I have three fragments in a view pager:
A -> B -> C
I would like to get the strings of my two edittexts in Fragment A on swipe to Fragment B to show them in Fragment B. The edittext data may be changed up until the swipe.
Someone has suggested listening for typing and sending data after each one, but the callbacks I know for that change state EVERY key click (which can be expensive). How do I this without using buttons, since their right next to each other, for a more delightful experience?
You can check the data of the EditText on swipe ; if it's not null, then you can send it to any other fragment using Bundle since you are dealing with fragments
With help from #I. Leonard I found a solution here.
It was deprecated so I used the newer version. I put the below code in my fragment class because I needed access to the data without complicating things. It works like a charm!
On the page listener callback, I suggest, calling an interface for inter-fragment communication to do your actions on your home activity or to call the appropriate fragment that can do the work, from the activity.
// set content to next page on scroll start
vPager = (ViewPager) getActivity().findViewById(R.id.viewpager);
vPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
}
#Override
public void onPageScrollStateChanged(int state) {
if (state == ViewPager.SCROLL_STATE_SETTLING) {
// ViewPager is slowing down to settle on a page
if (vPager.getCurrentItem() == 1) {
// The page to be settled on is the second (Preview) page
if (!areFieldsNull(boxOne.getText().toString(), boxTwo.getText().toString()))
// call interface method in view pager activity using interface reference
communicator.preview(boxOne.getText().toString(), boxTwo.getText().toString());
}
}
}
});
Related
I am using a CellTable to display results of a query and I need these results to be shown as (html) links. I would like to react to a click on these links. So far, I had implemented it like this:
// ClickHandler on CellTable
cellTable.addCellPreviewHandler(new Handler<OperationalItemMultipleSearchRowData>() {
#Override
public void onCellPreview(CellPreviewEvent<OperationalItemMultipleSearchRowData> event) {
boolean isClick = "click".equals(event.getNativeEvent().getType());
if (isClick)
AdminUtils.EVENT_BUS.fireEvent(new SimpleSearchEvent(event.getValue().getName()));
}
});
The Problem is that this reacted to a Click on the whole row instead of the link. Due to architectural restrictions, the link itself is not a real html link, but a SafeHtml link that leads nowhere. I just needed the look&feel of a Link:
Column<OperationalItemMultipleSearchRowData, SafeHtml> nameColumn = new Column<OperationalItemMultipleSearchRowData, SafeHtml>(new SafeHtmlCell()) {
#Override
public SafeHtml getValue(final OperationalItemMultipleSearchRowData object) {
return new SafeHtml() {
#Override
public String asString() {
return "" + object.getName() + "";
}
};
}
};
How can I react to a click on this link only ? (instead of the whoel row)
Is there a more elegant way to implement this ?
Cheers
As with any other use of event delegation, the basic idea is to find walk up the hierarchy starting from the target of the event up until you find the link element you're looking for, or some other element that signals the search is over and the click was targetted outside the link (e.g. you reached the cell, the row or the table).
That being said, I think you should merge your behavior inside a specific Cell implementation rather than using a CellPreviewHandler (copy/paste the ActionCell or TextButtonCell as a starting point).
As a side note, I also believe you should not use a link when you're not actually linking anywhere, or try to provide a target for the link if the behavior is the one of a link (that way, right-clicking, middle-clicking or ctrl-clicking will Just Workâ˘). If you want the look of a link (without the "feel"), then just use an ActionCell or TextButtonCell and style it accordingly.
I'm creating a CRUD application that store data in a local h2 DB. I'm pretty new to JavaFX. I've created a TabPane to with 3 Tab using an jfxml created with Scene Builder 2.0. Each Tab contains an AncorPane that wrap all the controls: Label, EditText, and more. Both the TabPane and the Tabs are managed using one controller. This function is used to create and to update the data. It's called from a grid that display all the data. A pretty basic CRUD app.
I'm stuck in the validation phase: when the user change the tab, by selecting another tab, it's called a validation method of the corresponding tab. If the validation of the Tab fails, I want that the selection remains on this tab.
To achieve this I've implemented the following ChangeListener on the SelectionModel of my TabPane:
boolean processingTabValidationOnChange = false;
tabPane.getSelectionModel().selectedIndexProperty().addListener(new ChangeListener<Number>() {
#Override
public void changed(ObservableValue<? extends Number> ov, Number t, Number t1) {
if (processingTabValidationOnChange == false) {
boolean success;
switch (t.intValue()) {
case 0: success = validationTab1Passed();
break;
case 1: success = validationTab2Passed();
break;
case 1: success = validationTab3Passed();
break;
default: success = false;
}
if (success == false) {
processingTabValidationOnChange = true;
// select the previous tab
tabPane.getSelectionModel().select(t.intValue());
processingTabValidationOnChange = false;
}
}
}
});
I'm not sure that this is the right approach because:
The event changed is fired two times, one for the user selection and one for the .select(t.intValue()). To avoid this I've used a global field boolean processingTabValidationOnChange... pretty dirty I know.
After the .select(t.intValue()) the TabPane displays the correctly Tab as selected but the content of the tab is empty as if the AnchorPane was hidden. I cannot select again the tab that contains the errors because it's already selected.
Any help would be appreciated.
Elvis
I would approach this very differently. Instead of waiting for the user to select a different tab, and reverting if the contents of the current tab are invalid, prevent the user from changing tabs in the first place.
The Tab class has a disableProperty. If it is set to true, the tab cannot be selected.
Define a BooleanProperty or BooleanBinding representing whether or not the data in the first tab is invalid. You can create such bindings based on the state of the controls in the tab. Then bind the second tab's disableProperty to it. That way the second tab automatically becomes disabled or enabled as the data in the first tab becomes valid or invalid.
You can extend this to as many tabs as you need, binding their properties as the logic dictates.
Here's a simple example.
Update: The example linked above is a bit less simple now. It will dynamically change the colors of the text fields depending on whether the field is valid or not, with validation rules defined by bindings in the controller. Additionally, there are titled panes at the top of each page, with a title showing the number of validation errors on the page, and a list of messages when the titled pane is expanded. All this is dynamically bound to the values in the controls, so it gives constant, clear, yet unobtrusive feedback to the user.
As I commented to the James's answer, I was looking for a clean solution to the approach that I've asked. In short, to prevent the user to change to a different tab when the validation of the current tab fails. I proposed a solution implementing the ChangeListener but, as I explained: it's not very "clean" and (small detail) it doesn't work!
Ok, the problem was that the code used to switch back the previous tab:
tabPane.getSelectionModel().select(t.intValue());
is called before the process of switching of the tab itself it's completed, so it ends up selected... but hidden.
To prevent this I've used Platform.runLater(). The code .select() is executed after the change of tab. The full code becomes:
//global field, to prevent validation on .select(t.intValue());
boolean skipValidationOnTabChange = false;
tabPane.getSelectionModel().selectedIndexProperty().addListener(new ChangeListener<Number>() {
#Override
public void changed(ObservableValue<? extends Number> ov, Number t, Number t1) {
if (skipValidationOnTabChange == false) {
boolean success;
switch (t.intValue()) {
case 0:
success = validationTab1Passed();
break;
case 1:
success = validationTab2Passed();
break;
case 1:
success = validationTab3Passed();
break;
default:
success = false;
}
if (success == false) {
Platform.runLater(new Runnable() {
#Override
public void run() {
skipValidationOnTabChange = true;
tabPane.getSelectionModel().select(t.intValue());
skipValidationOnTabChange = false;
}
});
}
}
}
});
Anyway, if anyone has a better solution to accomplish this, you're welcome. In example using a method like consume() to prevent the tab to be selected two times. This way I can eliminated the global field skipValidationOnTabChange.
Elvis
I needed to achieve the similar thing. I've done this by changing the com.sun.javafx.scene.control.behavior.TabPaneBehaviour class by overriding selectTab method:
class ValidatingTabPaneBehavior extends TabPaneBehavior {
//constructors etc...
#Override
public void selectTab(Tab tab) {
try {
Tab current = getControl().getSelectionModel().getSelectedItem();
if (current instanceof ValidatingTab) {
((ValidatingTab) current).validate();
}
//this is the method we want to prevent from running in case of error in validation
super.selectTab(tab);
}catch (ValidationException ex) {
//show alert or do nothing tab won't be changed
}
}
});
The ValidatingTab is my own extension to Tab:
public class ValidatingTab extends Tab {
public void validate() throws ValidationException {
//validation
}
}
This is the "clean part" of the trick. Now we need to place ValidatingTabPaneBehavior into TabPane.
First you need to copy (!) the whole com.sun.javafx.scene.control.skin.TabPaneSkin to the new class in order to change its constructor. It is quite long class, so here is only the part when I switch the Behavior class:
public class ValidationTabPaneSkin extends BehaviorSkinBase<TabPane, TabPaneBehavior> {
//copied private fields
public ValidationTabPaneSkin(TabPane tabPane) {
super(tabPane, new ValidationTabPaneBehavior(tabPane));
//the rest of the copied constructor
}
The last thing is to change the skin in your tabPane instance:
tabPane.setSkin(new ValidationTabPaneSkin(tabPane));
I have built a GWT (2.5) web application that, among other things, uses a DataGrid. I have used addDomHandler to add a DoubleClickEvent to select a row and perform an action, and it works great on the desktop. However, when I run the web application on a touch device, the double click zooms the screen instead. Is there are proper way to handle that? I would prefer to override the default behavior of zooming, but I have no idea where to begin. I suppose a long press might be more appropriate, but I have no idea where to begin with that either.
The code:
_dataGrid.addDomHandler(new DoubleClickHandler() {
#Override
public void onDoubleClick(DoubleClickEvent event) {
// Do something exciting here!
}
}, DoubleClickEvent.getType());
The only idea I have it that stopping the propagation of the DOM event may prevent the default zoom behavior.
Although I'd be curious is it registers as a double-click event at all on a touchscreen device. Would be worth trying just putting the handler on Root and seeing if you can even catch the event.
Also try this: just have your application catch -any- DOM event and simply write the name out somehow. That way you, should find out what event is triggering (might be one for long touch!) and can write a handler for that.
OK, I found a solution, but it's probably pretty unique to my situation. What I did was keep the double click handler and I also implemented a slow double click. In other words, if you select the same row of the DataGrid twice in sequence, no matter how fast you do it, then the application interprets that as a double click. Here is the code:
result.addDomHandler(new ClickHandler() {
#Override
public void onClick(ClickEvent event) {
Scheduler.get().scheduleDeferred(new Command() {
public void execute () {
if (result.isDoubleTap()) {
// Do the same thing a a double click.
}
}
});
}});
I had a problem with the click handler being fired before the selection change handler, so I had to defer the processing of the click event with the Scheduler. The "result" is a Composite that contains the DataGrid and some other stuff, and in each "result" I store the last selected item in a private variable. Then in IsDoubleTap() all I do is see if the current selection is the same as the last one:
public boolean isDoubleTap() {
boolean result = false;
String selected = getSelected();
if (_lastSelect != null && selected != null && selected.equals(_lastSelect))
result = true;
_lastSelect = selected;
return result;
}
So effectively if you do a normal double click or a slow double click you get the same action. I'm just glad that while I use this result object many places, it is the only place that I use a double click. And I would REALLY like to have a conversion with the committee that decided overriding standard double click behavior with a touch device was a GOOD thing.
Im working on a MVVM Windows phone app that displays weather info.
When the app loads up it opens MainPage.xaml. It makes a call the the service to get weather info and binds that data to the UI. Both Fahrenheit and Celcius info are returned but only one is displayed.
On the setting page, the user can select to view the temp in either Fahrenheit or Celcius.
The user can change this setting at any time and its stored in IsolatedStorageSettings.
The issue Im having is this:
when the user navigates to the Settings page and changes their preference for either Fahrenheit or Celcius, this change is not reflected on the main page.
This issue started me thinking about this in a broader context. I can see this being an issue in ANY MVVM app where the display depends on some setting in IsolatedStorage. Any time any setting in the IsoStore is updated, how does the ViewModels know this? When I navigate back in the NavigationStack from the settings page back to MainPage how can I force a rebind of the page?
The data in my model hasnt changed, only the data that I want to display has changed.
Am I missing something simple here?
Thanks in advance.
Alex
Probably you have code like this:
public double DisplayTemperature
{
get { return (IsCelsium) ? Celsium : Fahrenheit; }
}
And IsCelsium is:
public double IsCelsium
{
get { return (bool)settings["IsCelsium"]; }
set { settings["IsCelsium"] = value; }
}
So you need to add NotifyPropertyChanged event to notify UI to get new values from DisplayTemperature property:
public double IsCelsium
{
get { return (bool)settings["IsCelsium"]; }
set
{
settings["IsCelsium"] = value;
NotifyPropertyChanged("DisplayTemperature");
}
}
Take a look at Caliburn Micro. You could implement something similar or use CM itself. When using CM I don't even think about this stuff, CM makes it so simple.
When your ViewModel inherits from Screen there are life-cycle events that fire that you can override. For example, OnInitialize fires the very first time the ViewModel is Activated and OnActivate fires every time the VM is activated. There's also OnViewAttached and OnViewLoaded.
These methods are the perfect place to put logic to populate or re-populate data.
CM also has some special built in features for allowing one to easily tombstone a single property or an entire object graph into Iso or phone state.
ok, so Ive come up with a solution. Before I get to it, let me provide some background. The app that Im working on uses both MVVM Light and WP7Contrib. That being the case, I am using Funq for DI and the MVVMLight Toolkit. After I posted my initial question, I gave the question a bit more thought. I remembered a video that I watched a while back from MIX2011 called Deep Dive MVVM with Laurent Bugnion
http://channel9.msdn.com/Events/MIX/MIX11/OPN03
In it, he talks about just this problem (view models not living at the same time) on Windows Phone. The part in question starts around the 19 minute mark.
Anyway, after I remembered that and realized that the ViewModel locator is exposed in App.xaml, this became a trivial problem to solve. When the user changes the Fahrenheit/Celcius option on the setting page, I simply get a reference to the MainViewModel via the ViewModelLocator and reset the collection that is bound to the UI thus causing the bindings to update.
public bool AddOrUpdateValue(string Key, Object value)
{
bool valueChanged = false;
// If the key exists
if (settings.Contains(Key))
{
// If the value has changed
if (settings[Key] != value)
{
// Store the new value
settings[Key] = value;
valueChanged = true;
}
}
// Otherwise create the key.
else
{
settings.Add(Key, value);
valueChanged = true;
}
return valueChanged;
}
public bool ImperialSetting
{
get
{
return GetValueOrDefault<bool>(ImperialSettingKeyName, ImperialSettingDefault);
}
set
{
if (AddOrUpdateValue(ImperialSettingKeyName, value))
{
Save();
RaisePropertyChanged("ImperialSettingText");
var vml = new ViewModelLocator();
vml.MainViewModel.Cities = (App.Current as App).Cities;
}
}
}
It was a mistake on my part not to realize that I could get access to the viewModel via the ViewModelLocator. Hopefully this post saves someone else the time I burned on this issue.
I try to implement simple touch event handling on Blackberry 9550 emulator, but it doesn't work. Actually, touchEvent never gets called, 'cos no text ever appears in the console. Also, I get an annoying "Full Menu" which appears on touching the screen.
Here's the code:
package mypackage;
import net.rim.device.api.system.Bitmap;
import net.rim.device.api.system.EventInjector.TouchEvent;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.VirtualKeyboard;
import net.rim.device.api.ui.container.MainScreen;
public class MyScreen extends MainScreen
{
public MyScreen()
{
super(NO_SYSTEM_MENU_ITEMS);
getScreen().getVirtualKeyboard().setVisibility(VirtualKeyboard.HIDE_FORCE);
add(new HandleTouch());
}
class HandleTouch extends Field {
protected void layout(int width, int height) {
setExtent(width, height);
}
public void paint(Graphics graphics) {
graphics.drawBitmap(0, 0, this.getWidth(), this.getHeight(), Bitmap.getBitmapResource("bg.png"), 0, 0);
}
public boolean isFocusable() { return true;}
protected boolean touchEvent(TouchEvent message) {
switch( message.getEvent() ) {
case TouchEvent.CLICK:
System.out.println("----------------------------->CLICK");
return true;
case TouchEvent.DOWN:
System.out.println("----------------------------->DOWN");
return true;
case TouchEvent.MOVE:
System.out.println("----------------------------->MOVE");
return true;
}
System.out.println("PRINT ME SOMETHING IN ANY CASE");
return false;
}
public HandleTouch() {
}
}
}
1). First of all, with this code
protected void layout(int width, int height) {
setExtent(width, height);
}
you are actually setting a VERY large size of the field. This because the BB UI framework passes max available/possible dimentions to layout(int width, int height) so the field should use some part within the passed values. In this specific case the width will be the width of the display (360 px) and the height is the max possible height of the VerticalFieldManager (the one your are adding screen fields to, it is implicitly present in the screen's internals) (1073741823 px). So, finally this may result in a very large Bitmap object that is required with the field in order to be painted and you can get an uncaught error "Bitmap is too large" (I did on Storm 9530).
So, the layout() should use some relatively small values, e.g.:
protected void layout(int width, int height) {
setExtent(Math.min(width, 360), Math.min(height, 480));
}
2).
Actually, touchEvent never gets called
Well, actually it does get called. To see that you should simply touch (versus click). Left button of the mouse simulates clicks (a sequence of TouchEvent.DOWN > TouchEvent.CLICK > TouchEvent.UNCLICK > TouchEvent.UP), right button simulates touches (a sequence of TouchEvent.DOWN > TouchEvent.UP).
3).
Also, I get an annoying "Full Menu" which appears on touching the screen.
This is because your field does not consume TouchEvent.UNCLICK event. For instance, with this code your field will not show the popup:
protected boolean touchEvent(TouchEvent message) {
return true;
}
But, that is a bad solution for the popup. It is better to understand what really causes the popup. If TouchEvent.UNCLICK event is not consumed then BB UI framework calls getContextMenu(int instance) and makeContextMenu(ContextMenu contextMenu, int instance) methods of the field. So in order to disable the popup (which is actually a ContextMenu created by the getContextMenu(int instance) you should override the getContextMenu(int instance) to be smth like this:
public ContextMenu getContextMenu(int instance) {
// just in case check if a context menu is requested
// in order not to disable other types of menu
boolean isContextMenu = (Menu.INSTANCE_CONTEXT == instance);
return isContextMenu ? null : super.getContextMenu(instance);
}
4). Finally I'd recommend to not change native/default behavior of touchEvent(TouchEvent message) method. You can just watch/log it, but don't change (always call its super version). This is because touch events handling is more complicated than it may look at first. It is very easy to get a tricky bug here. I do believe most programmers should not change the native behavior of touchEvent(TouchEvent message) unless they really want to create some custom UI component to work with touch gestures. Normally they just want to react on a click (to behave as a ButtonField), however for that you can simply override navigationClick(int status, int time) or navigationUnclick(int status, int time). The BB UI framework will call those methods when user clicks your field on a touch screen.
I would like to add extra info to Arhimed's answer, since this seems to be a landing page for googling touch events...
My experiences are not to contradict him, but to add possible solutions for future readers. I am using BB OS 5.0. My experiences have been with the Storm simulator, and a Torch device. My app was originally written for OS 4.5, so it might be running in some sort of compatibility mode.
1) As explained in his point 4, a Touch Event gets passed along to a Navigation Click event, if touchEvent(TouchEvent) returns false. If navigationClick(int, int) returns false, this prompts the system to display a ContextMenu.
2) On my system, I could not find a method getContextMenu(int). So I could not test his point 3. I presume this gets added in BB6 or later.
3) I did find getContextMenu() - i.e. it takes no parameters. I tried to override that method to return null.
The strange thing is that this method only gets called after the initial context menu popup is shown! The initial context menu popup (?) gets shown, with a button on it for "Full Menu". When that button is pressed, this method gets called, and can be used to populate the MainMenu that appears. ... strange...
However, it means that overriding that method did not solve my problem.
4) I was unable to get a solution by returning true in touchEvent(TouchEvent). I agree that this would have been bad form (hack), but I have learnt to hack a lot on the BB platform. However, scrolling list fields need to have the touch event passed up, so that the scroll works.
5) Eventually I found something similar to the OP's problem with TouchEvent.UNCLICK. It has taken me 18 months to find the method navigationUnClick(int, int). Similar to my point 1 above, an unhandled UNCLICK becomes a navigationUnClick(int, int) call, which can also lead to the context menu being shown.
So by adding similar logic to both navigationClick(int, int) & navigationUnClick(int, int), I was able to get my lists & touches to interact nicely.
This is just supplemental info, that may add to the accepted anser.