I was wondering if somebody could further explain how to implement a delete button inside a listview that is populated from an SQLite database. I've read the responses to the following question that is essentially what I'm asking as well, but I don't understand it:
How can I implement a delete button in a ListView and delete from database?
In my custom row .xml file, I included a delete button that implements the method delete() onClick. It also includes an alert dialog, by the way. Here's the code that I have so far for my delete() method; whenever I try to use it, it never gets the right activtiy entry.
public void delete(View view){
final int position = listview.getPositionForView((View) view.getParent());
String id = cursor.getString(cursor.getColumnIndex(SQLiteAdapter.KEY_ID));
AlertDialog.Builder myDialog = new AlertDialog.Builder(MainActivity.this);
myDialog.setTitle("Delete activity entry \"" + id + "\"?");
myDialog.setPositiveButton("DELETE", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface arg0, int arg1) {
mySQLiteAdapter.delete(position);
cursor.requery();
}
});
myDialog.setNegativeButton("CANCEL", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface arg0, int arg1) {
}
});
myDialog.show();
}
A solution is to implement a custom ArrayAdapter.
public class MyArrayAdapter extends ArrayAdapter<YourObject>
{
private ArrayList<YourObject> items;
public LiftArrayAdapter(Context context, int textViewResourceId, ArrayList<YourObject> items)
{
super(context, textViewResourceId, items);
this.items = items;
}
#Override
public View getView(int position, View convertView, ViewGroup parent)
{
View v = convertView;
if (v == null)
{
LayoutInflater vi = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.your_view_xml, null);
}
final YourObject obj = items.get(position);
TextView lblLift = (TextView) v.findViewById(R.id.lbl_lift);
ImageButton btnDelete = (ImageButton) v.findViewById(R.id.btn_delete);
btnDelete .setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
//TODO delete 'obj' from database
}
});
return v;
}
}
Then, to bind a list of objects to your listview:
List<YourObject> list = ...
MyArrayAdapter myArrayAdapter = new MyArrayAdapter (.., .. , list);
listView.setAdapter(myArrayAdapter);
Related
I have a list which can be updated by user but there was an error on notifyDataSetChanged() I'm doing a to-do list, when I added notifyDataSetChanged() in array adapter it shows an error said that
error: notifyDataSetChanged() in ArrayAdapter is defined in an inaccessible class or interface
Cannot access 'notifyDataSetChanged()' in 'android.widget.ArrayAdapter'
Error happened on note_editor.
Following is my code:
note_editor (another activity)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_note_editor);
EditText editText = (EditText) findViewById(R.id.editText);
Intent intent = getIntent();
noteId = intent.getIntExtra("noteId", -1);
// note id variable transferred from main activity
if (noteId != -1) {
editText.setText(MainActivity.notes.get(noteId));
} else {
MainActivity.notes.add("");
noteId = MainActivity.notes.size() - 1;
MainActivity.arrayAdapter.notifyDataSetChanged(); //error happened here
}
MainActivity
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CheckBox checkBox = (CheckBox) findViewById(R.id.checkBox);
ListView listView = (ListView) findViewById(R.id.listView);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
SharedPreferences sharedPreferences =
getApplicationContext().getSharedPreferences
("com.example.application1", Context.MODE_PRIVATE);
HashSet<String> set = (HashSet<String>)
sharedPreferences.getStringSet("notes", null);
if (set == null) {
notes.add("Example note");
} else {
notes = new ArrayList(set);
}
arrayAdapter = new CustomAdapter
(this, R.layout.simplerow, notes);
listView.setAdapter(arrayAdapter);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new
Intent(getApplicationContext(),note_editor.class);
startActivity(intent);
}
});
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick
(AdapterView<?> adapterView, View view, int i, long l) {
Intent intent = new Intent(getApplicationContext(),
note_editor.class);
intent.putExtra("noteId", i);
startActivity(intent);
}
});
listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
public boolean onItemLongClick
(AdapterView<?> adapterView, View view, int i, long l) {
final int itemToDelete = i;
new AlertDialog.Builder(MainActivity.this)
.setIcon(android.R.drawable.ic_dialog_alert)
.setTitle("Are you sure?")
.setMessage("Do you want to delete this note?")
.setPositiveButton("Yes",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialogInterface, int i) {
notes.remove(itemToDelete);
arrayAdapter.notifyDataSetChanged();
SharedPreferences sharedPreferences =
getApplicationContext().getSharedPreferences("com.example.application1",Context.MODE_PRIVATE);
HashSet<String> set = new HashSet(MainActivity.notes);
sharedPreferences.edit().putStringSet("notes", set).apply();
}
}
)
.setNegativeButton("No", null)
.show();
return true;
}
});
}
CustomAdapter
private class CustomAdapter extends ArrayAdapter<String> {
Context context;
ArrayList<String> notes = new ArrayList<>();
int layoutResourceId;
public CustomAdapter(Context context, int layoutResourceId,
ArrayList<String> objects) {
super(context, layoutResourceId, objects);
this.layoutResourceId = layoutResourceId;
this.notes=objects;
this.context=context;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
CheckBox chBox = null;
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.simplerow,
parent, false);
chBox = (CheckBox) convertView.findViewById(R.id.checkBox);
convertView.setTag(chBox);
chBox.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
TextView tv = findViewById(R.id.rowTextView);
tv.setPaintFlags(tv.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
arrayAdapter.notifyDataSetChanged();
}
});
}
return convertView;
}
}
Any ideas what is wrong here?
Need to change only one line. Just change arrayAdapter.notifyDataSetChanged() as below.
#Override
public void onClick(View v) {
TextView tv = findViewById(R.id.rowTextView);
tv.setPaintFlags(tv.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
notifyDataSetChanged();
}
});
}
return convertView;
}
}
Error showing that the adapter object is not accessible.
You are actualy trying to update an activity already destroyed. Notify adapter from MainActivity itself.
It seems to me that the error happens because you defined your CustomAdapter as a private class, and for that reason you cannot access its methods outside of it.
The CustomAdapter should be defined as public (or package access if everything is located on the same package).
That being said, I agree with other comments pointing out that that's not the proper way to call notifyDataSetChanged (if you still have doubts about it, I suggest opening a different question for that).
PrintScreen
I have a listView with 3 Views
1) ImageView
2) TextView
3) Button
What I want to make is that when I click on a button, it gets triggered and call to the specific person.
Telephone numbers are stored in strings.xml file as
<string-array name="telePhoneNummber">
<item>123</item>
<item>8765</item>
<item>565767</item>
</string-array>
And here is my Adapter Class.
public class MoviesAdapter extends ArrayAdapter {
List list = new ArrayList();
public MoviesAdapter(Context context, int resource) {
super(context, resource);
}
static class DataHandler {
ImageView Poster;
TextView title;
Button telePhone;
}
#Override
public void add(Object object) {
super.add(object);
list.add(object);
}
#Override
public int getCount() {
return this.list.size();
}
#Override
public Object getItem(int position) {
return this.list.get(position);
}
#Override
public View getView(int position, View convertView, final ViewGroup parent) {
View row;
row = convertView;
DataHandler handler;
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = inflater.inflate(R.layout.row_layout, parent, false);
handler = new DataHandler();
handler.Poster = (ImageView) row.findViewById(R.id.movie_poster);
handler.title = (TextView) row.findViewById(R.id.movie_title);
handler.telePhone = (Button) row.findViewById(R.id.btn_call);
row.setTag(handler);
} else {
handler = (DataHandler) row.getTag();
}
MovieDataProvider dataProvider;
dataProvider = (MovieDataProvider) this.getItem(position);
handler.Poster.setImageResource(dataProvider.getMovie_poster_resource());
handler.title.setText(dataProvider.getMovie_title());
handler.telePhone.setText(dataProvider.getTelePhone());
return row;
}
}
Don't pay attention on the naming convention please.
In your getView() method, simply add an onClickListener() to the appropriate button resource...
handler.telePhone.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Intent to launch phone dialer
Intent intent = new Intent(Intent.ACTION_DIAL);
intent.setData(Uri.parse("tel:" + dataProvider.getTelePhone().trim()));
context.startActivity(intent);
}
});
EDIT 1: not sure whether the NullPointerException in your onClickListener occurs on line 82 or 83 of your adapter class but you probably need to pass context to it. Add the following to your current code:
Below List list = new ArrayList(); add Context context;
Change your constructor to:
public MoviesAdapter(Context context, int resource) {
super(context, resource);
this.context = context;
}
And see if it solves the problem.
EDIT 2: Or, leave your original code untouched and in the onClickListener, change context.startActivity(intent); to initActivity(intent); for which you'll need to add the following method:
private void initActivity(Intent intent) {
this.getContext().startActivity(intent);
}
Write your Listview on click listener and open the phone Dialer like this:
listView.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
String[] numberArray= context.getResources().getStringArray(R.array.telePhoneNummber); // get array from strings.xml
// launch dialer with pre-filled phone number
Intent phoneDialerIntent= new Intent(Intent.ACTION_DIAL);
phoneDialerIntent.setData(Uri.parse("tel:" + numberArray[position]));
startActivity(phoneDialerIntent);
}
});
Please tell me how to add items in listview arrayadapter?
I found only how to make for standard adapter
Activity:
public class Activity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.m);
ListView lv=(ListView) findViewById(R.id.lv);
String[] Id1={"1","2","3"}, Text1={"one","two","three"};
CustomAdapter ad = new CustomAdapter(this, Id1 , Text1);
ad.setCustomListener(new LVListener() {
public void onClick(String text) {
Log.d("APP", text);
}
});
lv.setAdapter(ad);
Button btn = (Button) findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
btn.setVisibility(View.GONE);
String[] Id2={"4","5","6"},Text2={"four","five","six"};
// add Id2 and Text2 in listview
}
});
}
}
CustomAdapter:
public class CustomAdapter extends ArrayAdapter<String> {
private final Context context;
private final String[] id, text;
private ListViewListener micl;
public CustomAdapter(Context context, String[] id, String[] text) {
super(context, R.layout.list, id);
this.context = context;
this.id = id;
this.text = text;
}
public void setCustomListener(ListViewListener micl) { this.micl = micl; }
#Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View View = inflater.inflate(R.layout.list, parent, false);
final int pos = position;
final TextView tView = (TextView) View.findViewById(R.id.textView);
tView.setText(text[pos]);
rowView.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (micl != null)
micl.onClick(text[pos]);
}
});
return View;
}
}
I tried to do with notifyDatasetChanged() but nothing happened.
Please tell me how to do that.
ArrayAdapter has the add method, but in order to use it the dataset you provide to the super can not be an array, that's because the using Arrays.asList(objects), that returns an immutable list. From the documentation
Returns a List of the objects in the specified array. The size of the
List cannot be modified, i.e. adding and removing are unsupported, but
the elements can be set. Setting an element modifies the underlying
array.
This is my MainActivity.java
public class MainActivity extends Activity implements OnClickListener{
ArrayList<Product> products = new ArrayList<Product>();
final Context context = this;
ListAdapter boxAdapter;
String[] dataArray;
EditText editText;
//name that get back through the dialog
private String getName;
private String selectedItem;
private ArrayAdapter<String> adapter; // The list adapter
/** Called when the activity is first created. */
public void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.listview);
fillData();
boxAdapter = new ListAdapter(this, products);
ListView lvMain = (ListView) findViewById(R.id.lvMain);
lvMain.setAdapter(boxAdapter);
Button btn = (Button) findViewById(R.id.AddItem);
//the add item button function
btn.setOnClickListener(new OnClickListener(){
public void onClick(View arg0) {
//get the dialog view
LayoutInflater li = LayoutInflater.from(context);
View promptsView = li.inflate(R.layout.dialog, null);
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(
context);
// set prompts.xml to alertdialog builder
alertDialogBuilder.setView(promptsView);
final EditText userInput = (EditText) promptsView
.findViewById(R.id.insert);
// set dialog message
alertDialogBuilder
.setCancelable(false)
.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int id) {
// get user input and set it to result
// edit text
getName=userInput.getText().toString();
products.add(new Product(getName,false));
}
})
.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int id) {
dialog.cancel();
}
});
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
}
});
// Create the listener for normal item clicks
OnItemClickListener itemListener = new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View v, int position, long rowid) {
Toast.makeText(
getApplicationContext(),
"You have clicked on " + parent.getItemAtPosition(position).toString() + ".",
Toast.LENGTH_SHORT).show();
}
};
//the long press to delete function
OnItemLongClickListener itemLongListener = new OnItemLongClickListener()
{
#Override
public boolean onItemLongClick(AdapterView<?> parent, View view,
int position, long id) {
// Store selected item in global variable
selectedItem = parent.getItemAtPosition(position).toString();
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setMessage("Do you want to remove " + selectedItem + "?");
builder.setCancelable(false);
builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
products.remove(selectedItem);
boxAdapter.notifyDataSetChanged();
Toast.makeText(
getApplicationContext(),
selectedItem + " has been removed.",
Toast.LENGTH_SHORT).show();
}
});
builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// Create and show the dialog
builder.show();
// Signal OK to avoid further processing of the long click
return true;
}
};
lvMain.setOnItemClickListener(itemListener);
lvMain.setOnItemLongClickListener(itemLongListener);
}
void fillData() {
dataArray = getResources().getStringArray(R.array.ChecklistData);
for(String productName : dataArray)
{
products.add(new Product(productName,false));
}
}
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
}
}
This is ListAdapter.java
public class ListAdapter extends BaseAdapter {
Context ctx;
LayoutInflater lInflater;
ArrayList<Product> objects;
ListAdapter(Context context, ArrayList<Product> products) {
ctx = context;
objects = products;
lInflater = (LayoutInflater) ctx
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
#Override
public int getCount() {
return objects.size();
}
#Override
public Object getItem(int position) {
return objects.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if (view == null) {
view = lInflater.inflate(R.layout.item, parent, false);
}
Product p = getProduct(position);
((TextView) view.findViewById(R.id.tvDescr)).setText(p.name);
/*((TextView) view.findViewById(R.id.tvPrice)).setText(p.price + "");
((ImageView) view.findViewById(R.id.ivImage)).setImageResource(p.image);*/
CheckBox cbBuy = (CheckBox) view.findViewById(R.id.cbBox);
cbBuy.setOnCheckedChangeListener(myCheckChangList);
cbBuy.setTag(position);
cbBuy.setChecked(p.box);
return view;
}
Product getProduct(int position) {
return ((Product) getItem(position));
}
ArrayList<Product> getBox() {
ArrayList<Product> box = new ArrayList<Product>();
for (Product p : objects) {
if (p.box)
box.add(p);
}
return box;
}
OnCheckedChangeListener myCheckChangList = new OnCheckedChangeListener() {
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
getProduct((Integer) buttonView.getTag()).box = isChecked;
}
};
}
OnItemClickListener and OnItemLongClickListener didn't function at all. Anyone help me out here.. I did diagnose the problem but it still doesn't have function
OnItemClickListener itemListener = new OnItemClickListener() {
OnItemLongClickListener itemLongListener = new OnItemLongClickListener() {
You just define those variables but you don't assign them to your ListView.
You should call these lines somewhere:
lvMain.setOnItemClickListener(itemListener);
lvMain.setOnItemLongClickListener(itemLongListener);
UPDATE:
You also miss to register the list for context menu.
registerForContextMenu(lvMain);
implement View.OnItemClickListener and AdapterView.OnItemLongClickListener and their corresponding methods in your class.
initialize your views correctly (findViewById...)
set click listeners to your views (button.setOnClickListener(this) / button.setOnLongClickListener(this)
react to the push events in the implemented methods like:
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.button:
this.doSomething();
}
}
and
#Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
//react to the view or react to the position
switch (view.getId()) {
case R.id.button:
this.doSomething();
}
return true;
}
You need to register listeners. Add following lines to the end of your onCreate() method.
lvMain.setOnItemClickListener(itemListener);
lvMain.setOnItemLongClickListener(itemLongListener);
I had the exact same problem. When onclick or onlongclick are enabled in the Layout; onitemclickListener wont work. Just remove the tags android:clickable and android:longclickable from your Layout XML resource and it will all work.
I want to make an app which includes a listView with check boxes and a two buttons named add and delete selected. I want to delete all the item that are checked in the list view.I am unable to do that despite of my lot of efforts. Any help would be appreciated.
Here is my code
package com.example.chkbokinlistview;
public class Adapter extends ArrayAdapter<Movies> {
ArrayList<Movies> data;
Context context;
int id;
private Holder h;
public Adapter(Context context, int textViewResourceId, ArrayList<Movies> objects) {
super(context, textViewResourceId, objects);
this.data = objects;
this.context = context;
this.id = textViewResourceId;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
final int p = position;
View v = convertView;
LayoutInflater l = ((Activity)context).getLayoutInflater();
h = new Holder();
if (v == null) {
v = l.inflate(id, parent, false);
h.tv = (TextView) v.findViewById(R.id.textView1);
h.cb = (CheckBox) v.findViewById(R.id.checkBox1);
v.setTag(h);
}else{
h = (Holder) v.getTag();
h.cb.setChecked(true);
}
h.tv.setText(data.get(position).movieName);
h.cb.setChecked(data.get(position).deleted);
return v;
}
public void delete(){
//how to delete all the items that are checked
}
class Holder{
TextView tv;
CheckBox cb;
}
}
MainActivity.java
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv = (ListView) findViewById(R.id.lv);
bDelete = (Button) findViewById(R.id.bDelete);
bAdd = (Button) findViewById(R.id.bAdd);
list = new ArrayList<Movies>();
a = new Adapter(this, R.layout.listitem, list);
lv.setAdapter(a);
bDelete.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
a.delete();
}
});
bAdd.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
final EditText et = new EditText(MainActivity.this);
dialog = new AlertDialog.Builder(MainActivity.this)
.setPositiveButton("OK", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface arg0, int arg1) {
// TODO Auto-generated method stub
list.add(new Movies(et.getText().toString(), false));
a.notifyDataSetChanged();
dialog.dismiss();
}
})
.setTitle("ADD Movie")
.setView(et)
.create();
dialog.show();
}
});
}
On checking the checkbox add that position in an ArrayList let say toBeDeleted, and when you click delete button, just remove items from your ArrayList named data according to the positions that you have in toBeDeleted and call the adapter method notifyDataSetChanged().
Add a checkedChangedListener in the getView method for your CheckBox.
h.cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton arg0,
boolean arg1) {
// TODO Auto-generated method stub
if (arg1) {
list.add(position);
} else {
for (int i = 0; i < list.size(); i++) {
if (list.get(i) == position) {
list.remove(i);
break;
}
}
}
}
});
Where list is a ArrayList<Integer>,
and for deleting
private void delete() {
for(int i = 0 i<list.size;i++)
data.remove(list.get(i));
}
but before deleting you have to sort the list in decending order, in order to remove correctly, otherwise you may get an IndexOutofBoundException