutorials and the Ensemble sample code when you encounter things which are difficult for you.
Once you are comfortable coding directly to the JavaFX API, switch back to using FXML for larger projects which contain many GUI elements. The FXML elements and attributes themselves are built almost completely upon reflection of the standard JavaFX APIs. So, if you understand the core JavaFX APIs, you also understand almost everything about FXML.
Please do not post follow up comments to this answer (as this answer is long enough as it is). If you have new questions, create a new question (one question per question).
What about using Robot for that purpose ?
http://docs.oracle.com/javase/1.5.0/docs/api/java/awt/Robot.html
Using Robots, it is different from posting event to AWT event queue. Events are generated in the native event queue. Actually, with Robot.mouseMove you will not only set mouse position and not only get position.
For getting mouse position, you may stick to MouseInfo
import java.awt.MouseInfo;
// get the mouse's position
Point p = MouseInfo.getPointerInfo().getLocation();
It's not working: are you with Mac ? Which is your version of JavaFX ? seems to be issues corrected for FX8. For mac only, you may use
com.sun.glass.ui.Robot robot =
com.sun.glass.ui.Application.GetApplication().createRobot();
// getPosition of the mouse in Mac
int x = robot.getMouseX();
int y = robot.getMouseY();
JavaFx 8 WindowEvent doesn't provide the (x,y) location of the mouse, unfortunately. I solved this (and it works fine) by using the AWT MouseInfo like this:
Tooltip t = new Tooltip();
Tooltip.install(yournode, t);
t.setOnShowing(ev -> {// called just prior to being shown
Point mouse = java.awt.MouseInfo.getPointerInfo().getLocation();
Point2D local = yournode.screenToLocal(mouse.x, mouse.y);
// my app-specific code to get the chart's yaxis value
// then set the text as I want
double pitch = yaxis.getValueForDisplay(local.getY()).doubleValue();
double freq = AudioUtil.pitch2frequency(pitch);
t.setText(String.format("Pitch %.1f: %.1f Hz %.1f samples", pitch, freq, audio.rate / freq));
});
In Blackberry I can navigate from one screen to the next screen, but I can't navigate back to the previous screen. Pressing the escape key in the emulator terminates the entire application. Is there any other key in the emulator to go to the previous screen or any code to navigate back? If you know please help me.
As Andrey said, there is a display stack, so if you push screens without popping them, they will stay in stack, so closing current screen, previous screen will be shown automattically, and if there is no prev. screen, application will close.
However it's not good to hold many screens in display stack, so you can implement kind of stack inside of screens, to handle navigation manually.
Abstract screen class for screen stack implementation:
public abstract class AScreen extends MainScreen {
Screen prevScreen = null;
void openScreen(AScreen nextScreen) {
nextScreen.prevScreen = this;
UiApplication.getUiApplication().popScreen(this);
UiApplication.getUiApplication().pushScreen(nextScreen);
}
void openPrevScreen() {
UiApplication.getUiApplication().popScreen(this);
if (null != prevScreen)
UiApplication.getUiApplication().pushScreen(prevScreen);
}
}
Sample first screen:
public class FirstScreen extends AScreen implements FieldChangeListener {
ButtonField mButton = null;
public FirstScreen() {
super();
mButton = new ButtonField("Go second screen", ButtonField.CONSUME_CLICK);
mButton.setChangeListener(this);
add(mButton);
}
public void fieldChanged(Field field, int context) {
if (mButton == field) {
openScreen(new SecondScreen());
}
}
}
Sample second screen:
public class SecondScreen extends AScreen implements FieldChangeListener {
ButtonField mButton = null;
public SecondScreen() {
super();
mButton = new ButtonField("Go first screen", ButtonField.CONSUME_CLICK);
mButton.setChangeListener(this);
add(mButton);
}
public void fieldChanged(Field field, int context) {
if (mButton == field) {
openPrevScreen();
}
}
public boolean onClose() {
openPrevScreen();
return true;
}
}
The BlackBerry maintains a stack of screens; the display stack.
Screens are popped onto the stack, and popped off the stack through the UiApplication in charge of them. Popping the last screen off the stack closes the application by default.
If you are running a UiApplication, named MyUiApplication, you can add the screen to the stack by calling pushScreen(new SomeScreen());
The screen, if derived from MainScreen, as most BlackBerry screens are, is created with the DEFAULT_CLOSE flag, meaning that the ESCAPE button on the BlackBerry will naturally close the screen, causing popScreen() to be called. You can, of course, call popScreen() following any keypress or trackwheel/trackball click. The screen can also call close() on itself, which has the same result; the screen is popped off the stack, returning the application to the previous screen, or terminating the application if the last screen is popped off the display stack.
If the application is not created as a UiApplication, or if the screen was initially pushed onto the display stack from a non-UI thread (such as a background thread), then one must make sure that the call to close the screen is also done from the UI thread. This can be done by making sure that the eventLock is taken on the Application class prior to performing any UI operation (one would typically call invokeLater as well, in this situation).
If the original screen was popped onto the stack as a global screen (modeless, on top of all other screens), then it must be popped off the stack using something like:
Ui.getUiEngine().dismissStatus(this);
In any case, overriding onClose() and close() of the derived Screen will allow you to trap the occurring exception for debugging and further analysis.