Develop Reference

Getting a button to work in the list view

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

How to open a file the same name as defined in the String?

I'm creating a lyric app and I need some help in coding the next processes I need.
I created a ListView and added some Strings on it.
public class MainActivity extends AppCompatActivity {
String titles[] = new String [] {"Amazing Grace", "How Great Thou Art",
"King of All Kings", "What A Beautiful Name"};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView listView =(ListView) findViewById(R.id.titlelist);
ArrayAdapter<String> adapter=new ArrayAdapter<String>
(this,android.R.layout.simple_list_item_1,titles);
listView.setAdapter(adapter);
}
}
Now the next step is to create an OnItemClickListener and let's say
if "Amazing Grace" was selected from the list,
it will look for a file the same name as it is defined in the String.
For example : "Amazing Grace.xml" //even with the space included
so the logic will be like : open filelocation/"title that was selected".xml
I can't use "case" since I will be creating lots of song titles and add more as I update the app.
Thanks for reading, I'd really appreciate any help with this ;)

You should map Your lyrics, so when You click on item with pos = 5 You will know what item's ps correlates with what file(or xml).
Here is the sample how to map ids with filenames:
HashMap<String,Strin> lyricsMap = new HashMap<>();
lyricsMap(0, R.raw.song_lyric0);
lyricsMap(1, R.raw.song_lyric1);
lyricsMap(2, R.raw.song_lyric2);
lyricsMap(3, R.raw.song_lyric3);
lyricsMap(4, R.raw.song_lyric4);
lyricsMap(5, R.raw.song_lyric5);
lyricsMap(6, R.raw.song_lyric6);
//..
Here is the sample how to use OnItemClickListener:
AdapterView.OnItemClickListener onItemClickListener = new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int pos, long id) {
int rawResId = lyricsMap.get(pos);
//here comes the method for returning lyrics for file by it's resource id
//...
}
};
adapter.setOnItemClickListener(onItemClickListener);
P.S I assume You are not working on database items, otherwise You should use id instead of pos value.

To open file:
int selected = 0; // set selected to index of what is selected
File file = new File(Environment.getExternalStorageDirectory(), //folder location where you store the files
titles[selected]+".xml"); //in case of xml files. If other types, you'll need to add case for diff types
Uri path = Uri.fromFile(file);
Intent fileOpenintent = new Intent(Intent.ACTION_VIEW);
fileOpenintent .setDataAndType(path, "application/xml"); //for xml MIME types are text/xml and application/xml
try {
startActivity(fileOpenintent);
}
catch (ActivityNotFoundException e) {
}
Your biggest issue as you explained it was how to handle multiple file names. That's this part of code: titles[selected]+".xml"

How to pass object through activities by reference?

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();
}

send arraylist from one to another activity into listview android [duplicate]

This question already has an answer here:
Passing arraylist in intent from one activity to another
(1 answer)
Closed 7 years ago.
I am making an android app. It is simple and based on quotes. I have a database of around 300 quotes divided in 5 categories (movies, books, etc.) and I show them at random when a user clicks on a category, in a TextView. Now I want the users to have an option to save their favorite quotes, so I have another activity called Favorites where I want the favorites to show in a ListView.
For this I think that the best way is to have all the favorites the user will put in a String ArrayList, and then send the whole ArrayList to the Favorites activity where it will put the strings from the ArrayList in the ListView. But, every time I try to send an ArrayList to the other activity, my app crashes.
I only managed to send the current string that is shown on screen like this
text.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
intent.putExtra("key", text.getText());
Context context = getApplicationContext();
CharSequence text = "Added to favorites";
int duration = Toast.LENGTH_SHORT;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
And then I take it and put it in the other activity
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_favorites);
final ListView lista = (ListView) findViewById(R.id.listView);
Intent intent = getIntent();
tekst = intent.getStringExtra("key");
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, listItems);
lista.setAdapter(adapter);
listItems.add(tekst);
adapter.notifyDataSetChanged();
}
But then if I try to add another favorite, it just overwrites the previous one. So how should I deal with this? How to send all the favorites that the user wants to put? Is ArrayList the best option or is there another way?

Activity A :
ArrayList<String> list = new ArrayList<String>();
intent.putExtra("yourlist", list);
startActivity(intent);
Activity B:
ArrayList<String> list = getIntent().getSerializableExtra("yourlist");
I hope its help you..!

Your previous ArrayList is overwritten because every time you navigate to the Favorites activity, it gets recreated and so does the ArrayList. The data is not persisted. The best option would be to use a database and save the item to the database from one activity. Then the favorite items can be retrieved from the database inside the Favorites activity.

Android ListView: How to add a row with a buttonclick

I have a listview. In it, each row had a text saying 0:00. But now, I added a button on my actionbar but then I got stuck. I don't know how to make the button create a new row, displaying 0:00
This is my code for the data in a row.
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
RowData rowdata_data[] = new RowData[]
{
new RowData("0:00")
};
RowdataAdapter adapter = new RowdataAdapter(this,
R.layout.listview_item_row, rowdata_data);
listView1.setAdapter(adapter);
listView1 = (ListView)findViewById(R.id.listView1);
}
this is my RowData class:
public class RowData {
String title;
public RowData(String title) {
this.title = title;
}
}
So how should I implement a button click to add another row?
Under addtionbutton: should be the method.
public boolean onOptionsItemSelected(MenuItem item)
{
// Handle presses on the action bar items
switch (item.getItemId())
{
case R.id.additionbutton:
return true;
default:
return super.onOptionsItemSelected(item);
}
}

I don't know how to make the button create a new row
With your current solution it's not possible (in efficient way do it) because you're using static array of objects - it means array has fixed size (it means that you're assuming that size won't be changed at runtime).
But your goal is "slightly" different. You want after each click on Button increase number of objects by one. It means you don't know exactly how many rows you can have (or can be changed at runtime).
Due to things mentioned above you should (have to) use dynamic array with changeable size. For this reason you need to use as source of data List that is representation of dynamic array.
Basic algorithm:
Create new List with zero (or you can have by default one row at
start).
Then create public method in your adapter that will add new item to
collection and send request that Adapter should be refreshed (after you added new row into collection).
Assign OnClickListener to your Button and in onClick() method you'll use created method for adding new row into ListView.
Solution:
How to initialise ListAdapter:
// Activity-level variable scope
private List<RowData> items = new ArrayList<RowData>();
private RowdataAdapter adapter;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
listView1 = (ListView)findViewById(R.id.listView1);
// adding first item to List, it's optional step
items.add(new RowData("0:00"));
adapter = new RowdataAdapter(this, R.layout.listview_item_row, items);
listView1.setAdapter(adapter);
}
Method for adding new row into ListAdapter:
public void addRow(RowData newRow) {
// items represents List<RowData> in your Adapter class
this.items.add(newRow);
// sends request to update ListAdapter
notifyDataSetChanged();
}
How to update Adapter after click on Button:
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// add new row to Adapter
adapter.addRow(new RowData("0:00"));
}
});
Hope i helped you to solve your problem.

you need to create a dataset that you can change so you need to make your array a class wide variable so you can add to it when you need to
when you add the new row you need to notify the adapter that something changed so you do this
adapter.notifyDatasetChanged();
and that should update your list