My Main Page in my App is a TabbedPage
I have three Tabs:
Payment, Config, Maintain
One of the tabs is controlled by a setting to show it or not. When that is changed to false I remove the tab by doing the following:
tabPage.Children.Remove(ConfigTab);
This removal works fine. If I turn the tab back on I can Add the tab by using this code:
tabPage.Children.Add(ConfigTab);
But its added at the end of the list and the Navigation header is missing:
I looked at using the Insert method where I can sepcify an index
tabPage.Children.Insert(1,ConfigTab);
but this crashed the app with the following message:
Unhandled Exception: Java.Lang.IndexOutOfBoundsException: Invalid
index 2, size is 2
If I inspect the children at that point it has added the page at the correct index
Any suggestions on how I can dynamically insert a new page to a TabbedPage? And retain the navigation?
UPDATE:
I have now managed to get it working by doing the following :
var paymentPage = tabPage.Children.FirstOrDefault(p=> p.ClassId == "PaymentNavPage");
var configPage = GetConfigPage();
var maintenancePage = tabPage.Children.FirstOrDefault(p => p.ClassId == "MaintaintNavPage");
// Clear old Tabgs
tabPage.Children.Clear();
// Put pages back
tabPage.Children.Add(paymentPage);
tabPage.Children.Add(configPage);
tabPage.Children.Add(maintenancePage);
I'm still interested if there is a better way to use the Insert method and then to reset the Navigation Stack.
I'm experiencing the same thing with Insert to the Children. Your solution seems to be the only option to hide and show a page. I would suggest assigning the pages to variables so you don't have to loop through the Children every time you are hiding/showing ConfigPage. Based on the names I'm assuming that the pages are different from each other.
In the case of similar pages ItemsSource can be used with the help of DataTemplate. When binding the ItemsSource to ObservableCollection hiding and showing pages requires just to modify that collection. More info about that can be found here:
https://developer.xamarin.com/guides/xamarin-forms/application-fundamentals/navigation/tabbed-page/#Populating_a_TabbedPage_with_a_Template
The next code work for me:
tabPage.Children.Insert(1,ConfigTab);
Related
I'm new to all of this and was making good progress but I have hit a brick wall with working out how to do the next thing. I am using Kotlin and have a Fragment with an associated Recyclerview Adapter. I would like to set OnClick (On or Off) against items in a row depending upon a value in the Fragment which could change at any time.
My adapter works fine to show and update the array of data and also to implement OnClick.
I have tried sending a data element via a constructor which changed in the fragment but always showed as the initial setting in the adapter. The same with trying to call a method.
Many other questions touch on the issue but only show snippets of code, and it seems that I'm not advanced enough to get them working successfully in my code.
Could anyone please provide a pointer to a working set of Kotlin code that includes parsing a variable from fragment to adapter - perhaps in Git or a tutorial. I'm sure that if I can study a working program I can move forward. Thank you.
It would have been better if you had included your Adapter and Fragment code in the question, that would have helped us in understanding how you have setup everything and what data model are you passing to adapter.
But looking at your question, one solution that comes to my mind is to add an enabled boolean in your data model that is displayed in the ViewHolder. Using this you can set view.clickable = model.enabled. Now whenever your "value in the Fragment" changes you can update this list and let the adapter rebind items.
Note that the above solution is when you want to selectively enable/disable clicks on individual items. If you want to do this for all items at once, it's better to create a variable in adapter that you can change from the Fragment, and inside the clickListener you can check the value of that adapter variable. If it's false, just return out of the click listener. Something like,
view.setOnClickListener {
if(adapterValue) {
// handle Click
}
}
If this approach doesn't help, I would ask you to add more context in your question and show what you have done so far.
I have an enhanced loop, which will dynamically inflate however many layouts relevant to the number of values held in my array.
This works perfectly however, there is a method being called on each iteration, which also works but there is a big bug that I need help resolving.
Imagine there are 5 items in my array, therefore 5 layouts are inflated, in these layouts there is a little scratchcard type section on the layout.
Now if the user is on page 1, uses the scratchcard, then moves on to page 2, uses the scratchcard etc etc, it works fine.
But if the user is on page 1 and then goes to say, page 5 and then back to page 1 (basically in a random order), the scratchcard doesn't work.
From my understanding, the reason for this is that the method is being called an implemented on each iteration and the view is losing its state if the user scrolls back or scrolls in random orders.
Therefore I need a way to save the created view state in my viewpager.
Is this possible for my scenario? I have tried my best to find a solution, but cannot find something that feels relevant to my question.
Here is a snippet of the code in question. Thanks for any guidance or suggestions!
for (String x : array1) {
//loop out the number of layouts relative to the number of questions held in x
View current_layout = LayoutInflater.from(getActivity()).inflate(R.layout.question_fragment, null);
//use the pageAdapter to add the layout to the users view
pagerAdapter.addView(current_layout);
//call method to add functionality to the scratchcard
isCorrect(current_layout);
}
public void isCorrect(View current_layout) {
ScratchoffController controller1 = new ScratchoffController(getActivity())
.setThresholdPercent(0.40d)
.setTouchRadiusDip(getActivity(), 30)
.setFadeOnClear(true)
.setClearOnThresholdReached(true)
.setCompletionCallback(() -> {
})
.attach(current_layout.findViewById(R.id.scratch_view1), current_layout.findViewById(R.id.scratch_view_behind1));
ScratchoffController controller2 = new ScratchoffController(getActivity())
.setThresholdPercent(0.40d)
.setTouchRadiusDip(getActivity(), 30)
.setFadeOnClear(true)
.setClearOnThresholdReached(true)
.setCompletionCallback(() -> {
})
.attach(current_layout.findViewById(R.id.scratch_view2), current_layout.findViewById(R.id.scratch_view_behind2));
ScratchoffController controller3 = new ScratchoffController(getActivity())
.setThresholdPercent(0.40d)
.setTouchRadiusDip(getActivity(), 30)
.setFadeOnClear(true)
.setClearOnThresholdReached(true)
.setCompletionCallback(() -> {
})
.attach(current_layout.findViewById(R.id.scratch_view3), current_layout.findViewById(R.id.scratch_view_behind3));
ScratchoffController controller4 = new ScratchoffController(getActivity())
.setThresholdPercent(0.40d)
.setTouchRadiusDip(getActivity(), 30)
.setFadeOnClear(true)
.setClearOnThresholdReached(true)
.setCompletionCallback(() -> {
})
.attach(current_layout.findViewById(R.id.scratch_view4), current_layout.findViewById(R.id.scratch_view_behind4));
}
I ussually use ViewPager with Fragments and what you mention has happend to me when I try to keep references to the Fragment instances (in my case) outside of the viewpager.
This happens because the viewpager may create new instances of the Fragment it contains when you re-vist the tab in the way you mention. When this happens, the instance reference you hold outside of the viewpager is not anymore what the viewpager is showing.
In your case , according to this question, you have to oveeride instatiateItem and destroyItem. I think you can use these methods to save state restore state, and also you could update any external reference when instantiateItem is called.
I am trying to test my app which uses ViewPager. Each page contains fragments but these fragments are not always visible. I want to check visibility of a fragment in the currently visible page.
onView(withId(R.id.container_weather))
.check(matches(withEffectiveVisibility(ViewMatchers.Visibility.VISIBLE)));
But the problem is that espresso looks are all the pages not just the current page and I get the following error:
android.support.test.espresso.AmbiguousViewMatcherException: 'with id: eu.airpatrol.android:id/container_weather' matches multiple views in the hierarchy...
I had the same problem, however using the condition isCompletelyDisplayed() solved this problem as it only takes into account the on-screen views.
So, something like this should work:
onView(allOf(withId(R.id.container_weather), isCompletelyDisplayed()))
.check(matches(withEffectiveVisibility(ViewMatchers.Visibility.VISIBLE)));
Note: isDisplayed() works too in some cases but it also takes views off-screen into account and won't work if the ViewPager has any other page pr fragment loaded with the same view id.
Your tests are failing because of multiple elements with the same id. You can combine conditions using allOf(...). Then use isDisplayed() to check that matched view is visible on the screen. Below example can work:
onView(allOf(
withEffectiveVisibility(ViewMatchers.Visibility.VISIBLE),
withId(R.id.container_weather)))
.check(matches(isDisplayed()));
Ran into this exact same problem. I was fortunate because the view hierarchies in my ViewPager can be easily identified by their siblings, so I was able to solve this using the hasSibling matcher, like so:
onView(
allOf(
hasSibling(withId(R.id.some_sibling)),
withId(R.id.field_to_test)
)
).perform(replaceText("123"));
Not a perfect solution as it can be slightly brittle, but in my case I think it was an acceptable compromise.
I had similar problem, where I was reusing the button layout and it was giving me a matches multiple views in the hierarchy exception.
So the easy work around I did was to create 2 different screens and have 2 different methods with different text.
Withdraw Screen:
public WithdrawScreen clickWithdraw() {
onView(allOf(withId(R.id.save_button), withText("Withdraw")))
.perform(click());
return this;
}
Deposit Screen:
public DepositScreen clickDeposit() {
onView(allOf(withId(R.id.save_button), withText("Deposit")))
.perform(click());
return this;
}
and in my tests, I create a new instance of both screens and call the above methods based on screen reference which is a bit easy to test for.
WithdrawScreen withdrawInstance = new WithdrawScreen();
withdrawInstance.clickWithdraw();
DepositScreen depositInstance = new DepositScreen();
depositInstance.clickDeposit();
The point was they were using same id - R.id.save_button for button and I was replacing text of button based on visibility of the fragment we are on.
Hope it helps.
I have an activity that extends ListActivity, a list of "concepts" (let's call this list "C") and an onItemClickListener defined for this list. Whenever I click a "concept", no matter which one, the app must display another list. I have the following code to change the displayed list:
if(position == 0) change_list("adapter1");
else if (position == 1) change_list("adapter2");
else if (position == 2) change_list("adapter3");
else if (position == 3) change_list("adapter4");
else if (position == 4) change_list("adapter5");
Where position is the position of the clicked element in C
The function change_list performs setListAdapter(parameter) depending on the parameter I pass.
If I click the first element of C (the first concept), a list related to the first concept must appear. However, after calling setListAdapter(adapter), the data related to this concept is displayed, and also part of the C's list data.
For example: let's suppose C has these concepts:
A B C D E
and I click "A", which would lead to display a list with the following data: {a1,a2}
That's the final result:
a1 a2 C D E
And then, when I interact with another element on screen or I scroll down the list, the "ghost" data disappears and only the correct data remains on screen, just like this:
a1 a2
To make things worse, when I want to display list C again, nothing strange happens. Everything is displayed correctly.
At any time incorrect data is stored where it doesn't have to. One function my app must allow is to generate a txt file , and the generated txt file contains exactly the data I introduced. No data is corrupted or duplicated. I also tried using notifyDataSetChanged() and other functions, but I didn't solve the problem.
EDIT :
Here goes the xml code used for the main list of the activity:
<ListView
android:id="#android:id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#FF0000"
android:layout_below="#+id/afegir"/>
And an example of code in which I determine which contents must be displayed on screen:
else if(comprovar_concepte_actiu() == 1){
pnt = mydbhandler.getStoredValues("despeses1");
pnt.moveToFirst();
if(pnt.moveToFirst()){
do{
adapter_mostrar.add(pnt.getString(pnt.getColumnIndex("nom")));
}while(pnt.moveToNext());
}
adapter_mostrar.notifyDataSetChanged();
}
Where comprovar_concepte_actiu() returns and integer that tells which concept has been clicked in the main list C and adapter_mostrar is the single adapter I'm using now, instead of using multiple adapters (which made me use setListAdapter)
At the beginning of the activity, I call this.setListAdapter(adapter_mostrar). That's all I have.
EDIT 2 :
https://www.dropbox.com/s/7twgy043lkxb2x5/conceptes.java?dl=0
Here is a link to my conceptes.java activity. Press CTRL+F once opened and search "this is where I call.. " and you will directly get to the function where the change of list displayed on screen starts
I haven't found a solution yet. Any idea will be totally appreciated
The problem here is that - when you set a new adapter - the old data is still drawn. In other words, there has been no command to "refresh" the listView. However, the new adapter will be commanded to draw its own views. What ultimately occurs is that the old items are still there, the new items are redrawn, but when scrolled away the new adapter won't redraw/recreate the old items.
The solution is to simply refresh the adapter. However, there are two ways to go about this:
Add a new adapter every time and use myListView.invalidateViews(); or something similar [This is probably the easiest solution to implement, although probably not the best in the long run]
Change the dataset of the adapter and use notifyDataSetChanged() [on the adapter]
The latter option is a far better idea. You should use a single adapter and simply change its data over time. Once its dataset is changed, then tell the adapter that such a thing happened so it refreshes. However, you should read more here on all the different thoughts and processes about it, rather than take my opinion on it.
Edit:
There's apparently some very nicely, thought out answers around. Here's another one, that tells you more specifically about the differences between these two:
Is there any difference between ListView.invalidateViews() and Adapter.notifyDataSetChanged()?
Edit2:
With the onClickListener in mind, invalidateViews() will most likely not work, as it'll probably still draw the old views to "finish" the click (ie, draw the highlighting).
Changing the data directly inside a single adapter and using Adapter.notifyDataSetChanged() is your best bet, as it'll know to redraw everything from a single adapter and use only the current data defined by this single adapter.
Best to leave the data specifics (and defining what to draw based off of that data) up to what actually knows the data, rather than a higher up container that knows nothing specific about the actual data.
I've multiple choice (radio buttons) questions on pages. I'm getting user answers with hashmap. So I set previous question answer on start of next question. As a result I start using set hashmap on start 2.page.
BUT problem is: I think viewpager loads first 2 pages at the same time ; so "set hashmap" on start 2.page goes null ; because 1. page isnt loaded / or just loaded at the same time
How can I get rid of this problem ?
page: list answers (1)
page: get user choice(1), clear list(1), set list answers (2)
page: get user choice(2), clear list(2), set list answers (3) ...
maybe setoffscreenpagelimit 0 could be solution but lowest value is 1
This older answer can probably help you.
Basically you just want to know when another fragment is visible, and update it from there.