I'm currently trying to make a create account fragment and a choose profile pic fragment.
Fragment A/create account:
This houses Edittextfields for name, password, E-mail address.
There is also an Image view which represents the profile pic.
This Image view has a button on the side, which I want to use to switch over to Fragment B.
Fragment B/Choose Profile Pic:
Fragment is just an Image view and a couple of Image Buttons.
My Problem
Let's say the user has typed in all information on Fragment A and now wants to choose a profile pic, how do I save all the data temporary which is entered in Fragment A.
The second question is then, when the user clicks the Accept button on Fragment B, how do I sent the chosen Pic to Fragment A. So that I can switch over to Fragment A and restore the previously saved information and receive the drawable Image which the user has selected, to display it in the Image view.
Have a look at the new Android Architecture Components. Especially ViewModel.
https://developer.android.com/topic/libraries/architecture/viewmodel.html#sharing
There is a section on sharing data between fragments.
It's very common that two or more fragments in an activity need to
communicate with each other. Imagine a common case of master-detail
fragments, where you have a fragment in which the user selects an item
from a list and another fragment that displays the contents of the
selected item. This case is never trivial as both fragments need to
define some interface description, and the owner activity must bind
the two together. In addition, both fragments must handle the scenario
where the other fragment is not yet created or visible.
This common pain point can be addressed by using ViewModel objects.
These fragments can share a ViewModel using their activity scope to
handle this communication, as illustrated by the following sample
code:
public class SharedViewModel extends ViewModel {
private final MutableLiveData<Item> selected = new MutableLiveData<Item>();
public void select(Item item) {
selected.setValue(item);
}
public LiveData<Item> getSelected() {
return selected;
}
}
public class MasterFragment extends Fragment {
private SharedViewModel model;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
model = ViewModelProviders.of(getActivity()).get(SharedViewModel.class);
itemSelector.setOnClickListener(item -> {
model.select(item);
});
}
}
public class DetailFragment extends Fragment {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SharedViewModel model = ViewModelProviders.of(getActivity()).get(SharedViewModel.class);
model.getSelected().observe(this, { item ->
// Update the UI.
});
}
}
Making Activity as an intermediate can enable your fragment communication.
Refer Communicating with Other Fragments for "fragment-activity-fragment" communication. If you want to persist the data refer SharedPreference of android.
Why you want to create 2 Fragments ?
You can achieve same thing with different views. Let's say you can create one Linear/Relative(Layout Group) Layout with all the controls of 1st Fragment and create another layout(Layout Group) with 2nd Fragment controls. And then using animation show and hide layouts so you can have both the things in same fragment or activity and user won't even notice that thing.
This way you don't have to save data temporary and you will have to implement all the things in single file.
Related
I have a tab view with two fragments. Those two fragments contain a recycler view with cards.
Each card in both fragments had a button.
Clicking on fragment 1's button should open the fragment 2 as a separate page and vice-versa.
I am struggling to find a method to implement this without making every too complex and tightly coupled.
This is fragment one with its own Adapter.
And this is fragment two:
Clicking on that SELECT DONOR button in Donees page should open donor fragment in a new page where the user will be able to assign a donor for the selected donee.
So I have two needs here
1) To start a fragment from a fragment
2) To Keep track from which Donee the new donor page was opened so that I can assign a donor for that specific donee.
I hope this is understandable.
so far I have tried LocalBroadcast and FragmentManager but its hard to keep track of what I'm doing with the code.
Can you guys suggest a better technique to achieve this ?
the easiest solution would probably be, starting a new activity, passing something like an ID, name or something to the intent on an Button click.
Context.startActivity(new Intent(Context, YourAssigneeActivity.class)
.putExtra("ID",id));
So I assume that you do not switch to the other tab when you click a button on one tab. Therefore the fragment should fill the whole screen.
With this assumption in mind you most likely have to switch the Activity. This can be dones easily with an Intent:
Intent intent = new Intent(getActivity(), ActivityB.class)
intent.putExtra("KEY", <your required data to transfer>);
getActivity().startActivityForResult(intent);
Note that when you use putExtra() don't forget that you need to implement Parcelable in those objects (explained here)
To get to know which item was clicked you can use the following pattern (pseudocode - I personally think it's really clean):
FragmentA implements YourAdapter.callback {
onItemClicked(<YourObject> item) {
<starting new activity as described above>
}
}
class YourAdapter extends RecyclerView.Adapter {
Callback mCallback;
YourAdapter(Context context, otherStuff) {
mCallback = (Callback) context;
}
interface Callback {
onItemClicked(<YourObject> item)
}
YourViewHolder implements View.OnClickListener {
onClick(View v) {
mCallback.onItemClicked(<YourObject> item)
}
}
}
Once you are in your Activity, you can set the Fragment in onCreate() of your Activity. In the Activity retrieve the data with getIntent() in the onCreate before creating the Fragment. Then you can put your data in the Fragment with setArguments(<Bundle>). In the Fragment in the onCreateview() retrieve it with getArguments().
I know this is kind of conmplicated. A better solution would be to just switch to an Activity and forget about the Fragment. This would remove one layer of complexity.
If you directly go from Fragment to Fragment you can ignore the Activity part but the rest should stay the same.
Hope this was the answer you were looking for!
Edit: Note that mCallback = (Callback) context is null if the Activity is not implementing Callback
I've a "A" fragment as follows (recyclerview):
https://img.exs.lv/e/z/ezeliitis/frags.png
How should I effectively duplicate fragment "A" with different images/text (same layout) and make fragment "B"?
How should I implement Database information and storage? For instance, I'll have fragments "A" category - 'GAMES'. When I click it, it should transfer to duplicate fragment "B", where it has "Basketball", "Football" ect... Also. If I click the fragments picture, it should show a small square with short information. Should I just make 3 seperate tables? How to link Fragments A - Fragment B - Detail information?
Also, if I've categories in Fragment "A" as following: cars/food/girls and I click food, then it goes to Fragment "B" which holds pizza/drinks ect - how to make sure fragment B gives right information according to fragment A (make sure it doesnt give from fragment 'a' (food) a result of fragment 'b' which holds information about cars for instance, which would be wrong)?
You can use manual constructors for passing data from fragment A to fragment B.
public class fragB extends Fragment{
int type;
public fragB(){
this.type = DEFAULT_TYPE;
}
public fragB(int type){
this.type = type;
}
}
From fragment A do this to define your fragB
Fragment f = new fragB(TYPE_CAR);
or
Fragment f = new fragB(TYPE_FOOD);
Note: Empty constructor is just for resolving exception.
I have listview in one fragment that displays item from a sqlite database. When I click on one item it opens a menu to allow to open, add to another listview or delete. I want to be able to add it to another listview in another fragment on press. I tried adding it to another listview using bundles but I had no luck. I have a plan of creating another database table to store the added data and display it in a new listview. Would this work? or do any of you guys have another suggestion?
You can send data from one fragment to another. The best way to do this is by going through the parent activity. Something like this:
public class MyActivity extends FragmentActivity implements MyFragmentListener {
MyFragment1 frag1;
MyFragment2 frag2;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(0);
FragmentManager fm = getSupportFragmentManager();
frag1 = (MyFragment1) fm.findFragmentByTag("frag1");
frag1.setListener(this);
frag2 = (MyFragment2) fm.findFragmentByTag("frag2");
}
// Call this function from frag1 when you want to send the data to frag2
public void addToFrag2(ListItem item) {
frag2.addToList(item);
}
}
// Define whatever methods the fragments want to use to pass data back and forth
public interface MyFragmentListener {
void addToFrag2(ListItem item);
}
I've looked at various examples and dont quite understand exactly how this can be done.
I have 2 fragments each hosted by a seperate Activity and need to pass data between the two and update each other based on choices.
I have a clickable Textview in fragment1 that should open fragment2 and allow the user to select a choice from another list of TextViews each displaying a different option.
I want the choice of the user in fragment2 to update the text of the TextView in fragment1 based on the choice that was made.
I have a listener to start fragment 2 when the TextView is clicked:
v3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent i = new Intent(getActivity(), FragmentActivity2.class);
getActivity().startActivity(i);
}
});
When I click a TextView in fragment2 I would like the fragment to close, return to fragment1 and update the text
The easiest way to pass data between fragments is using listeners. You can implement one/two interface to exchange data (one for each activity). Your activity should implement an interface and then call the methdod in the inteface to update data:
public interface ChangeLinkListener {
public void onLinkChange(String link);
}
In the onclick method:
(ChangeLinkListener) getActivity()).onLinkChange(data.getLink());
Where onLinkChange is simply a method for example you could change the name as you prefer.
I've written a tutorial between passing data if you like you can look here
I am having trouble implementing a feature in my Android app.
Here's the setup:
ItemPagerActivity: An activity that contains a fragment that displays a pager.
ItemPagerFragment: The fragment containing a pager that loads other fragments. A cursor is used to load the fragments.
ItemFragment: The fragment in the pager, which performs an asynchronous task to load its data.
What I want is the following:
as a I swipe pages, the data in the currently displayed ItemFragment is communicated to the ItemPagerActivity (specifically, the name of the item will be used as the activity's title).
I've defined a listener in ItemFragment that notifies when the data is loaded:
public class ItemFragment ... {
public interface OnItemLoadedListener {
public void onItemLoaded(Item item);
}
private Collection<OnItemLoadListener> listeners;
private class LoadItemTask extends AsyncTask<...> {
...
public void onPostExecute(Item item) {
notifyItemLoaded(item);
...
}
}
}
If this fragment was wrapped by an Activity, then I could set the activity's title simply by doing the following:
public class ItemActivity {
public void onCreate(...) {
...
ItemFragment fragment = new ItemFragment();
fragment.registerItemLoadedListener(new ItemLoadedListener() {
public void onItemLoaded(Item item) {
setTitle("Item: " + item.getName());
}
});
...
}
}
So that's easy enough, and works as expected: when the activity starts, it creates the fragment, which loads the item, which notifies the activity, and the title is updated correctly.
But with ItemPagerFragment, the fragments are loaded pre-emptively: swiping to Fragment 3 may mean that Fragment 4 and Fragment 5 are created. Receiving notifications from the ItemFragment class when items are loaded is not correct here because the fragment displayed may not match the fragment that performed the last load.
Now the ViewPager class has a OnPageChangeListener which could be a solution: when I swipe, this listener is invoked with the current page number. From that page number, I need to (somehow) get the fragment representing that page from the adapter, get the Item data out of the fragment, and notify listeners that the Item is now loaded:
public class ItemPagerFragment ... {
private Collection<OnItemLoadedListener> listeners;
public View onCreateView(...) {
...
ViewPager pager = (ViewPager) view.findViewById(R.id.pager):
pager.setOnPageChangeListener(new OnPageChangeListener() {
public void onPageChange(int pageNumber) {
ItemFragment fragment = getItemFragment(pageNumber);
Item item = fragment.getLoadedItem();
notifyItemLoaded(item);
}
});
...
}
}
The ItemPagerActivity class would then register as a listener on the ItemPagerFragment class as follows:
class ItemPagerActivity ... {
public void onCreate(...) {
...
ItemPagerFragment fragment = new ItemPagerFragment();
fragment.registerOnItemLoadedListener(new OnItemLoadedListener() {
public void onItemLoaded(Item item) {
setTitle("Item: " + item.getName());
}
});
...
}
}
This looks good, but there are a number of problems:
The OnPageChangeListener may be invoked before a fragment has loaded its data (i.e., the fragment is swiped into view before the item has asynchronously loaded). So the call to fragment.getLoadedItem() may return null.
The OnPageChangeListener is not invoked for the initial page (only when a page changes, e.g. after a swipe action) so the activity title will be incorrect for the initial page.
The ViewPager class allows for only one OnPageChangeListener. This is a problem because I am also using the ViewPageIndicator library, which wants to assign a listener to the ViewPager.
I'm assuming that this pattern (notifying the activity of the data in a fragment that has been swiped into view) might be common, so I am wondering if there are any good solutions for this pattern, and to the three specific problems that I have identified above.
...so I am wondering if there are any good solutions for this pattern,
and to the three specific problems that I have identified above.
I don't know if I would call it a pattern but the OnPageChangeListener is the way to go.
The OnPageChangeListener may be invoked before a fragment has loaded
its data (i.e., the fragment is swiped into view before the item has
asynchronously loaded). So the call to fragment.getLoadedItem() may
return null.
First, your code should handle the "no data available situation" from the start. Your AsyncTasks will have the job of loading the data and also update the title only if the fragment for which they are working is the visible one(a position field in the ItemFragment tested against the ViewPager's getCurrentItem() method). The OnPageChangeListener will handle the update of the title after the data was loaded, as the user switches between pages and the data is available(it will return null if no data is available). To get the ItemFragment for a certain position you could use the code below:
ItemFragment itf = getSupportFragmentManager()
.findFragmentByTag(
"android:switcher:" + R.id.theIdOfTheViewPager + ":"
+ position);
if (itf != null) {
Item item = fragment.getLoadedItem();
notifyItemLoaded(item);
}
The OnPageChangeListener is not invoked for the initial page (only
when a page changes, e.g. after a swipe action) so the activity title
will be incorrect for the initial page.
See above.
The ViewPager class allows for only one OnPageChangeListener. This is
a problem because I am also using the ViewPageIndicator library, which
wants to assign a listener to the ViewPager
I admit I don't have much knowledge on the ViewPagerIndicator library but at a quick look on its site I saw:
(Optional) If you use an OnPageChangeListener with your view pager you
should set it in the indicator rather than on the pager directly.
titleIndicator.setOnPageChangeListener(mPageChangeListener);
I don't see where is the limitation.
For my purposes, it worked to use ViewPager.OnPageChangeListener.onPageSelected() in conjunction with Fragment.onActivityCreated() to perform an action when the Fragment is visible. Fragment.getUserVisibleHint() helps too.