I'm working with java me, I built an app using forms displayables. I'm trying to switch to other forms, based on the user's input in a textfield item. For example, I want the user to be able to type in the number "1" in the textfield and then be taken to form1 or type in "2" and be taken to form2 etc.
What's the code to do this?
Here's what I did but it's not working as expected:
form.setItemStateListener(new ItemStateListener() {
public void itemStateChanged(Item item) {
if (item == TextField) {
if ("1".equals(TextField.getString())) {
switchDisplayable(null, form1);
}
}
}
I've done as adviced. I added a command to the textfield item and listen on it to read textfield contents and then compare the contents as a string, to switch forms. See my code below, still not working. I think maybe there's something I'm missing or my logic is not right.
form.setCommandListener(new CommandListener() {
public void commandAction(Command command, Displayable displayable) {
if (command == getTextFieldItemCommand()) {
if ("1".equals(TextField.getString())) {
switchDisplayable(null, form1);
} else if ("2".equals(TextField.getString())){
switchDisplayable(null, form2);
}
}
}
It looks like you expect method itemStateChanged to be invoked when it feels convenient to you, like at every character entry in the text field.
Above expectation is wrong, specified behavior is explained in API javadocs:
It is up to the device to decide when it considers a new value to have been entered into an Item... In general, it is not expected that the listener will be called after every change is made...
Given above, using itemStateChanged the way you want makes very little sense, consider changing design of your MIDlet.
I for one would probably just add a command Go and command listener to the form or text field and read text field contents when user invokes that command to find out which displayable they want to switch to.
Related
I have this situation where I have a constraint layout. Within it lies two views. An ImageView and a TextView. When either of these Views is clicked, I want both to produce a feedback (text color change for textview and drawable tint in imageview) but I can't seem to think of a way to do these unless I put them inside another viewgroup.
Can someone show me how this could be done in constraint Layout? thank you.
Take a look at performClick().
performClick
boolean performClick ()
Call this view's OnClickListener, if it is defined. Performs all normal actions associated with clicking: reporting accessibility event, playing a sound, etc.
The idea is that when one view is clicked, your code will call performClick() on the other view. You will have to make sure that you inhibit any duplication of actions if the two views do the same function.
Other than doing this in code, I don't know of a way using just XML. There is the concept of a Group in ConstraintLayout but that just a way to control the visibility of the members of the group and does not extend to other properties.
I would use another enclosing view group unless you have a requirement not to. I just seems easier.
Use Group concept in ConstraintLayout refer: https://developer.android.com/reference/android/support/constraint/Group ,https://riggaroo.co.za/constraintlayout-guidelines-barriers-chains-groups/ ,
in java
Group group = findViewById(R.id.group);
int refIds[] = group.getReferencedIds();
for (int id : refIds) {
findViewById(id).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// your code here.
}
});
}
Kotlin:
fun Group.setAllOnClickListener(listener: View.OnClickListener?) {
referencedIds.forEach { id ->
rootView.findViewById<View>(id).setOnClickListener(listener)
}
}
Then call the function on the group:
group.setAllOnClickListener(View.OnClickListener {
// your code here.
})
Suppose I want to pass one object (reference) through several pages. I can navigate and pass parameters via Frame.Navigate(typeof(FirstPage), object). But how to pass the reference back on back press properly?
protected override void OnNavigatedTo(NavigationEventArgs e) {
if (e.Parameter is SomeClass) {
this.someObject = (SomeClass)e.Parameter;
}
else {
this.someObject = new SomeClass();
}
SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility = AppViewBackButtonVisibility.Visible;
SystemNavigationManager.GetForCurrentView().BackRequested += OnHardwareButtonsBackPressed;
base.OnNavigatedTo(e);
}
private void OnHardwareButtonsBackPressed(object sender, BackRequestedEventArgs e) {
// This is the missing line!
Frame.Navigate(typeof(FirstPage), this.someObject);
}
But when I press back button it goes back to the FirstPage OnNavigatedTo with no parameter, and then back to the SecondPage OnHardwareButtonsBackPressed and then back to FirstPage OnNavigatedTo with filled parameter.
Could you please advice me some better approach?
In your back handler, don't navigate forwards again, just call GoBack -- and it's typically easier if you handle that at a global level rather than at a page level.
You can store your application state (the things you want to persist across page navigations) in global / static objects, or you could directly modify the object that was passed from the initial navigation (if the calling page still has a reference, it will be able to see the changes).
I would consider doing a search for "MVVM Windows Apps" and looking at some of the results to learn about a common way of building XAML apps.
I am trying to build a custom button in newest BlackBerry 10 platform.
The button should change background image when it is clicked and then change it back when it is clicked the second time.
The button logic is fairly simple: once clicked, I check for the type of image currently in the button and change the image source.
I started with a basic QML custom control which looks like this (stripped of labels and other unimportant things):
import bb.cascades 1.0
Container
{
id: root
layout: DockLayout
{
}
function clickMe()
{
var source = myImage.defaultImageSource.toString();
console.log(source);
if (source.endsWith("image.png"))
{
myImage.defaultImageSource = "asset:///images/image_pushed.png";
}
else
{
myImage.defaultImageSource = "asset:///images/image.png";
}
}
ImageButton
{
id: myImage
defaultImageSource: "asset:///images/image.png"
}
onCreationCompleted:
{
myImage.clicked.connect(root.clickMe);
}
}
ImageButton click event is connected to JavaScript function clickMe. The function fires and the URL is logged to console correctly.
The problem is the IF clause, because the image_pushed.png is never set. Why is this the problem and how can I implement this button?
I am looking around for a only QML solution for this problem and I found this information:
the defaultImageSource property is of type QUrl, which does contain
toString() method.
toString() method returns QString, which indeed has function endsWith.
my QML reference: http://qt-project.org/doc/qt-4.8/qstring.html#endsWith
Thanks.
Within QML QString instances appear to be a normal JavaScript strings. This mapping is done automatically. And Javascript strings don't have a endsWith method. You can use the search method with an regular expression to achieve the same.
if (source.search(/image\.png$/ !== -1) { /* ... */ }
I think you can create more simple way by using property
for example:
Control{
id : myControl
property bool state
ImageButton{
defaultImageSource : state ? "firstImageAsset.png" : "secondImageAsset.png"
onClick :{
myControl.state = !myControl.state
}
}
}
I have already added 5 cammands in a form and I want to add a sixth but It does not display the sixth?
I am posting my codes below.
public Command getOk_Lastjourney() {
if (Ok_Lastjourney == null) {
// write pre-init user code here
Ok_Lastjourney = new Command("Last Journey", Command.OK, 0);
// write post-init user code here
}
return Ok_Lastjourney;
}
public Form getFrm_planjourney() {
if (frm_planjourney == null) {
// write pre-init user code here
frm_planjourney = new Form("Plan journey", new Item[] { getTxt_From(), getTxt_To(), getCg_usertype(), getCg_userpref(), getCg_searchalgo() });
frm_planjourney.addCommand(getExt_planjourney());
frm_planjourney.addCommand(getOk_planjourney());
frm_planjourney.addCommand(getOk_planFare());
frm_planjourney.addCommand(getOk_planDistance());
frm_planjourney.addCommand(getOk_planTime());
frm_planjourney.addCommand(getOk_planRoute());
frm_planjourney.setCommandListener(this);
// write post-init user code here
System.out.println("Appending.....");
System.out.println("Append completed...");
System.out.println(frm_planjourney.size());
frm_planjourney.setItemStateListener(this);
}
return frm_planjourney;
}
Given System.out.println I assume you were debugging with emulator, right? in that case it would be really helpful to provide a screen shot showing how exactly does not display the sixth looks like.
Most likely you just got too many commands to fit to area allocated so that some of them are not shown until scrolled. There is also a chance that sixth command was reassigned to some other soft-button and you didn't notice that. Or there's something else - hard to tell with details you provided.
A general note - handling six actions with commands might be not the best choice in MIDP UI. For stuff like that, consider using lcdui List API instead. IMPLICIT kind of lists allow for more reliable and user friendly design than commands.
Well, I'm developing a app in my cellphone that is going to connect to my PC, the problem is that everytime that I return a URLRequest to the cellphone, it shows the previous Form on the screen and not de actual one, for example this is what goes in my actionListener:
public void actionPerformed(ActionEvent ae) {
if (ae.getCommand() == guiaUtil.cSelecionar()) {
LoginRemote loginRemote = new LoginRemote();
try {
//This is the request, returns true or false, does not affect the form
loginRemote.login(tLogin.getText(), tPassword.getText());
} catch (Exception e) {
GuiaUtil.error(e);
return;
}
guiaUtil.mainApp().startMenu();
}
}
Then in the "guiaUtil.mainApp().startMenu()" I have this
public void startMenu() {
if (itemsMenu == null) {
itemsMenu = new List();
itemsMenu.setWidth(320);
itemsMenu.addItem("Sincronize Spots");
itemsMenu.addItem("Find Spots");
itemsMenu.addItem("Work");
itemsMenu.setFocus(true);
this.addComponent(itemsMenu);
this.addCommandListener(this);
this.addCommand(guiaUtil.cSelect());
Form form = new Form();
form.addComponent(itemsMenu);
}
form.show();
}
Anyway, after the request returns, it shows my Login form again, instead of showing the Menu List
Maybe what is going is that you are getting an exception, treating it with GuiaUtil.error and returning from actionPerformed without calling startMenu.
I would move guiaUtil.mainApp().startMenu() inside the try/catch block.
Not sure what happens in loginRemote.login(tLogin.getText(), tPassword.getText());
If you access the network, I would put that part in a different thread.
Inform the main thread by some kind of callback when the "remote login" is done,
you can show the menuForm from the edt then.
You have to put the following code outside the if condition.
Form form = new Form();
form.addComponent(itemsMenu);
You are having two form object. one inside if and another one outside of if. Object created inside the loop will loses the scope inside if. You are showing form object outside if. That's why, menu list screen was not displayed.