I can't seem to figure out what is wrong with this code. When I click a list item to open the delete dialog, it won't do anything. Though if I restart the activity, all items will be deleted.
public class ContextsList extends Activity {
EditText display;
ListView lv;
public ArrayAdapter<String> adapter;
Button addButton;
String temp_appender;
String appender = "";
List<String> dataset;
String[] splitup;
public String items;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.contexts_list);
display = (EditText) findViewById(R.id.editText);
lv = (ListView) findViewById(R.id.listView);
addButton = (Button) findViewById(R.id.bAdd);
LoadPreferences();
lv.setAdapter(adapter);
LoadPreferences();
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1);
addButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
appender = LoadPreferences();
if(display.getText().toString() != null){
temp_appender = display.getText().toString();
String string_to_split = appender + "," + temp_appender;
List<String> items = Arrays.asList(string_to_split.split(","));
adapter = new ArrayAdapter<String>
(getApplicationContext(), android.R.layout.simple_list_item_1, items);
lv.setAdapter(adapter);
adapter.notifyDataSetChanged();
SavePreferences("LISTS", string_to_split);
LoadPreferences();
}
display.setText("");
}
});
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
deleteItem(arg1);
}
});
}
protected void deleteItem(final View arg1)
{
AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);
dialogBuilder.setTitle("Delete");
dialogBuilder.setMessage("Do you want to delete \"" +
((TextView) arg1).getText() + "\"?");
dialogBuilder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
items = LoadPreferences();
try {
adapter.remove(((TextView) arg1).getText().toString());
adapter.notifyDataSetChanged();
SavePreferences("LISTS", items);
} catch (Exception ignored) {
}
SavePreferences("LISTS", items);
}
});
dialogBuilder.setNeutralButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
}
});
AlertDialog deleteDialog = dialogBuilder.create();
deleteDialog.show();
}
protected void SavePreferences(String key, String value) {
// TODO Auto-generated method stub
SharedPreferences data = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor = data.edit();
editor.putString(key, value);
editor.commit();
}
protected String LoadPreferences(){
SharedPreferences data = PreferenceManager.getDefaultSharedPreferences(this);
String dataSet = data.getString("LISTS", "");
dataset = Arrays.asList(dataSet.split(","));
splitup = dataSet.split(",");
List<String> items = Arrays.asList(dataSet.split(","));
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, items);
lv.setAdapter(adapter);
adapter.notifyDataSetChanged();
return dataSet;
}
}
I've been at this for hours, so if anyone could help spot this error I'd really appreciate it. Just let me know if you need any more input from me.
Here is the answer
The reason is following: according to API the list is immutable in terms of adding/deletion. But on add operation you create a new adapter, so it runs well. But when you try to delete an object from "immutable" list, you get an error.
And please, never ever ever use empty catch block without clear explanation why it is empty. Just put ignored.printStackTrace(); is will save you a tonn of time!
Hai in my project i am doing list deletion. I am using like this. when the user click the list. please get the position of the list and pass through dialog function arg.
lv.remove(positiontoDelete);
Related
i want to get selected item from a spinner, and if, for example, Table 2 is selected, i want to change a ImageView's src to another image. here's what i've tried so far:
public class Tables extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tables);
Spinner dropdown = findViewById(R.id.spinner1);
ImageView imageView = findViewById(R.id.q1);
String[] items = new String[]{"Table 1", "Table 2"};
ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_dropdown_item, items);
dropdown.setAdapter(adapter);
String text = dropdown.getSelectedItem().toString();
if (text.equals("Table 1"))
{
imageView.setVisibility(View.VISIBLE);
}
if (text.equals("Table 2")){
imageView.setImageResource(R.drawable.i2);
}
}
}
You are looking for something like this to listen what was selected:
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
String items = spinner.getSelectedItem().toString();
if (items.equals("Table 1")){
imageView.setVisibility(View.VISIBLE);
} else if (items.equals("Table 2") {
imageView.setImageResource(R.drawable.i2);
}
#Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
Excuse my noobness. I just don't understand how to implement it to work with my code. What I'm doing is editing a name that's in a list view. When editing the name in "EditDeleteList" and get back to the previous activity (ListView) to see the name updated within the list view, nothing happens. I have to go out of the activity completely to see the change reflected. How do I get this to update? I implement an onActivityReult() method but then get this error message "java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference" so I removed it completely. How I could get the list view to update without getting that error message?
ListView.Java
public class ListView extends AppCompatActivity {
private static final String TAG = "ListView";
DatabaseHelper mDatabaseHelper;
Button btnAdd;
private EditText editText;
private android.widget.ListView listView;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list_view);
mDatabaseHelper = new DatabaseHelper(this);
btnAdd = (Button) findViewById(R.id.btnAdd);
editText = (EditText) findViewById(R.id.editText);
listView = (android.widget.ListView) findViewById(R.id.lv);
ArrayList<String> list = getIntent().getStringArrayListExtra("myList");
android.widget.ListView lv = (android.widget.ListView) findViewById(R.id.lv);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, list);
lv.setAdapter(adapter);
//Takes user back to the main activity
ImageView ivBack = (ImageView) findViewById(R.id.ivBackArrow);
ivBack.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.d(TAG, "onClick: pressed back arrow");
Intent intent = new Intent(ListView.this, MainActivity.class);
startActivity(intent);
}
});
btnAdd.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String newEntry = editText.getText().toString();
if (editText.length() != 0) {
addData(newEntry);
editText.setText("");
} else {
toastMessage("you must put something in the text field");
}
}
});
populateListView();
}
public void addData(String newEntry) {
boolean insertData = mDatabaseHelper.addData(newEntry);
if (insertData) {
toastMessage("Successfully inserted");
recreate();
} else {
toastMessage("Whoops, something went wrong");
}
}
private void toastMessage(String message) {
Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
}
private void populateListView() {
Log.d(TAG, "populateListView: displaying data in the listview");
//get data and append to list
Cursor data = mDatabaseHelper.getData();
ArrayList<String> listData = new ArrayList<>();
while(data.moveToNext()) {
//get the value from the database in column 1
//set it to the arraylist
listData.add(data.getString(1));
}
//create arraylist and set it to the adapter
ListAdapter adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, listData);
listView.setAdapter(adapter);
//set onclick listen to edit activity
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
String name = adapterView.getItemAtPosition(position).toString();
Log.d(TAG, "onItemClick: you clicked on " + name);
Cursor data = mDatabaseHelper.getItemID(name); //get the id associated with that name
int itemID = -1;
while (data.moveToNext()) {
itemID = data.getInt(0);
}
if (itemID > -1) {
Log.d(TAG, "onItemID: the ID is: " + itemID);
Intent editScreenIntent = new Intent(ListView.this, EditDeleteList.class);
editScreenIntent.putExtra("id",itemID);
editScreenIntent.putExtra("name",name);
startActivity(editScreenIntent);
} else {
toastMessage("No ID found");
}
}
});
}
}
EditDeleteList.java
public class EditDeleteList extends AppCompatActivity {
private static final String TAG = "EditDeleteList";
DatabaseHelper mDatabaseHelper;
private ImageView ivDelete;
private ImageView ivApprove;
private EditText editHashtag;
private String selectedName;
private int selectedID;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_edit_delete);
mDatabaseHelper = new DatabaseHelper(this);
editHashtag = (EditText) findViewById(R.id.editHashtag);
ivDelete = (ImageView) findViewById(R.id.ivDelete);
ivApprove = (ImageView) findViewById(R.id.ivApprove);
//get the intent extra from the ListView activity
final Intent receivedIntent = getIntent();
//get item ID passed as an extra
selectedID = receivedIntent.getIntExtra("id", -1);
//get name passed as an extra
selectedName = receivedIntent.getStringExtra("name");
//set text field to selected item text
editHashtag.setText(selectedName);
ivApprove.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String item = editHashtag.getText().toString();
if (!item.equals(null)) {
mDatabaseHelper.updateName(item, selectedID, selectedName);
} else {
toastMessage("you must enter a #hashtag");
}
finish();
}
});
}
private void toastMessage(String message) {
Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
}
}
In the EditDeleteList.java I have an onClickListener that saves the changes and goes back to the previous activity by using finish();
ivApprove.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String item = editHashtag.getText().toString();
if (!item.equals(null)) {
mDatabaseHelper.updateName(item, selectedID, selectedName);
} else {
toastMessage("you must enter a #hashtag");
}
finish();
}
});
Notify the adapter in some part of the activity lifecycle.
OnCreate() should not run when you go back (this is the reason you have to completely recreate the activity to see the list updated) so you should use OnRestart/OnStart/OnResume to notify the adapter to check for new items.
Check this image
I need an answer on how to create an add button to add listview item, and a delete button to delete last added item. Look at my code. I made an add button but that item exists only for a few seconds and every time I close that page (go to other activity in usermode) it is deleted. Please let me know how can I fix this code and how can I write code for delete button. I need to know how to delete last made item. Thanks for your help in advance. I am looking forward to reply.
public class dodaj extends Activity {
ListView lv;
SearchView sv;
EditText txtinput;
ArrayList<String> arrayList;
String[] recepies={};
ArrayAdapter<String> adapter;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dodaj);
registerClickCallback();
lv=(ListView) findViewById(R.id.listView);
sv=(SearchView) findViewById(R.id.searchView);
txtinput=(EditText)findViewById(R.id.txtinput);
Button addbutton=(Button)findViewById(R.id.addbutton);
Button buttondel=(Button) findViewById(R.id.buttondel);
arrayList= new ArrayList<>(Arrays.asList(recepies));
addbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick( View v ) {
String newItem=txtinput.getText().toString();
arrayList.add(newItem);
adapter.notifyDataSetChanged();
}
});
buttondel.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick( View v ) {
int i = arrayList.size()-1;
arrayList.remove(arrayList.get(i));
}
});
adapter=new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,arrayList);
lv.setAdapter(adapter);
sv.setOnQueryTextListener(new OnQueryTextListener() {
#Override
public boolean onQueryTextSubmit(String text) {
// TODO Auto-generated method stub
return false;
}
#Override
public boolean onQueryTextChange(String text) {
adapter.getFilter().filter(text);
return false;
}
});
}
private void registerClickCallback(){
lv=(ListView) findViewById(R.id.listView);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View viewClicked, int position, long id) {
TextView textView= (TextView) viewClicked;
if(position==0){
goToMojRecept1();
}else if(position==1){
goToMojRecept2();
}else if(position==2){
goToMojRecept3();
}else if(position==3){
goToMojRecept4();
}else if(position==4) {
goToMojRecept5();
}
}
});
}
private void goToMojRecept5() {
Intent intent = new Intent(this, MojRecept5.class);
startActivity(intent);
}
private void goToMojRecept4() {
Intent intent = new Intent(this, MojRecept4.class);
startActivity(intent);
}
private void goToMojRecept3() {
Intent intent = new Intent(this, MojRecept3.class);
startActivity(intent);
}
private void goToMojRecept2() {
Intent intent = new Intent(this, MojRecept2.class);
startActivity(intent);
}
private void goToMojRecept1() {
Intent intent = new Intent(this, MojRecept1.class);
startActivity(intent);
}
I have two fragment (AddAddressFragment,AddressFragment) and one DialogFragment. In my app i show alert box with radio button. If user choose anyone option, i want to pass that item to two fragment(AddressFragment and also AddAddressFragment). I can passed only one fragment(AddressFragment). How to pass the same value to another fragment(AddAddressFragment). I want to make list view in that AddAddressFragment
My code here:
RadioListAlert.java:
public class RadioListAlert extends DialogFragment {
CharSequence[] tag = { "Home", "Office", "Pg", "Others" };
private AddressListener addressListener;
private String itemClicked;
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setCancelable(true);
builder.setTitle("Please Tag Your Address").setSingleChoiceItems(tag, -1,
new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which)
{
Toast.makeText(getActivity(), tag[which],Toast.LENGTH_SHORT).show();
itemClicked = (String) tag[which];
}
}).setPositiveButton("Ok", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
if (addressListener != null)
addressListener.itemClicked(itemClicked);
//to dismiss the dialog after user choose an item and click ok, you can also add some validation before dismissing the dialog
dismiss();
}
}).setNegativeButton("Cancel",new DialogInterface.OnClickListener(){
#Override
public void onClick(DialogInterface dialog, int which) {
dismiss();
}
});
return builder.create();
}
public void setListener(AddressListener addressListener)
{
this.addressListener = addressListener;
}
public interface AddressListener
{
void itemClicked(String text);
}
}
AddressFragment.java:
public class AddressFragment extends Fragment implements RadioListAlert.AddressListener {
int position = 0;
EditText line1;
EditText line2;
EditText landmark;
AutoCompleteTextView cityText;
EditText zipcode;
Spinner country;
Spinner state;
RadioGroup tag;
Button savaddr;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_layout_address, container, false);
savaddr = (Button) view.findViewById(R.id.addrsave);
tag = (RadioGroup) view.findViewById(R.id.radioGroup);
line1 = (EditText) view.findViewById(R.id.line1);
line2 = (EditText) view.findViewById(R.id.line2);
cityText = (AutoCompleteTextView) view.findViewById(R.id.city_autoCompleteTextView);
zipcode = (EditText) view.findViewById(R.id.zipcode);
country = (Spinner) view.findViewById(R.id.countrySpinner);
state = (Spinner) view.findViewById(R.id.stateSpinner);
landmark = (EditText) view.findViewById(R.id.landmark);
// Get a reference to the AutoCompleteTextView in the layout
AutoCompleteTextView textView = (AutoCompleteTextView) view.findViewById(R.id.city_autoCompleteTextView);
// Get the string array
String[] city = getResources().getStringArray(R.array.city);
// Create the adapter and set it to the AutoCompleteTextView
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, city);
textView.setAdapter(adapter);
savaddr.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String addr1 = line1.getText().toString();
String addr2 = line2.getText().toString();
String addr_city = cityText.getText().toString();
String addr_zipcode = zipcode.getText().toString();
String addr_country = country.getSelectedItem().toString();
String addr_state = state.getSelectedItem().toString();
//Field Validation
if (Utility.isNotNull(addr1) && Utility.isNotNull(addr2) && Utility.isNotNull(addr_city) && Utility.isNotNull(addr_zipcode) && Utility.isNotNull(addr_country) && Utility.isNotNull(addr_state)) {
if (Utility.line2_validate(addr2)) {
if (Utility.line2_validate(addr_city)) {
//Show alert box with radio button option
RadioListAlert objRadioListAlert=new RadioListAlert();
objRadioListAlert.setListener(AddressFragment .this);
objRadioListAlert.show(getActivity().getFragmentManager(), "Radio Alert");
Toast.makeText(getActivity().getApplicationContext(), "Success.", Toast.LENGTH_SHORT).show();
} else {
cityText.setError("Enter valid City");
}
} else {
line2.setError("Enter valid Address");
}
} else {
Toast.makeText(getActivity().getApplicationContext(), "Please fill the form, don't leave any field blank", Toast.LENGTH_SHORT).show();
}
}
});
return view;
}
#Override
public void itemClicked(String text) {
((AccountActivity) getActivity()).navigatetoAddAddressActivity(text);
}
}
AddAddressFragment.java:
public class AddAddressFragment extends Fragment implements RadioListAlert.AddressListener {
ImageView add;
ListView addressListView;
private ArrayList<String> strArr;
private ArrayAdapter<String> adapter;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_layout_add_address, container,
false);
addressListView = (ListView) view.findViewById(R.id.address_list);
add = (ImageView)view.findViewById(R.id.add_address);
add.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
//((AccountActivity) getActivity()).navigatetoAddAddressActivity();
FragmentTransaction transaction = getFragmentManager().beginTransaction();
AddressFragment fragment = new AddressFragment();
transaction.replace(R.id.account_frame, fragment);
transaction.commit();
}
});
return view;
}
#Override
public void itemClicked(String text) {
Log.d("Welcome","Its worked");
Toast.makeText(getActivity().getApplicationContext(), "Item Clicked:" + text, Toast.LENGTH_SHORT).show();
strArr = new ArrayList<String>();
for (int i = 0; i < 2; i++) {
strArr.add(text + i);
adapter = new ArrayAdapter<String>(getActivity().getApplicationContext(),
android.R.layout.simple_list_item_1, strArr);
addressListView.setAdapter(adapter);
}
}
}
Please anyone help me!!
Thanks in advance!!!
You can use localbroadcast to send data between fragments
this is also handy when you want to send data from service to fragment or activity
how to use LocalBroadcastManager?
I'm trying to put onListItemClick, but when I start my app nothing happens with onListItemClick. Can anyone help me with this?
Here is my code:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
db = (new DatabaseHelper(this)).getWritableDatabase();
searchText = (EditText) findViewById(R.id.searchText);
employeeList = (ListView) findViewById(R.id.list);
Button searchButton = (Button) findViewById(R.id.searchButton);
searchButton.setOnClickListener(new OnClickListener() {
public void onClick(View view) {
search(employeeList);
}
});
}
public void search(View view) {
// || is the concatenation operation in SQLite
cursor = db
.rawQuery(
"SELECT _id, firstName, lastName, title FROM employee WHERE firstName || ' ' || lastName LIKE ?",
new String[] { "%" + searchText.getText().toString()
+ "%" });
adapter = new SimpleCursorAdapter(this, R.layout.employee_list_item,
cursor, new String[] { "firstName", "lastName", "title" },
new int[] { R.id.firstName, R.id.lastName, R.id.title });
employeeList.setAdapter(adapter);
}
public void onListItemClick(ListView parent, View view, int position, long id) {
Intent intent = new Intent(this, EmployeeDetails.class);
Cursor cursor = (Cursor) adapter.getItem(position);
intent.putExtra("EMPLOYEE_ID", cursor.getInt(cursor.getColumnIndex("_id")));
startActivity(intent);
}
}
There is no error messages and search is working normally.
employeeList = (ListView) findViewById(R.id.list);
add these line below the above line
employeeList = (ListView) findViewById(R.id.list);
employeeList .setOnItemClickListener(this);
Updated:: sample code
public class SampleActivity extends Activity implements OnItemClickListener{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(mWebView);
}
#Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,long arg3) {
// TODO Auto-generated method stub
}
}
register an OnItemClickListener() with setOnItemClickListener for your listview like this
listView.setOnItemClickListener(new OnItemClickListener() {
#Override public void onItemClick(AdapterView<?> adapter, View view, int pos, long id) {
Intent intent = new Intent(this, EmployeeDetails.class);
Cursor cursor = (Cursor) adapter.getItem(pos);
intent.putExtra("EMPLOYEE_ID", cursor.getInt(cursor.getColumnIndex("_id")));
startActivity(intent);
}
});
You have to register your listener as listview.setOnItemClickListener(this) in your code.
Try this
listview.setOnItemClickListener(new OnItemClickListener() {
// Your Code Goes Here
});