Develop Reference

Android spinners dynamic data binding

I am new to android , I have an activity with 3 multiple spinners as bellow
Spinner 1:department
Spinner2:semester
Spinner3:subjects
and one button
spinner1 shows the department on select of department it has to display the semester on select of semester it has to display the subject spinner
NOTE:-SUBJECT SPINNER DEPENDS ON THE SELECTION OF SEMESTER SPINNER AS WELL AS DEPARTMENT SPINNER.
something like country, state, city spinners but suggest me some other ideas to do it because i am using string resources to list the items of spinners
Please help me

Try something like this in your activity.
Firstly, make your activity implement AdapterView.OnItemSelectedListener & View.OnClickListener.
private Spinner mDepartmentSpinner;
private Spinner mSemesterSpinner;
private Spinner mSubjectSpinner;
private Button mButton;
// Values to fill first spinner with.
private String[] mDepartments = {
"Department 1",
"Department 2",
"Department 3",
"Department 4",
};
private String[] mSemesters;
private String[] mSubjects;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initViews();
}
private void initViews() {
// Find the spinners and button, declared in the activity's resource file
mDepartmentSpinner = (Spinner) findViewById(R.id.department_spinner);
mSemesterSpinner = (Spinner) findViewById(R.id.semester_spinner);
mSubjectSpinner = (Spinner) findViewById(R.id.subject_spinner);
mButton = (Button) findViewById(R.id.button);
// Initialise spinner with values, placing them into a textview
mDepartmentSpinner.setAdapter(new ArrayAdapter<String>(getContext(), R.layout.text_view, mDepartments));
// Attach a listener for item selection
departmentSpinner.setOnItemSelectedListener(this);
}
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
// Work out which spinner was selected
switch (view.getId()) {
case R.id.department_spinner:
// Get the selected item
String selectedDepartment = mDepartments[position];
// Get values to fill the semester spinner with, based on initial selection.
mSemesters = getSemestersFor(selectedDepartment);
// Initialise spinner with values, placing them into a textview
mSemesterSpinner.setAdapter(new ArrayAdapter<String>(getContext(), R.layout.text_view, mSemesters));
// Attach a listener for item selection
mSemesterSpinner.setOnItemSelectedListener(this);
break;
case R.id.semester_spinner:
// Get the selected item
String selectedSemester = mSemesters[position];
// Get values to fill the subject spinner with, based on second spinner selection.
mSubjects = getSubjectsFor(selectedSemester);
// Initialise spinner with values, placing them into a textview
mSubjectSpinner.setAdapter(new ArrayAdapter<String>(getContext(), R.layout.text_view, subjects));
// Attach a listener for item selection
mSubjectSpinner.setOnItemSelectedListener(this);
break;
case R.id.subject_spinner:
mButton.setOnClickListener(this);
break;
}
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
mButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(getApplicationContext(), "Please select an option from each spinner.", Toast.LENGTH_LONG).show();
}
});
}
#Override
public void onClick(View v) {
// Go to your new activity, passing the selected subject
Intent intent = new Intent(this, SubjectActivity.class);
intent.putExtra("KEY_SUBJECT", (String) mSubjectSpinner.getSelectedItem());
startActivity(intent);
}
You can get the selected subject in the SubjectActivity like so...
#Override
public void onCreate(Bundle savedInstanceState) {
if (getIntent().getExtras().containsKey("KEY_SUBJECT") {
String subject = getIntent().getExtras().getString("KEY_SUBJECT");
}
}
Code for R.layout.text_view
<?xml version="1.0" encoding="utf-8"?>
<TextView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
You will need to implement the following methods yourself, I don't know your logic!
private String[] getSemestersFor(String department) {
// your code here
}
private String[] getSubjectsFor(String semester) {
// your code here
}

How to add a pop up/Dialog box and pass information back to the class in Android

I am trying to create a pop-up dialog to allow the user of my android app to add a new field to a list on their main page.
I've done a bit of research and found the Dialog/alertDialog option, but i haven't been able to get it working correctly.
Here is my MainActivity class:
public class MainActivity extends Activity {
private ListView listView;
public static ArrayList<String> ArrayofName = new ArrayList<String>();
//final Dialog dialog = new Dialog(this); //!!! ERROR HERE !!! //
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DatabaseHandler db = new DatabaseHandler(this);
Button AddNewStudent = (Button) findViewById(R.id.AddNew);
/**
* CRUD Operations
* */
// Inserting Contacts
Log.d("Insert: ", "Inserting ..");
//db.addStudentProfile(new StudentProfile("Shannon", "White"));
//db.addStudentProfile(new StudentProfile(1,"Shannon", "White", "WhitehousePS", "30", "21" ));
/*AddNewStudent.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
// Using an alertDialog to get the user to enter in a new Student
dialog.setContentView(R.layout.add_new_student);
dialog.setTitle("Add a new student");
final EditText firstName=(EditText)dialog.findViewById(R.id.firstName);
final EditText surname=(EditText)dialog.findViewById(R.id.surname);
final EditText school=(EditText)dialog.findViewById(R.id.school);
final EditText age=(EditText)dialog.findViewById(R.id.age);
Button save=(Button)dialog.findViewById(R.id.save);
Button btnCancel=(Button)dialog.findViewById(R.id.cancel);
dialog.show();
}
});*/
// Reading all contacts
Log.d("Reading: ", "Reading all contacts..");
List<StudentProfile> contacts = db.getAllStudents();
for (StudentProfile studProf : contacts) {
String log = "Id: "+studProf.getID()+" , First name: " + studProf.getFirstName() + ", Surname: " + studProf.getSurname() + ", School: " + studProf.getSchool() +
", Reading Level: "+ studProf.getReadingLevel() + ", Age: " + studProf.getAge();
// Writing Contacts to log
Log.d("Name: ", log);
}
db.getAllStudents();
listView = (ListView) findViewById(R.id.listView1);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, ArrayofName);
listView.setAdapter(adapter);
listView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
Toast.makeText(getApplicationContext(),
((TextView) v).getText(), Toast.LENGTH_SHORT).show();
}
});
}
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
// Get the layout inflater
LayoutInflater inflater = getActivity().getLayoutInflater();
// Inflate and set the layout for the dialog
// Pass null as the parent view because its going in the dialog layout
builder.setView(inflater.inflate(R.layout.dialog_signin, null))
// Add action buttons
.setPositiveButton(R.string.signin, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int id) {
// sign in the user ...
}
})
.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
LoginDialogFragment.this.getDialog().cancel();
}
});
return builder.create();
}
}
It's linked to a very simple xml page that just has editible text fields.
My application won't even open with this code - i have tracked the issue down to this line:
final Dialog dialog = new Dialog(this);
at the top of my program.
IS this the best way to go about making a pop up dialog?
Also, what is the easiest way to pass the information back to the class to be stored in a database?
Any help would be much appreciated, thanks! :)

You can create some private variables at the top of your class, and get the text from the editText and put it into those variables in the dialog's button click handler method (where you have the 'sign in the user' comment.)
Sometimes it's also easyer to crate a dialog themed activity.

Get values of multiple checkboxes on Android

I have one of these for each day of the week:
mondayRadioButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (mondayRadioButton.isChecked()){
deleteAppointmentsLayout.removeAllViews();
daySelected = 1;
for(Iterator<Appointment> i = appointments.iterator(); i.hasNext();){
Appointment item = i.next();
if(item.getDay() == 1){
checkBox = new CheckBox(DeleteAppointmentActivity.this);
System.out.println("fucken did work");
id = item.getId();
time = item.getTime();
duration = item.getDuration();
description = item.getDescription();
boxText = time + ", " + duration + ", " + description;
checkBox.setText(boxText);
checkBox.setTextSize(12);
checkBox.setId((int) id);
deleteAppointmentsLayout.addView(checkBox);
}
else {
System.out.println("fucken didnt work");
}
}
}
}
});
When an onclick for a button is activated I want to retrieve the information for each of the selected checkboxes for the currently selected day (checkboxes are generated programmatically). How can I check which ones are selected when the onclick for the Delete button is activated?

Create a member variable Array like
public class MyClass extends Activity
{
ArrayList<CheckBox> cbArray = new ArrayList<CheckBox>();
then when you create a checkbox add it to the ArrayList. Now when you click the delete Button use a for loop to iterate over the ArrayList and call isChecked() on each one.
Then delete or add that to a checked Array to do whatever you need with it
for (int i=0; i<cbArray.size(); i++)
{
if (cbArray.get(i).isChecked())
{
// do whatever here

Populate Spinner from CSV File using Scanner

Using Android (Eclipse) I am trying to read a .csv file and dynamically
populate a Spinner using Scanner. Have tried many methods with the same result.
Emulator shows Spinner but only the last comma and price are populated. Also need to
store all three variables in array and retrive them when Spinner selection is made
in order to populate EditText fields. Any assistance would be greatly appreciated...
Data file records:
4,Aluminum Cans,.55 5,Vehicle with cat convertor,9.00 18,Brass ( Irony Red/Yellow ),.20 1001,Deduction Customer # Look-Up,-2.00
Java:
public class BRprogramActivity extends Activity {
private static final String TAG = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//
Button addButton;
Button editButton;
Button sendButton;
//
Spinner array_spinner;
//
// activate soft Keyboard
this.getWindow().setSoftInputMode
(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
//
// .csv comma separated values file
//
try {
Scanner scanner = new Scanner(getResources().openRawResource(R.raw.brdata));
//
while (scanner.hasNext()) {
String data = (scanner.next());
String [] values = data.split(",");
item = values[0];
description = values[1];
price = values[2];
//
array_spinner = (Spinner)findViewById(R.id.spinner1);
ArrayAdapter<String> adapter = new ArrayAdapter<String>
(this,android.R.layout.simple_spinner_item,values);
array_spinner.setAdapter(adapter);
}
scanner.close();
} catch (Exception e) {
Log.e(TAG, "Exception: "+Log.getStackTraceString(e));
}
//
addButton = (Button) findViewById(R.id.addbutton);
addButton.setOnClickListener(new OnClickListener(){
public void onClick(View v){
Log.v("test", "ADD button clicked");
}
});
//
editButton = (Button) findViewById(R.id.editbutton);
editButton.setOnClickListener(new OnClickListener(){
public void onClick(View v){
Log.v("test", "EDIT button clicked");
}
});
//
sendButton = (Button) findViewById(R.id.sendbutton);
sendButton.setOnClickListener(new OnClickListener(){
public void onClick(View v){
Log.v("test", "SEND button clicked");
}
});
}
}

If you want to display each row of your CSV on one row in the spinner, try this:
List<String> list = new ArrayList<String>();
while (scanner.hasNext()) {
list.add(scanner.next());
}
array_spinner = (Spinner)findViewById(R.id.spinner1);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list);
array_spinner.setAdapter(adapter);
Though has poor readability for the ordinary user, perhaps you only want to display the description and price:
List<String> list = new ArrayList<String>();
while (scanner.hasNext()) {
String data = scanner.next();
String [] values = data.split(",");
list.add(values[1] + " $" + values[2]);
}
Your posted method only showed the last CSV line, because you were creating a new ArrayAdapter for each line in the CSV and overriding the previous adapter that you had created.
By storing the Scanner's results in a List and moving the adapter's definition out of the Scanner loop, you should be able to see results like you had hope.
Addition from comments
An OutOfBounds exception with length=2, index=2 suggests that at least one row in your real CSV only has two values (one comma). To help you find that row try this:
if(values.length != 3)
Log.v("Example", "Malformed row: " + data);
else
list.add(values[1] + " $" + values[2]);
Also, I neglected to mention that you are not setting a drop down layout for your Spinner. This will not cause the app to crash, but this creates the standard user interface:
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

Spinner delete items

I have developed an application in which i have one edit text value of edit text is entered in spinner on button clicked an the item i select to delete gets deleted but the problem is that when i delete the last item of spinner whole spinner list flushes . i want to delete only selected item(only last item)
My code is as follows :
#Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main);
///////////////////////////////////////////////////////////////
// grab our UI elements so we can manipulate them (in the case of the
// Spinner)
// or add listeners to them (in the case of the buttons)
m_myDynamicSpinner = (Spinner) findViewById(R.id.dynamicSpinner);
m_addItemText = (EditText) findViewById(R.id.newSpinnerItemText);
Button addButton = (Button) findViewById(R.id.AddBtn);
Button clearButton = (Button) findViewById(R.id.ClearBtn);
// //////////////////////////////////////////////////////////////
// create an arrayAdapter an assign it to the spinner
m_adapterForSpinner = new ArrayAdapter(this,
android.R.layout.simple_spinner_item);
((ArrayAdapter) m_adapterForSpinner)
.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
m_myDynamicSpinner.setAdapter(m_adapterForSpinner);
// m_adapterForSpinner.add("dummy item");
// //////////////////////////////////////////////////////////////
// add listener for addButton
addButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
addNewSpinnerItem();
}
});
clearButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
clearSpinnerItems();
}
});
}
// //////////////////////////////////////////////////////////////
// add listener for addButton
private void addNewSpinnerItem() {
Log.v("TAG", "addNewSpinnerItems called");
if (m_addItemText.getText().length() == 0) {// ||(m_addItemText.getText().toString()==
// " ")){
Log.v("In if cndtn", "textHolder is of length 0");
Toast.makeText(getApplicationContext(), "The textView is empty",
Toast.LENGTH_LONG).show();
//m_myDynamicSpinner.clearFocus();
//m_myDynamicSpinner.setFocusable(false);
//m_addItemText.setFocusable(true);
} else {
CharSequence textHolder = "" + m_addItemText.getText();
// else{
Log.v("else", textHolder + "");
// m_adapterForSpinner.add(textHolder);
// }
((ArrayAdapter) m_adapterForSpinner).add(textHolder);
}
m_addItemText.setText("");
}
private void clearSpinnerItems() {
// m_adapterForSpinner.clear();
Log.v("TAG", "clearSpinnerItems called");
m_myDynamicSpinner
.setOnItemSelectedListener(new OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent,
View view, int pos, long id) {
// TODO Auto-generated method stub
Log.v("TAG", "Itemseleted to be removed is "
+ m_adapterForSpinner.getItem(pos).toString());
Log.v("Position of item", pos + "");
Object t = m_adapterForSpinner.getItem(pos);
Log.v("Object t ", (String) t);
((ArrayAdapter) m_adapterForSpinner).remove((CharSequence) t);
Log.v("Item removed", t + "");
// m_myDynamicSpinner.setSelected(false);
}
#Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
// m_adapterForSpinner.add("dummy item");
}

for delete all items use:
mySpinner.setAdapter(null);
if you want to delete a particular item, remove this from m_adapterForSpinner and then:
mySpinner.setAdapter(m_adapterForSpinner);

Remember: methods "remove" and "clear" do not work with ArrayAdapter for Android 2.3.3 and lower. You'll receive error message "Unsupported operation.... bla bla bla". May be they work with Android 4.0 and up, I don't know.
Here is my solution which works even with minSdkVersion="5".
Create Spinner and fill it with test data
This code is in an activity form. Use ArrayList as data source for ArrayAdapter instead of array. It's important because you'll use its "remove" method later
List<String> reportFiles = new ArrayList<String>();
//fill some test data
reportFiles.add("aaaaaaaaaaaaa");
reportFiles.add("bbbbbbbbbbbbb");
reportFiles.add("ccccccccccccc");
//create spinner from corresponding layout xml file
Spinner spnReport = (Spinner) findViewById(R.id.spinner_report);
//create ArrayAdapter
ArrayAdapter reportAdapter = new ArrayAdapter(this,
android.R.layout.simple_spinner_dropdown_item, reportFiles);
//set adapter to spinner
spnReport.setAdapter(reportAdapter);
//select first item in adapter - is not obligatory
spnReport.setSelection(0);
Remove selected item from Spinner
reportFiles.remove((String)spnReport.getSelectedItem());
//create new ArrayAdapter with modified ArrayList
reportAdapter = new ArrayAdapter(this,android.R.layout.simple_spinner_dropdown_item,reportFiles);
//set new array adapter to spinner
spnReport.setAdapter(reportAdapter);
//select first item
spnReport.setSelection(0);

For me the accepted answer throwed an exception so what I did was this.
ArrayAdapter adapter = new ArrayAdapter<>(getActivity(),
android.R.layout.simple_spinner_item, Collections.emptyList());
spinner.setAdapter(adapter);

I had the same problem. Doing this did solve the problem, by emptying the spinner:
mySpinner.setSelection(Adapter.NO_SELECTION);