I'm trying to follow the MVP (specifically Passive-View) pattern in a java swing ui application.
The basic design of the application reminds a wizard control. The screen is divided to two main parts:
an active view.
a static navigation bar, with navigation buttons.
The user can use buttons to change the active view, but the bar is always displayed.
Modeling this scenario, I have a bunch of diffirent screers, each with it's own presenter, view interface and view implementation (using JPanel). Then I have a Shell presenter, view intefrace and view implementation, using a JFrame. The idea is that the shell will load first and always by displayed, showing the bottom navigation bar and leaving a space for the active view. The shell presenter will allow setting the current active screen, somewhat like this:
interface View {
}
class Presenter {
View view;
public Presenter(View view) {
this.view = view;
}
public View getView() {
return view;
}
}
interface ShellView extends View {
void setActiveView(View activeView);
}
class ShellPresenter extends Presenter {
private ShellView shellView;
public void setActivePresenter(Presenter activePresenter) {
shellView.setActiveView(activePresenter.getView());
}
}
class ShellFrame implements ShellView {
private JFrame frame;
private JPanel activePanel;
private JPanel navigationBar;
public ShellFrame() {
Container c = frame.getContentPane();
c.add(activePanel);
c.add(navigationBar);
}
public setActiveView(View activeView) {
???
}
}
The problem is in the setActiveView method: I'm not sure how to set the activeView to the activePanel, when the View interface is general and as such doens't know anything about JPanels. Obviously I wouldn't want my presenters to know about JPanels as well.
Could you modify the definition of View to:
interface View {
JComponent getContainer();
}
So that each view can easily get the view contents? The shell needn't know what implementation of JComponent is being returned.
Your View interface needs to provide some way to obtain something displayable in a JPanel:
interface View {
Component getComponent();
}
Then in ShellFrame (assuming you use BorderLayout, as I would) you can set the view in the following way:
public setActiveView(View activeView) {
activePanel.add(activeView.getComponent(), BorderLayout.CENTER);
}
The problem is that your JFrame is the View, not each individual active sub-view. The view that is active right now is a rendering job, and therefore should be done by the View, not by the Presenter. Imagine you wanted to swap in a different View that instead of having only one subview visible, they were all visible, but the one that was active had a different background color. The presenter just controls which one is active, but the View controls what is meant by active.
So your task cannot be done without breaking encapsulation because you are trying to do a job that by it's very nature breaks encapsulation. So I would do something like this:
class PresenterManager {
private Presenter activePresenter;
private List<Presenter> allPresenters;
IView view;
PresenterManager(IView view) {
this.view = view;
view.subscribe(this);
}
void addPresenter(Presenter p) {
allPresenters.add(p);
}
void setView(int index) {
view.setView(index);
activePresenter = allPresenters.get(index);
}
}
class SwingView implements IView {
List<SubView> allViews;
SubView activeView;
int lastIndex;
public void setView(int index) {
if(index != lastIndex) {
activeView.setVisible(false);
activeView = allViews.get(index);
lastIndex = index;
}
}
}
Related
I'm using a Recycler View to show all the images from the galley or the external storage of a device in a Grid Layout Manager. And I'm using a Radio Button to show if the image is selected or not.
PROBLEM
Whenever I select or deselect a Radio Button from the visible Views in the Recycler View some other Views which are outside the Visible Screen got selected or deselected.
It is like I'm pressing on the same View of the Recycler View, but the images are different.
PROBLEM
well that's because of the recycler view concept of reusing the views instead of creating new views every time you scroll.
you see if you have 100 items you want to show in a recycler view and only 20 of them could appear to the user, recycler view creates only 20 view holder to represent the 20 items, whenever the user scroll recycler view will still have 20 view holder only but will just switch the data stored in this view holders rather than create new view holders.
now to handle selection of your items there's two ways to do this.
the naive way
hold selection in a boolean array inside the recycle view adapter.
whenever the user scrolls, the adapter calls onBindViewHolder to update the visible viewholder with the proper data.
so when onBindViewHolder gets called just set the radio button selection according the boolean array using the position sent in the method call
at the end of your usage to the recycler view you can create a getter method in the adapter to get the selection array list of boolean and pass the data based on it
public class PhotosGalleryAdapter extends RecyclerView.Adapter<PhotosGalleryViewHolder> {
ArrayList<Your_Data_ClassType> data;
ArrayList<Boolean> dataSelected ;
public PhotosGalleryAdapter(ArrayList<Your_Data_ClassType> data) {
this.data = data;
dataSelected = new ArrayList<>(data.size()) ;
}
...
#Override
public void onBindViewHolder(#NonNull PhotosGalleryViewHolder holder, int position) {
...
RadioButton radioButton = holder.getRadioButton()
radioButton.setChecked(dataSelected.get(position));
radioButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
dataSelected.set(holder.getAbsoluteAdapterPosition() , isChecked) ;
}
});
...
}
}
the other way is to use a selection tracker and it should be the correct way to handle selections in a recycler view.
the problem with this way is it needs a lot of editing to the code and creating new classes to include as parameters in the selection tracker, but in the end you'll find it worth the time you spent on it.
in order to start with this way you need to do the following :
firstly, decide what should be a key (String-Long-Parcelable) so the tracker should use to differentiate between your data , the safest way is either String or Parcelable as I once tried Long and ended up with lots and lots of problems (in your case I will assume it's the photo's uri which will be of type string)
secondly, you need to create two new classes, one that extends ItemDetailsLookup, and the other extends ItemKeyProvider, and should use the key as their generic type (the type that is put between <> )
your two classes should look like this (that you might copy them straight forward)
the one that extends ItemKeyProvider :
public class GalleryItemKeyProvider extends ItemKeyProvider<String>{
PhotosGalleryAdapter adapter ;
/**
* Creates a new provider with the given scope.
*
* #param scope Scope can't be changed at runtime.
*/
public GalleryItemKeyProvider(int scope,PhotosGalleryAdapter m_adapter) {
super(scope);
this.adapter = m_adapter;
}
#Nullable
#Override
public String getKey(int position) {
return adapter.getKey(position);
}
#Override
public int getPosition(#NonNull String key) {
return adapter.getPosition(key);
}
}
the one that extends ItemDetailsLookup :
public class GalleryDetailsLookup extends ItemDetailsLookup<String> {
private final RecyclerView recView ;
public GalleryDetailsLookup(RecyclerView m_recView){
this.recView = m_recView;
}
#Nullable
#Override
public ItemDetails<String> getItemDetails(#NonNull MotionEvent e) {
View view = recView.findChildViewUnder(e.getX(), e.getY());
if (view != null) {
RecyclerView.ViewHolder holder = recView.getChildViewHolder(view);
if (holder instanceof PhotosGalleryViewHolder) {
return ((PhotosGalleryViewHolder) holder).getItemDetails();
}
}
return null;
}
}
thirdly, you should include this new two methods in your adapter to be used by the above classes
public class PhotosGalleryAdapter extends RecyclerView.Adapter<PhotosGalleryViewHolder> {
...
public String getKey(int position) {
return data.get(position).getUri();
}
public int getPosition(String key) {
for (int i = 0; i < data.size(); i++) {
if (data.get(i).getUri() == key) return i;
}
return 0;
}
...
}
forthly (if there's an english word called forthly), you should initialize the tracker with all the above classes that were created before and he will handle the rest, the tracker takes as parameters
a unique selection tracker id (if that will be the only selection tracker you will use then name it anything)
the ItemKeyProvider that we created
the DetailsLookup that we created
a String-Long-Parcelable Storage to store the keys that were selected in (in our case it will be a String Storage)
a Selection predicate, it's responsible to handle the way of selection you want to do, you want it to be able to (select only one item-multiple selection with no limits- based on a weird algorithm like even only or odd only), in my case I will use a default multiple selection one but if you want to alter it with another selection algorithm you should create a new class that extends SelectionPredicates and implement your way of selection, you could also just check the other default ones might be what you're looking for.
anyway, that's how the initialization should look (you should put this code wherever you initialize your recycler view at whether it's in fragment or activity method):
private void initRecycleView() {
...
SelectionTracker<String> tracker = new SelectionTracker.Builder<>("PhotosGallerySelection",
Your_Recycler_View,
new GalleryItemKeyProvider(ItemKeyProvider.SCOPE_MAPPED, photosAdapter),
new GalleryDetailsLookup(Your_Recycler_View),
StorageStrategy.createStringStorage())
.withSelectionPredicate(SelectionPredicates.createSelectAnything())
.build();
...
}
I didn't find a way to let me initialize the adapter with data and then create the tracker inorder to make the viewholders know about their selection or not, so in this case I firstly created the tracker and then made the adapter know about it's data using a setter and notifyDataSetChanged
what I mean by that is after creating the tracker instantly set the tracker and data to the adapter, so the initRecycleView should look like this
private void initRecycleView() {
...
SelectionTracker<String> tracker = new SelectionTracker.Builder<>("PhotosGallerySelection",
Your_Recycler_View,
new GalleryItemKeyProvider(ItemKeyProvider.SCOPE_MAPPED, photosAdapter),
new GalleryDetailsLookup(Your_Recycler_View),
StorageStrategy.createStringStorage())
.withSelectionPredicate(SelectionPredicates.createSelectAnything())
.build();
photosAdapter.setTracker(tracker);
photosAdapter.setData(data);
photosAdapter.notifyDataSetChanged();
...
}
Last but no least, you should handle how the view holders should know if they were selected or not, so you should let the adapter know about the tracker and its data by creating a setter method in it, that's how the adapter should look like in the end :
public class PhotosGalleryAdapter extends RecyclerView.Adapter<PhotosGalleryViewHolder> {
ArrayList<Your_Data_Class> data;
private SelectionTracker<String> tracker;
public PhotosGalleryAdapter() {
data = new ArrayList<>();
}
public ArrayList<Your_Data_Class> getData() {
return data;
}
public void setData(ArrayList<Your_Data_Class> m_data) {
this.data = m_data;
}
#Override
public ScheduleViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
...
}
#Override
public void onBindViewHolder(#NonNull PhotosGalleryViewHolder holder, int position) {
...
boolean isSelected = tracker.isSelected(data.get(i).getUri());
RadioButton radioButton = holder.getRadioButton;
radioButton.setChecked(isSelected);
}
#Override
public int getItemCount() {
return data.size();
}
public String getKey(int position) {
return data.get(position).getUri();
}
public int getPosition(String key) {
for (int i = 0; i < data.size(); i++) {
if (data.get(i).getUri() == key) return i;
}
return 0;
}
public void setTracker(SelectionTracker<String> m_tracker) {
this.tracker = m_tracker;
}
}
(as you may notice if you initialized the adapter with its data through the constructor, when he asks the tracker if there were an item selected or not, it will result in a NullPointerException as at the moment of initializing the adapter you still didn't initialize the tracker)
that way you could keep track of your selection the way google suggests in their documentation (which I honestly don't know why the made it very complicate like that).
if you want to know all the selected item in the end of your application/fragment use, you should call tracker.getSelection() which will return a Selection List for you to iterate on
There's a tiny problem/feature with the tracker that it won't start selecting the first item until you use a long press on it, that happens only in the first item you select, if you do want this feature (start selecting mode by long press) then leave it as it is
incase you don't want it you can make the tracker select a ghost key (any unique string key that means nothing to your data) at the beginning which should later enable the selection mode with a simple click on any photo
tracker.select("");
this also the way to make a default/old selection at the beginning, you could make a for loop and call tracker.select(Key) if you do want the tracker to start with few items being selected
N.B : incase you use the Ghost Key method you should watchout that the selection array that will get returned when you call tracker.getSelection() will also contain this Ghost Key.
at the end if you do have the curiosity of reading about selection tracker in the documentation follow this link
or maybe if you know how to read kotlin follow this two links
implementing-selection-in-recyclerview
a guide to recyclerview selection
I was stuck in the selection problem for days before I figure how to do all that so I hope you find your way through it.
Omar Shawky has covered the solutions.
With my answer I will stress on the reason why someone may face this sort of an issues with recycler views and how to avoid this common issue in the future (avoiding pitfalls).
Reason:
This issue happens because RecyclerView recycles views. So a RecyclerView item's view once inflated can get reused to show another off screen (to be scrolled to) item. This helps reduces re-inflation of views which otherwise can be taxing.
So if the radio button of an item's view is selected, and the same view gets reused to show some other item, then that new item can also have a selected radio button.
Solution:
The simplest solution for such issues is to have an if else logic in your ViewHolder to provide logic for both selected and de-selected cases. We also do not rely on information from radio button itself for initial setup (we do not use radioButton.isSelected() at the time of setup)
e.g code to write inside your ViewHolder class:
private boolean isRadioButtonChecked = false; // ViewHolder class level variable. Default value is unchecked
// Now while binding in your ViewHolder class:
// Setup Radio button (assuming there is just one radio button for a recyclerView item).
// Handle both selected and de-selected cases like below (code can be simplified but elaborating for understanding):
if (isRadioButtonChecked) {
radioButton.setChecked(true);
} else {
radioButton.setChecked(false);
}
radioButton.setOnCheckedChangeListener(
(radioButton, isChecked) -> isRadioButtonChecked = isChecked);
Do not do any of the following while setting up:
private boolean isRadioButtonChecked = false; // class variable
//while binding do not only handle select case. We should handle both cases.
if (isRadioButtonChecked) { // --> Pitfall
radioButton.setChecked(true);
}
radioButton.setOnCheckedChangeListener((radioButton, isChecked) -> isRadioButtonChecked = isChecked);
OR
// During initial setup do not use radio button itself to get information.
if (radioButton.isChecked()) { // --> Pitfall
radioButton.setChecked();
}
For our application I had to implement a nested RecyclerView. I'm getting a list of Tables from JSON and every Table has another list with groups from each table. I can get everything on the screen as requested, the problem is the selection.
I have 2 different RecyclerViews on the screen and I can not seem to get a single selection working in this environment, especially after scrolling. Every group and every table has a Toggle Button, and only one can be active at a time.
This is how the main screen looks like
So far I've tried putting a boolean isSelected on the Model but that didn't work out at all. The closest solution I came up with was a helper class that searches every CompoundButton on-screen and deselects them all when one is selected. The problem is this helper class cant get the Buttons which are off-screen.
How I populate ParentAdapter (in MainActivity):
public void setAdapter(List<Table> tableList)
{
RecyclerView recycler_view_parent = findViewById(R.id.recyclerparent);
LinearLayoutManager manager=new LinearLayoutManager(MainActivity.this);
manager.setOrientation(LinearLayoutManager.HORIZONTAL);
recycler_view_parent.setLayoutManager(manager);
recycler_view_parent.setHasFixedSize(true);
recycler_view_parent.setItemViewCacheSize(tableList.size());
ParentAdapter parentAdapter=new ParentAdapter(tableList,MainActivity.this);
recycler_view_parent.setAdapter(parentAdapter);
}
How i populate ChildAdapter (in onBindViewHolder of ParentAdapter):
FlexboxLayoutManager manager = new FlexboxLayoutManager(context);
manager.setFlexDirection(FlexDirection.COLUMN);
manager.setJustifyContent(JustifyContent.FLEX_START);
manager.setFlexWrap(FlexWrap.WRAP);
manager.setAlignItems(AlignItems.BASELINE);
holder.recycler_view_child.setLayoutManager(manager);
holder.recycler_view_child.setHasFixedSize(true);
adapter = new ChildAdapter(tableList, tableList.get(position).getGroups(), context);
holder.recycler_view_child.setAdapter(adapter);
The desired output should be only 1 Table OR Group at a time can be toggled (in total, not one from every RecyclerView) and the state should be the same after scrolling/device rotation).
I did a lot of research over the last days on this subject and I can not seem to find a working example of nested RecyclerView with single selection over both RVs.
So does anyone have an idea on how to solve this? I think the biggest issue is telling the Parent that a Button in Child was toggled and vice-versa.
I think for the ParentAdapter it should look something like this:
#Override
public void onBindViewHolder(#NonNull RecyclerView.ViewHolder holder, final int position) {
final Table table = tablelist.get(position);
ViewHolder viewHolder = (ViewHolder) holder;
if (table.isTableSelected()) {
viewHolder.toggletable.setChecked(true);
lastToggled = position;
} else {
viewHolder.toggletable.setChecked(false);
}
viewHolder.toggletable.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
if (b) {
table.setTableSelected(true);
// notify ChildAdapter and group.setGroupSelected(false)
if (lastToggled >= 0) {
tablelist.get(lastToggled).setTableSelected(false);
// notify ChildAdapter and group.setGroupSelected(false)
notifyItemChanged(lastToggled);
}
lastToggled = position;
} else {
table.setTableSelected(false);
}
}
});
}
Thanks in advance.
UPDATE: Managed to come up with a solution myself, although 100% sure, not the best approach.
First of all, implement Greenrobots EventBus:
implementation 'org.greenrobot:eventbus:3.1.1'
Now in the Activity where you hold both RecyclerViews register the Event listener:
#Override
protected void onStart() {
super.onStart();
EventBus.getDefault().register(this);
}
and subscribe 2 methods. One for Parent Events and one for Children Events. This methods will trigger every time an item is selected!
#Subscribe(threadMode = ThreadMode.MAIN)
public void onParentEventClicked(ParentAdapter.ParentEvent event) {
// to access the inner adapter here you must set it to public in the ParentAdapter(public ChildAdapter adapter;)
adapter.adapter.deSelectChild();
}
#Subscribe(threadMode = ThreadMode.MAIN)
public void onChildEventClicked(ChildAdapter.ChildEvent event) {
// normal ParentAdapter reference(ParentAdapter adapter;)
adapter.deSelectParent();
}
Inside your ParentAdapter create a method to deselect all parent items and a static class to fire the event:
public void deSelectParent()
{
for (int i=0;i<data.size();i++)
{
data.get(i).setSelected(false);
}
notifyDataSetChanged();
}
public static class ParentEvent {
View view;
int position;
}
Inside your ChildAdapter create a method to deselect all child items and a static class to fire the event:
public void deSelectChild()
{
for (int i=0;i<data.size();i++)
{
datachild.get(i).setSelected(false);
}
notifyDataSetChanged();
}
public static class ChildEvent {
View view;
int position;
}
now in both Parent and Child onBindViewHolders, you need similar logic for your models:
if (item.isSelected()) {
holder.yourbutton.setChecked(true);
} else {
holder.yourbutton.setChecked(false);
}
holder.yourbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
ParentEvent event = new ParentEvent();
event.view = holder.yourbutton;
event.position = position;
EventBus.getDefault().post(event);
if (holder.yourbutton.isChecked()) {
for (int i = 0; i < data.size(); i++) {
data.get(i).setSelected(false);
}
data.get(position).setSelected(true);
} else {
data.get(position).setSelected(false);
}
notifyDataSetChanged();
}
});
And thats pretty much it, every click on a ParentItem will trigger the deselect method for ChildAdapter and vice-versa.
Due to the high usage of notifyDataSetChanged() I recommend using this line to get rid of the blinking:
recycler_view_parent.setItemAnimator(null);
Any problems let me know!
Apologies if this is poorly explained, I am having difficulty in understanding it myself. If you point out anything you don't understand I will do my best to correct any issues. Okay so here we go.
Several classes. (D&D sheet, sheet has weapons user can equip, this is about equipping said weapons which is stored in a list)
A fragment activity - CombatFragment
The arrayadapter list which is declared in CombatFragment -
AttackListViewContentAdapter
The realm object - Weapon
The realm object where a list of Weapon is held - Sheet
A number of XML files (The code of which I won't paste here as SO has a limit on code. content_combat, attack_list_item
What I've gathered so far is that when I create a new attackListViewContentAdapter it loops at a rapid and continued pace. So much so that the screen does not respond to me touching any of the widgets. I've done things like log a number each time it passes so it shows when it's doing it again and again. If you need information on that I can show you where I put the logs and what shows in my Logcat when I add an additional view (row).
I believe that it's something to do with the onChangedListener which keeps being triggered, even if I found the reason why how do I then get to a stage where I can create a new view and have the listener so it can record changes.
Please note in the interests of space I will be using abbreviated code. I've ignored things like dialog boxes and widgets which aren't relevant. So if it seems like something missing or you need to view the classes, it's possibly in the file which I've linked above each one.
CombatFragment
public class CombatFragment extends Fragment {
#BindView(R.id.lv_attack_spellcasting_content)
ListView lv_attack_spellcasting_title;
#Nullable
#Override
public View onCreateView(final LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.content_combat, container, false);
RealmList<Weapon> weaponList = sheet.getWeaponList();
final AttackListViewContentAdapter attackListViewContentAdapter = new AttackListViewContentAdapter(getActivity(), sheet, realm, weaponList);
weaponList.addChangeListener(new RealmChangeListener<RealmList<Weapon>>() {
#Override
public void onChange(RealmList<Weapon> weapons) {
/* Gives the adaptor a kick to know that the weapon realm list has changed */
attackListViewContentAdapter.notifyDataSetChanged();
loopOnChanged++;
}
});
lv_attack_spellcasting_title.setAdapter(attackListViewContentAdapter);
playerInit();
return rootView;
}
// This is a fake method, this is just to show that the .add is in it's own method which is triggered by a button press and not in onCreate
public void buttonPress() {
sheet.getWeaponList().add(realm.createObject(Weapon.class));
}
} `
AttackListViewContentAdapter
public class AttackListViewContentAdapter extends ArrayAdapter<Weapon> {
public AttackListViewContentAdapter(Context context, Sheet sheet, Realm realm, List<Weapon> weaponList) {
super(context, 0, weaponList);
this.sheet = sheet;
this.realm = realm;
}
#Override
#NonNull
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null)
//Because you're returning the view (AttachToRoot is false) the ArrayAdaptor (This class) will handle adding the view to the list.
convertView =
LayoutInflater.from(getContext()).inflate(R.layout.attack_list_item, parent, false);
return convertView;
}
}
Weapon
public class Weapon extends RealmObject {
#PrimaryKey
int weaponID;
//properties, set get methods etc.
}
Sheet
public class Sheet extends RealmObject {
#PrimaryKey
private int sheetID;
private RealmList<Weapon> weaponList;
public RealmList<Weapon> getWeaponList() {
return weaponList;
}
public void setWeaponList(RealmList<Weapon> weaponList) {
this.weaponList = weaponList;
}
}
content_combat
<ListView
android:id="#+id/lv_attack_spellcasting_content"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:columnCount="7"
android:rowCount="1" />
attack_list_item
Nothing really in there to include
Your problem is happening because of bad initialization of your spinner widgets within AttackListViewContentAdapter class.
You must set your spinners selection before setOnItemSelectedListener is set.
You must check whether your spinner selection is not equal to current selection, to avoid an infinite loop between onChange and onItemSelected methods. I mean, your spinners onItemSelected callbacks, execute a realm transanctions, then, those transanctions fire your onChange callback and finally, your onChange callback invokes notifyDataSetChanged() which make cycle start again going into an infinite loop.
To solve your problem, you should follow the next steps inside AttackListViewContentAdapter.java:
A) Remove the following lines from addWeaponToUI() method:
private void addWeaponToUI() {
et_name_value.setText(weapon.getWeaponName());
np_damage_number_of_die_value.setValue(weapon.getWeaponDamageNumberOfDie());
SheetEnum.Ability ability = SheetEnum.Ability.getEnumValue(weapon.getWeaponAbilityBonusInt());
tv_attack_bonus_value.setText(String.valueOf(sheet.getAbilityBonus(ability)));
// REMOVE below lines!
//s_damage_die_type_value.setSelection(weapon.getWeaponDamageDieTypeInt());
//s_damage_type_value.setSelection(weapon.getWeaponDamageTypeInt());
//s_ability_bonus_value.setSelection(weapon.getWeaponAbilityBonusInt());
}
B) Invoke spinner setSelection() before setOnItemSelectedListener(), then check selected item is not equal to selected position to avoid an infinite loop:
ArrayAdapter<CharSequence> damageDieTypeAdapter = ArrayAdapter.createFromResource(getContext(), R.array.die_type, android.R.layout.simple_spinner_dropdown_item);
s_damage_die_type_value.setAdapter(damageDieTypeAdapter);
//Set selection before listener
s_damage_die_type_value.setSelection(weapon.getWeaponDamageDieTypeInt());
s_damage_die_type_value.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View v, final int position, long id) {
//Check selected position is not equal to current position to avoid an infinite loop
if (position != weapon.getWeaponDamageDieTypeInt()) {
String[] value = getContext().getResources().getStringArray(R.array.die_type);
realm.executeTransaction(new Realm.Transaction() {
#Override
public void execute(Realm realm) {
weapon.setWeaponDamageDieType(position);
}
});
}
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
C) Repeat Step B for s_damage_type_value and s_ability_bonus_value spinners
For example, if I have:
EditText A;
TextView B;
ImageView C;
And I want to set all their visibilities to View.GONE, how can I do it in a way that instead of this:
A.setVisibility(View.GONE);
B.setVisibility(View.GONE);
C.setVisibility(View.GONE);
I do this:
groupD.setVisibility(View.GONE);
without having to put all of them in one RelativeLayout and then setting the RelativeLayout to View.GONE? Is there a Java class for this? Or do I have to get a library for it?
If not, can I do it manually so I can organize my project which has 30 views? I don't want to set each group to be in its own RelativeLayout because all views are dependent on each other.
With ButterKnife you can do:
#BindViews({ R.id.A, R.id.B, R.id.C })
List<View> views;
ButterKnife.apply(views, VISIBLE);
ButterKnife.apply(views, GONE);
//Action and Setter interfaces allow specifying simple behavior.
static final ButterKnife.Action<View> VISIBLE = new ButterKnife.Action<View>() {
#Override public void apply(View view, int index) {
view.setVisibility(View.VISIBLE);
}
};
static final ButterKnife.Action<View> GONE = new ButterKnife.Action<View>() {
#Override public void set(View view, int index) {
view.setVisibility(View.GONE);
}
};
Example adapted from the website
The best way will be passing the views to a single method. All of them are Views, so you can do something like this.
public void setViews(View view){
view.setVisibility(View.GONE);
}
And call the method like this:
setViews(editText);
Is there any way to change multiple TextView text sizes all at once? Also they may or may not be in single ViewGroup. I was hoping of doing by creating some kind of trigger/event that would act like pub/sub but got no ideas. Any Possibility?
You could just use a class which you register the TextViews with. Then have a method which goes through all the registered TextViews and sets the font size. Somethings like:
public class TextViewTextSizer {
private List<TextView> textViews;
public TextViewTextSizer() {
textViews = new ArrayList<>();
}
public void registerTextView(TextView textView) {
textViews.add(textView);
}
public void setTextSize(float size) {
for (TextView textView : textViews) {
textView.setTextSize(size);
}
}
}