this is my first post here so be gentle :p
Here is the thing, I'm facing a really though issue and after several research i did not manage to figure out a clean solution. Let me explain:
I'm actually developing an android app for restaurant management.
In activity A, i'm able to create some articles with different parameters (picture, name, price ..).
I can also create a menu in which i indicate which articles are included. To do so i run Activity B that contains a dynamic list of the available articles (the ones i created) to be chosen. After picking up some of them the customised chosen objects are sent to Activity A through Parcel. And the chosen article list is updated in the menu.
But here is the thing, as far as i know, using Parcels create another instance of the object. As a result, if i modify or delete an article, the article list included in the menu does not change, and obviously i would like the list in the menu to be automatically updated.
Is there a way to simply pass customised objects through activities by reference?
What could be a clean solution to make the article list in the menu dynamic?
Here is some code:
In Activity A, in the menu interface i click + button to add an article, which run Activity B (the extras is the list of articles already included in the menu before, so in the beginning it's empty).
//Add article
FloatingActionButton addArticleButton = (FloatingActionButton)parentActivity.findViewById(R.id.addArticleButton);
addArticleButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
showMenuDetails(menuListView,menuAdapter,currentMenu);
parentActivity.startActivityForResult(new Intent(parentActivity.getApplicationContext(),ChooseArticleActivity.class).putParcelableArrayListExtra("menuArticleList",currentMenu.getArticles()),PICK_ARTICLES);
}
});
In activity B: I select Articles in a list of available Articles (the ones i created). After picking up i press OK button to put the list of chosen articles in result Intent as Parcelable Extras
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.choose_article_layout);
initializeLists();
this.resultIntent = new Intent();
}
private void initializeLists(){
final ListView articleToChoose = (ListView)findViewById(R.id.articleToChoose);
final ListView articleChosen = (ListView)findViewById(R.id.articleChosen);
final ArrayList<Article> articleToChooseList = (ArrayList<Article>)MainActivity.model.getArticleList().getArticleList().clone();
final ArrayList<Parcelable> articleChosenListParcelable = (ArrayList<Parcelable>)this.getIntent().getParcelableArrayListExtra("menuArticleList");
final ArticleAdapter articleToChooseAdapter = new ArticleAdapter(getApplicationContext(), articleToChooseList);
articleToChoose.setAdapter(articleToChooseAdapter);
ArrayList<Article> articleChosenListTemp = new ArrayList<>();
ArrayList<Article> articleToRemove = new ArrayList<>();
for(Parcelable a:articleChosenListParcelable){
articleChosenListTemp.add((Article)a);
for(Article article:articleToChooseList){
if(article.getName().equals(((Article) a).getName())){
articleToRemove.add(article);
}
}
}
articleToChooseList.removeAll(articleToRemove);
articleToChooseAdapter.notifyDataSetChanged();
final ArrayList<Article> articleChosenList = articleChosenListTemp;
final ArticleAdapter articleChosenAdapter = new ArticleAdapter(getApplicationContext(),articleChosenList);
articleChosen.setAdapter(articleChosenAdapter);
articleChosen.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Article articleClicked = articleChosenAdapter.getItem(position);
articleChosenList.remove(articleClicked);
articleToChooseList.add(articleClicked);
articleChosenAdapter.notifyDataSetChanged();
articleToChooseAdapter.notifyDataSetChanged();
}
});
articleToChoose.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Article articleClicked = articleToChooseAdapter.getItem(position);
if(!articleChosenList.contains(articleClicked)){
articleChosenList.add(articleClicked);
articleToChooseList.remove(articleClicked);
articleToChooseAdapter.notifyDataSetChanged();
articleChosenAdapter.notifyDataSetChanged();
}
}
});
Button okButton = (Button)findViewById(R.id.okButton);
okButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
chosenArticleListAttr = articleChosenList;
resultIntent.putParcelableArrayListExtra("articleList",chosenArticleListAttr);
setResult(RESULT_OK,resultIntent);
finish();
}
});
Button cancelButton = (Button)findViewById(R.id.cancelButton);
cancelButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
}
});
}
In activity A, in onActivityResult i catch the result and update the list, but the added Articles here are not the same instance as the article list in the model
if(requestCode==PICK_ARTICLES && resultCode==RESULT_OK){
ArticleAdapter articleAdapter = (ArticleAdapter) gestionMenusLayout.getMenuArticleListView().getAdapter();
ArrayList<Parcelable> chosenArticleList = (ArrayList<Parcelable>)data.getParcelableArrayListExtra("articleList");
gestionMenusLayout.getCurrentMenu().getArticles().clear();
for(Parcelable a:chosenArticleList){
gestionMenusLayout.getCurrentMenu().addArticle((Article)a);
}
articleAdapter.notifyDataSetChanged();
}
For debugging purpose only, I suggest that you use a public static List<Article> articleList and call it directly from whether activity A or B
A better but take-alittle-more-effort solution is that you store the list in a database, and every updates, queries, ... come through it.You can use the server's database (where people usually get articles from), or a offline database like Realm here
I figured it out with a quite easy and simple solution finally.
I keep passing my Article objects through intents by parcels.
But as it creates a new instance, instead of adding this instance i add the original one (the one from the model) after an equality key check (the name of the article). By doing so i keep the reference on my Article.
Thank you for helping!
Edit:
Here is the code:
if(requestCode==PICK_ARTICLES && resultCode==RESULT_OK){
ArticleAdapter articleAdapter = (ArticleAdapter) gestionMenusLayout.getMenuArticleListView().getAdapter();
ArrayList<Parcelable> chosenArticleList = (ArrayList<Parcelable>)data.getParcelableArrayListExtra("articleList");
gestionMenusLayout.getCurrentMenu().getArticles().clear();
ArrayList<Article> modelArticles = MainActivity.model.getArticleList().getArticleList();
for(Parcelable a:chosenArticleList){
for(Article modelArticle:modelArticles){
if(((Article)a).getName().equals(modelArticle.getName())){
gestionMenusLayout.getCurrentMenu().addArticle(modelArticle);
}
}
}
articleAdapter.notifyDataSetChanged();
}
Related
I have a Fragment inside the mainActivity, the fragment contains fragmentcontainerView which can be replaced by multiple child fragments with spinner onselectedListener. I want to able to pass those values from the child fragment via eg: Do something with: fragmentevent.TogetFName(); with a button in Mainactivity. In the parent fragment , I get the value from the child fragment(fragment_Birthday) with fragment_fr_event_birthday = (fragment_fr_event_Birthday) getChildFragmentManager().findFragmentById(R.id.fragment_event_child_fragment); and other value from other childfragment with frag_fr_event_wed = (fragment_fr_event_wedding) getChildFragmentManager().findFragmentById(R.id.fragment_event_child_fragment);, I know that they cannot be assigned with the different fragment class at once, but is there a clever way to do this or is there any other way I can pass value from child -> parent fragment->mainActivity
MainActivity:
public void onClick(View view){
case "Event":
Fragment_fr_Event fragment_fr_event = (Fragment_fr_Event) getSupportFragmentManager().findFragmentById(R.id.fragment_generated_mainView);
if(fragment_fr_event.TogetWedChildFcoupleName() !=null && fragment_fr_event.TogetEventType().equals("Wedding")){
testThis.setText(fragment_fr_event.TogetWedChildFcoupleName());
}if( fragment_fr_event.TogetEventType().equals("Birthday") && fragment_fr_event.TogetBirthdayFName() !=null){
testTat.setText(fragment_fr_event.TogetBirthdayFName());
}
}
ChildFragment(BirthdayFragment):
public String TogetEventBirthdayFName (){
EditText FBirthdayName = rootView.findViewById(R.id.Edittext_birthDay_FirstName);
return FBirthdayName.getText().toString();
}
ChildFragment(Wedding fragment):
public String toGetFcoupleName(){
EditText FCoupleName = rootView.findViewById(R.id.textView_wedding_Name);
return FCoupleName.getText().toString();
}
ParentFragment(EventFragment):
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
Spinner TypeEventSpinner = rootview.findViewById(R.id.type_event);
TypeEventSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
String tag_items = parent.getItemAtPosition(position).toString();
switch (tag_items){
case "Wedding":
frag_fr_event_wed = new fragment_fr_event_wedding();
FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_event_child_fragment, frag_fr_event_wed).disallowAddToBackStack().commit();
break;
case "Birthday":
fragment_fr_event_birthday = new fragment_fr_event_Birthday();
transaction = getChildFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_event_child_fragment , fragment_fr_event_birthday).disallowAddToBackStack().commit();
break;
}
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
}
public String TogetWedChildFcoupleName(){
if(frag_fr_event_wed !=null){
frag_fr_event_wed = (fragment_fr_event_wedding) getChildFragmentManager().findFragmentById(R.id.fragment_event_child_fragment);
return frag_fr_event_wed.toGetFcoupleName();
}return "Empty";
}
public String TogetBirthdayFName(){
if(fragment_fr_event_birthday != null){
fragment_fr_event_birthday = (fragment_fr_event_Birthday) getChildFragmentManager().findFragmentById(R.id.fragment_event_child_fragment);
return fragment_fr_event_birthday.TogetEventBirthdayFName();
}
return "Empty";
}
To be honest , I couldn't understand what you did there , but i got what you want , you want to communicate with parent's parent class , the way you are doing it made it so complicated even it's not readable , BUT of course there are always a good way to do something , in your case there are Android Navigation Component , which give you the simplicity and power to do make it much more easy to handle , You can put all your fragment in one graph and from within the destinations "fragment are called destinations here" you can communicate with other fragment and the parent using actions and global actions "going from one fragment to another is called action here" parameters, but there are no need to a parent's parent here , all destinations and its parent can share one ViewModel which will allow you to share data all around your app .
You can read more if it sound good to you here
I am new to android and my code has got a bit messy. I have successfully created a list view extended from item_layout.xml. When I click on the list view It works exactly how I want it. However in each item of the list view I have a button that when clicked I want the item of the list to delete.
When researching I have come across that you need to create a customer adapter to do this however I have come so far in the project that I wouldn't even know where to start.
This code it used successfully to when the list items are clicked it works. This is just put in the Main Activity class
mylist.setOnItemClickListener(
new AdapterView.OnItemClickListener(){
#Override
public void onItemClick(AdapterView<?> parent, View view, final int position, long id) {
}
}
);
I populate the list using this function just outside the main activity class. It is needed to be written like this as It gets the items from a database and has to be called depending on different circumstances
private void populatelistView() {
Cursor res = userDb.getAllRows();
String[] fromFeildnames = new String[]{ DatabaseUser.KEY_1, DatabaseUser.KEY_2};
int[] toViewIds = new int[]{R.id.textViewNum, R.id.textViewItem};
SimpleCursorAdapter myCursorAdaptor;
myCursorAdaptor = new SimpleCursorAdapter(getBaseContext(), R.layout.item_layout, res, fromFeildnames, toViewIds, 0);
//ListView mylist = (ListView) findViewById(R.id.listViewID);
mylist.setAdapter(myCursorAdaptor);
}
I would like to be able to get the button on each items to work by not changing much of what I have already written. I have tried just using the following code. But because it is in a different xml layout it display an error of null reference towards the item button
delete.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View v) {
View parentRow = (View) v.getParent();
ListView listView = (ListView) parentRow.getParent();
final int position = listView.getPositionForView(parentRow);
Toast.makeText(getApplicationContext(), "Button " + position, Toast.LENGTH_SHORT).show();
}
}
);
Please could someone help me make the button work without changing much code or give me a step by step tutorial on how to add an adapter but make my populateListView function do the same thing.
Ps. I have looked at so many tutorials about list adapters but can't find ones that are for my specific need
I am confused about calling the spinner widget through a custom function. I am create an app in which I use spinner 20-35 times a spinner widget in single layout or activity. So for this i want to avoid the spinner code repetition again and again. i am creating a method for this i add the items to the spinner but i want to pass item value on select to other activity which bind to that class
Here is my code
Spin_tester.class
public class Spin_tester {
public String result;
public Context ctx;
public Spin_tester(Spinner spinner, final ArrayList<String> arraylist, final Context ctx , final String value) {
this.ctx= ctx;
ArrayAdapter<String> adpts =
new ArrayAdapter<String>(ctx, android.R.layout.simple_dropdown_item_1line,arraylist);
spinner.setAdapter(adpts);
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
result = arraylist.get(position);
value = result ; // This is not working
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
}
}
Test_Activity.class
public class Test_Activity extends AppCompatActivity {
ArrayList<String> data_list = new ArrayList<>();
Spinner spins;
String value;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test);
spins = (Spinner)findViewById(R.id.spinner);
data_list.add("1");
data_list.add("2");
data_list.add("3");
data_list.add("4");
Spin_tester asd = new Spin_tester(spins,data_list,this,value);
TextView txt = (TextView)findViewById(R.id.textView17);
}
}
Please help
Thanks in advance
Java is a pass-by-value language, not pass-by-reference. What this means is that setting value in setOnItemSelectedListener will only change value within that method — the result won't be passed back anywhere.
I see that you've place the result in result. That is where the calling program will find the answer.
Remove all instances of value from Spin_tester and Test_Activity and then have your main activity get the result from asd.result
I'm going to get a little meta at this point: I've only answered the question you actually asked, but this code is wrong on so many levels that you're never going to get it to work. I strongly suggest you work your way through the examples and tutorials in the documentation before you try to proceed any further.
Ive searched for this all over the internet and there seems to be no simple explanation or tutorial on how to do this.
Basically, I want a layout that has a ListView where the user can click on an object and it will take them to the next layout.
In other words, using the listview as links to other layouts.
Everything Ive found on the internet has the end result of using a Toast... However I dont want a toast, i want to link to the next page.
Your question is slightly confusing so I'm going to make an assumption.
Is [LinearLayout1 LinearLayout2 Breadcrumb] suppose to be navigation or tabs that when selected insert their corresponding content into the Main Content?
If so I would suggest using fragments for each piece of content. Then when you click the navigation/tab, perform an animation of the fragment which slides the content in and out.
See the google docs for how to use fragments: http://developer.android.com/guide/components/fragments.html
See another stackoverflow answer for how to do the slide animation: Android Fragments and animation
or
http://android-developers.blogspot.com/2011/08/horizontal-view-swiping-with-viewpager.html
Here is some code that outlines how to invoke an activity following a click on a list row. Hopefully you can adapt the Toast example you mention to make this work for you.
The basic idea is that you launch a new Activity with a new Intent. You can pass any data you need from the listView row as an extra in the Intent.
final static String[] months = new String[] {"Jan","Feb","Mar"};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
R.layout.row_layout, R.id.text1, months);
setListAdapter(adapter);
}
#Override
protected void onListItemClick(ListView l, View v, int position, long id) {
int intItem = (int)id;
Intent intent= new Intent(this, SecondaryActivity.class);
intent.putExtra("MONTH", intItem);
startActivity(intent);
}
Why using ListView for it?
Each row must lead to different layout?
Its main benefits is in displaying dynamically changing data, but in your case data is constant, right?
Use vertical LinearLayout, fill it programmatically with "list elements", and add
leListComponent.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
startActivity(new Intent(YourActivity.this, TargetActivity.class));
}
});
to each.
If i didn't get it, and you feel good of using some adapter, it can be like this:
public class LeWrapper {
private String caption;
private Class<? extends Activity> target;
...POJO here...
}
v.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
//get leWrapper object from adapter
startActivity(new Intent(MenuActivity.this, leWrapper.getTarget()));
}
});
but its kinda overkill
Thanks for all the help guys. Sorry ive took my time replying. My solution is below :)
public class FP_WL1_ListView extends Activity {
private ListView lv1;
private String lv_arr[]={"Exercise Bike", "Treadmill", "Cross Trainer", "Squats", "Lunges"};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.fitnessprograms_wlday_one);
lv1=(ListView)findViewById(R.id.list);
lv1.setAdapter(new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1 , lv_arr));
lv1.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
final TextView mTextView = (TextView)view;
switch (position) {
case 0:
Intent newActivity0 = new Intent(FP_WL1_ListView.this,FitnessPrograms_Wlone_sp.class);
startActivity(newActivity0);
break;
case 1:
Intent newActivity1 = new Intent(FP_WL1_ListView.this,FitnessPrograms_Wlone_Treadmill.class);
startActivity(newActivity1);
break;
case 2:
Intent newActivity2 = new Intent(FP_WL1_ListView.this,FitnessPrograms_Wlone_Crosstrainer.class);
startActivity(newActivity2);
break;
case 3:
Intent newActivity3 = new Intent(FP_WL1_ListView.this,FitnessPrograms_Wlone_Squats.class);
startActivity(newActivity3);
break;
case 4:
Intent newActivity4 = new Intent(FP_WL1_ListView.this,FitnessPrograms_Wlone_Lunges.class);
startActivity(newActivity4);
break;
}
}
});
} }
OK, I've read around and see that Java only passes by value, not by reference so I don't know how to accomplish this.
I've 6 Spinners in an Android Activity that are populated with different SQLite queries.
The code to populate each Spinner and set the OnItemSelectedListener is very similiar so I was hoping to refactor to one method and call it 6 times with each Spinner ID and Sqlite query.
How do I get the Spinner onItemSelectedListener to change the right instance member on each different Spinner?
public void fillSpinner(String spinner_name, final String field_name) {
// This finds the Spinner ID passed into the method with spinner_name
// from the Resources file. e.g. spinner1
int resID = getResources().getIdentifier(spinner_name, "id",
getPackageName());
Spinner s = (Spinner) findViewById(resID);
final Cursor cMonth;
// This gets the data to populate the spinner, e.g. if field_name was
// strength = SELECT _id, strength FROM cigars GROUP BY strength
cMonth = dbHelper.fetchSpinnerFilters(field_name);
startManagingCursor(cMonth);
String[] from = new String[] { field_name };
int[] to = new int[] { android.R.id.text1 };
SimpleCursorAdapter months = new SimpleCursorAdapter(this,
android.R.layout.simple_spinner_item, cMonth, from, to);
months.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
s.setAdapter(months);
// This is setting the Spinner Item Selected Listener Callback, where
// all the problems happen
s.setOnItemSelectedListener(new OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> parent, View view,
int position, long id) {
Cursor theCursor = (Cursor) parent.getSelectedItem();
// This is the problem area.
object_reference_to_clas_member_of_field_name = theCursor
.getString(theCursor.getColumnIndex(field_name));
}
public void onNothingSelected(AdapterView<?> parent) {
// showToast("Spinner1: unselected");
}
});
}
You call this method like this fillSpinner("spinner1","strength");.
It finds the spinner with id spinner1 and queries the database for the strength field. field_name, which is strength in this example had to be declared a final variable to be used in the onItemSelectedListener or I'd get the error Cannot refer to a non-final variable field_name inside an inner class defined in a different method.
But how do I get the onItemSelectedListener to change the value of a different instance member when each different Spinner is used? This is the all important line of code:
object_reference_to_clas_member_of_field_name = theCursor .getString(theCursor.getColumnIndex(field_name));
I can't use a final String as the variable will obviously change when the user selects a different value. I've read around a good bit and am stumped to a solution. I can just copy and paste this code 6 times and forget about refactoring but I'd really like to know the elegant solution. Post a comment if you don't understand my question, I'm not sure if I explaned myself well.
You can do it, by passing additional class as parameter of fillSpinner method:
A. Create interface
public interface OnSpinnerValueSelected {
void onValueSelected(String selectedValue);
}
B. Change your method a bit:
public void fillSpinner(String spinner_name, final String field_name,
final OnSpinnerValueSelected valueChangeListener) {
// Prepare spinner
s.setOnItemSelectedListener(new OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> parent, View view,
int position, long id) {
Cursor theCursor = (Cursor) parent.getSelectedItem();
valueChangeListener.onValueSelected(theCursor
.getString(theCursor.getColumnIndex(field_name)));
}
public void onNothingSelected(AdapterView<?> parent) {
}
});
}
C. provide listener:
fillSpinner("spinner1","strength", new OnSpinnerValueSelected() {
public void onValueSelected(String selectedValue) {
yourObject.setField(selectedValue);
}
});
Refactor your listener to a new "class". Initialize with the right arguments/instances as required so that the repeated "code" is reusuable.
Right, this is how I managed it but I'm still open to new suggestions for an accepted answer and I also created a bounty.
I didn't create a new class like panzerschreck suggested so I'm posting this as a new answer to my own question. Bit of a hack but I just created an if..then..else statement in the listener to check what spinner was selected and then set a different instance member.
s.setOnItemSelectedListener(new OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> parent, View view,
int position, long id) {
Cursor theCursor = (Cursor) parent.getSelectedItem();
if (field_name.equalsIgnoreCase("strength")) {
strength=theCursor.getString(theCursor.getColumnIndex(field_name));
} else if (field_name.equalsIgnoreCase("ring")) {
ring_gauge=theCursor.getString(theCursor.getColumnIndex(field_name));
} else if (field_name.equalsIgnoreCase("country")) {
country=theCursor.getString(theCursor.getColumnIndex(field_name));
} else if (field_name.equalsIgnoreCase("wrapper")) {
wrapper=theCursor.getString(theCursor.getColumnIndex(field_name));
} else if (field_name.equalsIgnoreCase("length")) {
length=theCursor.getString(theCursor.getColumnIndex(field_name));
} else if (field_name.equalsIgnoreCase("price")) {
price=theCursor.getString(theCursor.getColumnIndex(field_name));
}
// showToast(category);
}
public void onNothingSelected(AdapterView<?> parent) {
// showToast("Spinner2: unselected");
}
});
Here are the class members
private String strength,ring_gauge,country,wrapper,length,price;
Bit of hack but without Java allowing objects to be really passed by reference, it's all I could do.