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Update list view after navigating back to previous activity

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

Pass Data from Dialog to new Activity

I am trying pass data from my dialog box to a new Activity. So basically what i want to do for example in my Dialog box i have Name: John, when i click on my okay button it opens a new activity but i want that John to be set in my edit box on my new activity:
Here is my Activity where my Dialog box code is:
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
/** To change selected state view */
view.setSelected(true);
HashMap<String, Object> obj = (HashMap<String, Object>) ADAhere.getItem(position);
String SlectedName = (String) obj.get("NAME");
String SlectedPrice = (String) obj.get("PRICE");
String SlectedSize = (String) obj.get("SIZE");
String SlectedRange = (String) obj.get("RANGE");
String SlectedSupp = (String) obj.get("SUPPLIER");
// Toast.makeText(getActivity().getApplicationContext(), SlectedName, Toast.LENGTH_SHORT).show();
final Dialog dialog = new Dialog(getActivity());
dialog.getWindow();
//dialog.setTitle("Confirm your Vote");
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.diaglog);
final TextView VName = (TextView) dialog.findViewById(R.id.Name);
final TextView VRange = (TextView) dialog.findViewById(R.id.Range);
final TextView VSUPPLIER = (TextView) dialog.findViewById(R.id.Supplier);
final TextView VSIZE = (TextView) dialog.findViewById(R.id.Size);
final TextView VPrice = (TextView) dialog.findViewById(R.id.Price);
VName.setText(SlectedName);
VRange.setText(SlectedRange);
VSUPPLIER.setText(SlectedSupp);
VSIZE.setText(SlectedSize);
VPrice.setText(SlectedPrice);
dialog.show();
Button cancelBtn = (Button) dialog.findViewById(R.id.cancel_btn);
cancelBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
dialog.dismiss();
}
});
Button UpdateBtn = (Button) dialog.findViewById(R.id.btn_update);
UpdateBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(getActivity().getApplicationContext(),Upvalence.class);
startActivity(i);
}
});
Button deleteBtn = (Button) dialog.findViewById(R.id.btn_delete);
deleteBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(getActivity().getApplicationContext(),Upvalence.class);
startActivity(i);
}
});
dialog.show();
}
});
so i want to pass VName.setText(SlectedName); to a new activity:
name1.setText(dialogactivityname);

Pass in as an extra:
instead of:
Intent i = new Intent(getActivity().getApplicationContext(),Upvalence.class);
startActivity(i);
you should pass in the name
Intent i = new Intent(getActivity().getApplicationContext(),Upvalence.class);
i.putExtra("string", SlectedName);
startActivity(i);
Then, on your Upvalence activity:
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
Bundle arguments = this.getIntent().getExtras();
String yourString = arguments.getString("string");
}

Pass value from first activity to third activity into a listview overrides old value

I have an app, where a user can enter a number and save to listView. The app is split into 3 activities.
The first activity is the MainActivity, which does something else. The second activity is where I enter a number and save it. The code Is below
public class HomeTeamScored extends Activity {
protected static EditText display;
protected static ArrayAdapter<String> adapter;
Button addButton;
CheckBox checkBox;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.rect_activity_home_goal_player);
display = (EditText) findViewById(R.id.editText);
addButton = (Button) findViewById(R.id.btn);
checkBox = (CheckBox) findViewById(R.id.checkBox);
adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1);
addButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String task = display.getText().toString();
adapter.add(task);
adapter.notifyDataSetChanged();
SavePreferences();
Intent i = new Intent(HomeTeamScored.this, MainActivity.class);
startActivity(i);
finish();
}
});
}
protected void SavePreferences() {
// TODO Auto-generated method stub
SharedPreferences data = getApplicationContext().getSharedPreferences("saveNumber", android.content.Context.MODE_PRIVATE);
SharedPreferences.Editor editor = data.edit();
for (int i = 0; i < adapter.getCount(); ++i){
// This assumes you only have the list items in the SharedPreferences.
editor.putString(String.valueOf(i), adapter.getItem(i));
}
editor.commit();
}
}
In my third activity, I retrieve the saved number.
public class ScoreBoardOverview extends Activity {
ListView lv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.rect_activity_score_board_overview);
adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1);
lv = (ListView) findViewById(R.id.listView);
adapter.notifyDataSetChanged();
lv.setAdapter(adapter);
loadPreferences();
}
protected void loadPreferences(){
SharedPreferences data = getApplicationContext().getSharedPreferences("saveNumber", Context.MODE_PRIVATE);
for (int i = 0;; ++i){
final String str = data.getString(String.valueOf(i), "");
if (!str.equals("")){
adapter.add(str);
} else {
break; // Empty String means the default value was returned.
}
}
}
}
All this is working fine, and it adds a number to listView, but the problem is that it overrides the old value, were instead it should add a second row.
Anyone who can help??

adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1);
addButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String task = display.getText().toString();
adapter.add(task);
adapter.notifyDataSetChanged();
SavePreferences();
Intent i = new Intent(HomeTeamScored.this, MainActivity.class);
startActivity(i);
finish();
}
});
}
here your adapter item size will be 0 when you call second activity each time. if you want to add second or third item you should write your
protected void loadPreferences(){
SharedPreferences data = getApplicationContext().getSharedPreferences("saveNumber", Context.MODE_PRIVATE);
for (int i = 0;; ++i){
final String str = data.getString(String.valueOf(i), "");
if (!str.equals("")){
adapter.add(str);
} else {
break; // Empty String means the default value was returned.
}
}
}
method in second activity too. and call loadPreferences() after this line
adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1);
your adapter data size will be changed.

Android studio pass ListView to another activity

I am trying to pass an array list to another activity but it seems that is not enough. I searched all day to pass the array list with "intent" but with no success. I wrote a code for learning purposes. How to pass the data and show the Arraylist in a second activity?
The action button is btn_save. If you want further details let me know.
The code is in
MainActivity (first activity):
public class MainActivity extends AppCompatActivity {
ArrayList<String> addArray = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final EditText editTextOne = (EditText) findViewById(R.id.editTextOne);
final EditText editTextTwo = (EditText) findViewById(R.id.editTextTwo);
Button btn_showText = (Button) findViewById(R.id.buttonShow);
final TextView textView = (TextView) findViewById(R.id.textResults);
Button btn_refresh = (Button) findViewById(R.id.btn_refresh);
Button btn_close = (Button) findViewById(R.id.btn_close);
Button btn_save = (Button) findViewById(R.id.btn_save);
final ListView showMe = (ListView) findViewById(R.id.list_items);
btn_showText.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String text = editTextOne.getText().toString();
String textTwo = editTextTwo.getText().toString();
if (text.length() == 0 || textTwo.length() == 0){
textView.setText("You must enter Name & Surname");
}else {
textView.setText(Html.fromHtml(
"<font color=\"red\">"+ text + "</font> " +
"<font color=\"blue\"><b>" + textTwo + " </b></font>"));
}
}
});
btn_refresh.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
startActivity(getIntent());
}
});
btn_close.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
System.exit(0);
}
});
btn_save.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Context context = getApplicationContext();
// CharSequence mytext = "Hahahaha";
// int duration = Toast.LENGTH_SHORT;
// Toast toast = Toast.makeText(context,mytext,duration);
// toast.show();
String text = editTextOne.getText().toString();
String textTwo = editTextTwo.getText().toString();
String getInput = text + textTwo;
if (addArray.contains(getInput)){
Toast.makeText(getBaseContext(), "Item already Added!", Toast.LENGTH_LONG).show();
}
else if (getInput == null || getInput.trim().equals("")){
Toast.makeText(getBaseContext(), "Input field is empty", Toast.LENGTH_LONG).show();
}
else{
addArray.add(getInput);
ArrayAdapter<String> adapter = new ArrayAdapter<>(MainActivity.this, android.R.layout.simple_list_item_1, addArray);
showMe.setAdapter(adapter);
Intent intent = new Intent(MainActivity.this, ListOfNames.class);
((EditText)findViewById(R.id.editTextOne)).setText(" ");
((EditText)findViewById(R.id.editTextTwo)).setText(" ");
}
}
});
}
public void onButtonClick(View v){
if (v.getId() == R.id.btn_list){
Intent i = new Intent(MainActivity.this, ListOfNames.class);
startActivity(i);
}
}
}
ListOfNames second activity: (almost empty)
public class ListOfNames extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.list_screen);
}
}

If you are trying to pass a arraylist of string then it will be easy. Just pass arraylist with intent like this:
ArrayList<String> list = new ArrayList<String>();
Intent intent = new Intent(ActivityOne.this, ActivityTwo.class);
intent.putStringArrayListExtra("key", list);
startActivity(intent);
And receive it in ActivityTwo like this:
ArrayList<String> list = getIntent().getStringArrayListExtra("key");

I found a temporary solution for this (The app is not broke). The only problem is the arraylist didn't increased. It contains and show only the last value.
Main Activity:
...
else{
// addArray.add(getInput);
// ArrayAdapter<String> adapter = new ArrayAdapter<>(MainActivity.this, android.R.layout.simple_list_item_1, addArray);
// showMe.setAdapter(adapter);
Intent intent = new Intent(MainActivity.this, ListOfNames.class);
intent.putExtra("data", getInput);
startActivity(intent);
// ((EditText)findViewById(R.id.editTextOne)).setText(" ");
// ((EditText)findViewById(R.id.editTextTwo)).setText(" ");
}
...
ListOfNames (Second Activity):
public class ListOfNames extends Activity {
ArrayList<String> addArrayT = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.list_screen);
Bundle bundle = getIntent().getExtras();
String data = bundle.getString("data");
Button btn_more = (Button) findViewById(R.id.btn_more);
ListView showMe = (ListView) findViewById(R.id.list_items);
addArrayT.add(data);
ArrayAdapter<String> adapterT = new ArrayAdapter<>(ListOfNames.this, android.R.layout.simple_list_item_1, addArrayT);
showMe.setAdapter(adapterT);
}
public void onClickMore(View v){
if (v.getId() == R.id.btn_more){
Intent i = new Intent(ListOfNames.this, MainActivity.class);
startActivity(i);
}
}
}

AlertDialog and soft keyboard

I am developing an android application. I am using the alertDialog class. Where I have a custom listview and 2 buttons. In my custom listview I have an EditText Field. But when the dialog pops and I touch the EditText while the cursor starts flashing in the Textbox the softKeyboard doesn't appear. Is it because of the alertdialog?
public class ProgressReport extends ListActivity {
private ResultSet receivedData;
private StudentProgressAdapter ca;
private Button btnRtn;
ArrayList<String> content =new ArrayList<String>();
ArrayList<String> subContent = new ArrayList<String>();
AlertDialog dialog ;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setTheme(android.R.style.Theme_Holo_Light);
setContentView(R.layout.examslayout);
for(int i =0;i<20;i++)
content.add("ELEMENTARY: "+i);
for(int i =0;i<20;i++)
subContent.add("ΒΑΣΙΚΗ ΚΑΤΗΓΟΡΙΑ");
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Student Stats").setPositiveButton("Yes",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
// if this button is clicked, close
// current activity
//MainActivity.this.finish();
}
})
.setNegativeButton("No",new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
// if this button is clicked, just close
// the dialog box and do nothing
dialog.cancel();
}
});;
ListView modeList = new ListView(this);
modeList.setAdapter(new ProgressReportAdapter2(this, new int[]{R.layout.arrowlistview}, new int[]{R.id.textView1,R.id.textView2},content,20,subContent));
builder.setView(modeList);
dialog = builder.create();
dialog.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE|WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM);
Intent intent = getIntent();
receivedData = (ResultSet) intent.getSerializableExtra("SentData");
ArrayList<String> content = new ArrayList<String>(MainPagerActivity.receivedData.getStudents().length);
for (int i=0; i <receivedData.getStudents().length; i++)
content.add(receivedData.getStudents()[i].getProperty(3).toString()+" "+receivedData.getStudents()[i].getProperty(2).toString());
ca= new StudentProgressAdapter(this, new int[]{R.layout.stdprgrlistview}, new int[]{R.id.textView1}, content,content.size());
setListAdapter(ca);
btnRtn= (Button) findViewById(R.id.btn);
btnRtn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
finish();
}
});
}
#Override
public void onListItemClick(ListView l, View v, int position, long id) {
dialog.show();
}

Try this:
AlertDialog alertToShow = alert.create();
alertToShow.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
alertToShow.show();
Update:
you can modify your code like this
dialog = builder.create();
dialog.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
dialog.show();
Hope this helps.

After the creation of the dialog add :
dialog.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE|WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM);`