SimpleCursorAdapter + ListView: Checkboxes are lost when scrolling

Question

Checkboxes when caring for a screen lose their positions when returning. Here - SimpleCursorAdapter - the filter for the cursor is all the code (my question). How to implement a method to save boolean values? Really, instead of a cursor in the adapter, I need to send an array of boolean values? And how to take data through the cursor in the bindView () method? After all, I will remove the cursor, but it is needed.

Method for receiving data from the database

private void getProductList() { String filter = "list=" + intValue; final Cursor cursor = mSqLiteDatabase.query("products", new String[] {DatabaseProductHelper.PRODUCT_ID, DatabaseProductHelper.PRODUCT_NAME, DatabaseProductHelper.PRODUCT_COUNT, DatabaseProductHelper.PRODUCT_LIST, DatabaseProductHelper.PRODUCT_TYPE, DatabaseProductHelper.PRODUCT_COMPLETE}, null, null, null, null, null) ; final Cursor cursorc = mSqLiteDatabase.query("products", new String[] {DatabaseProductHelper.PRODUCT_ID, DatabaseProductHelper.PRODUCT_NAME, DatabaseProductHelper.PRODUCT_COUNT, DatabaseProductHelper.PRODUCT_LIST, DatabaseProductHelper.PRODUCT_TYPE, DatabaseProductHelper.PRODUCT_COMPLETE}, filter, null, null, null, null) ; final ArrayList<String> arrTblNames = new ArrayList<String>(); if (cursor.moveToFirst()) { while ( !cursor.isAfterLast() ) { if(cursor.getInt(cursor.getColumnIndex("list"))==intValue) { arrTblNames.add(cursor.getString(cursor.getColumnIndex("name"))); } cursor.moveToNext(); } String[] from = {DatabaseProductHelper.PRODUCT_NAME, DatabaseProductHelper.PRODUCT_COUNT, DatabaseProductHelper.PRODUCT_TYPE, DatabaseProductHelper.PRODUCT_COMPLETE}; int[] to = {R.id.ColMemberID, R.id.ColName, R.id.count_tv, R.id.chb_products}; adapter = new InteractiveArrayAdapter(ListBuilder.this, R.layout.row, cursorc, from, to ); //lv_products.setAdapter(adapter); } if(!arrTblNames.isEmpty()){ empty_bd_layout.setAlpha(0); lv_products.setAdapter(adapter); } else{ empty_bd_layout.setAlpha(255); } }

And the adapter itself

 public class InteractiveArrayAdapter extends SimpleCursorAdapter { private int layout; private boolean checked[]; public InteractiveArrayAdapter(Context _context, int _layout, Cursor _cursor, String[] _from, int[] _to) { super(_context, _layout, _cursor, _from, _to); layout = _layout; int counts = _cursor.getCount(); checked = new boolean[counts]; for (int i = 0; i < counts; i++){ int checkMarker = _cursor.getInt(_cursor.getColumnIndex("complete")); checked[i] = checkMarker == 1; } } @Override public void bindView(View view, Context _context, Cursor _cursor) { String prod_name = _cursor.getString(_cursor.getColumnIndex(DatabaseProductHelper.PRODUCT_NAME)); String prod_count = _cursor.getString(_cursor.getColumnIndex(DatabaseProductHelper.PRODUCT_COUNT)); String prod_type = _cursor.getString(_cursor.getColumnIndex(DatabaseProductHelper.PRODUCT_TYPE)); // int prod_complete = _cursor.getInt(_cursor.getColumnIndex(DatabaseProductHelper.PRODUCT_COMPLETE)); TextView name_prod_tv = (TextView)view.findViewById(R.id.ColMemberID); TextView count_prod_tv = (TextView)view.findViewById(R.id.ColName); TextView type_prod_tv = (TextView)view.findViewById(R.id.count_tv); CheckBox chb = (CheckBox)view.findViewById(R.id.chb_products); chb.setFocusable(false); chb.setClickable(false); name_prod_tv.setText(prod_name); count_prod_tv.setText(prod_count); type_prod_tv.setText(prod_type); chb.setChecked(checked[_cursor.getPosition()]); } @Override public View newView(Context _context, Cursor _cursor, ViewGroup _parent) { LayoutInflater inflater = (LayoutInflater)_context.getSystemService(_context.LAYOUT_INFLATER_SERVICE); View view = inflater.inflate(layout, _parent, false); return view; } public void setChecked(int position){ // инвертируем значение при обработке клика этим методом checked[position]=!checked[position]; } }

LogCat FATAL EXCEPTION: main 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime Process: ru.diskrim.listbuy, PID: 1468 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime java.lang.RuntimeException: Unable to start activity ComponentInfo {ru.diskrim.listbuy / ru.diskrim.listbuy.ListBuilder}: android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 4 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at android.app. ActivityThread.performLaunchActivity (ActivityThread.java:2325) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at android.app.ActivityThread.handleLaunchActivity (ActivityThread.java:2387) 05-09 07: 18: 292929 1468 1468 E AndroidRuntime at android.app.ActivityThread.access $ 800 (ActivityThread.java:151) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at android.app.ActivityThread $ H.handleMessage (ActivityThread.java:1303) 05-09 07:18 : 29.529 1468 1468 E AndroidRuntime at android.os.Handler.dispatchMessage (Handler.java:102) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at androi d.os.Looper.loop (Looper.java:135) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at android.app.ActivityThread.main (ActivityThread.java 12.2525) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at java.lang.reflect.Method.invoke (Native Method) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at java.lang.reflect.Method.invoke (Method.javaUE72) 05-09 07 : 18: 29.529 1468 1468 E AndroidRuntime at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run (ZygoteInit.java:902) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at com.android.internal.os. ZygoteInit.main (ZygoteInit.java:697) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at de.robv.android.xposed.XposedBridge.main (XposedBridge.java:117) 05-09 07: 18: 2929 1468 1468 E AndroidRuntime Caused by: android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 4 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at android.database.AbstractCursor.checkPosition (AbstractCursor.java T26) 05 -09 07: 18: 29.529 1468 1468 E AndroidRuntime at android.database.AbstractWindowedCursor.checkPosition (AbstractWindowedCursor.java:136) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at android.database.AbstractWindowedCursor.getInt (AbstractWindowedCursor.java:68) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at en.diskrim.listbuy.ListBuilder $ InteractiveArrayAdapter. (ListBuilder.java:245) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at en.diskrim.listbuy.ListBuilder.getProductList (ListBuilder.jr 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at en.diskrim.listbuy.ListBuilder.onCreate (ListBuilder.java:184) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at android.app.Activity.performCreate ( Activity.java:6033) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at android.app.Instrumentation.callActivityOnCreate (Instrumentation.java:1106) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime at android.app. ActivityThread.performLaunchActivity (ActivityThread.java:2278) 05-09 07: 18: 29.529 1468 1468 E AndroidRuntime ... 11 more

recommend yet to learn the parameters of the method of query() / request should look something like this: final Cursor cursorc = mSqLiteDatabase.query("products", new String[] {DatabaseProductHelper.PRODUCT_ID, DatabaseProductHelper.PRODUCT_NAME, DatabaseProductHelper.PRODUCT_COUNT, DatabaseProductHelper.PRODUCT_LIST, DatabaseProductHelper.PRODUCT_TYPE, DatabaseProductHelper.PRODUCT_COMPLETE}, "list = ?", new String[] {""+ intValue], null, null, null) ;

Community spirit ♦ one · Accepted Answer · 2016-05-08T04:41:50

The solution is not much different from this answer , with the difference that you need to handle clicks from the activation, and not the listener in the adapter.

Since we cannot change the values in the cursor, but only read them from there, in order to memorize the current state of checkboxes, we need to create a local storage.

In the adapter you need to transfer the data that should be displayed in the widget, in your case it is a cursor with a selection from the database. Auxiliary array of Boolean values is not required to be transferred anywhere; it is created inside the adapter.

An example implementation might look like this:

 private void getProductList() { // Если требуется только имя, следует и запрашивать из БД только //колонку с именем, а не все в кучу // Если требуется только записи с каким то условием, то их и надо запрашивать, // а не все в подряд, а потом выбирать нужные каким то циклом // так же эти данные включены и в курсор для адаптера и нет нужды // получать то же самое дважды // final Cursor cursor = mSqLiteDatabase.query("products", new String[] {DatabaseProductHelper.PRODUCT_ID, DatabaseProductHelper.PRODUCT_NAME,"list = ?", new String[] {""+ intValue}, null, null, null) ; //то же самое, только нужные в адаптере колонки final Cursor cursorc = mSqLiteDatabase.query("products", new String[] {DatabaseProductHelper.PRODUCT_ID,DatabaseProductHelper.PRODUCT_NAME, DatabaseProductHelper.PRODUCT_COUNT, DatabaseProductHelper.PRODUCT_TYPE, DatabaseProductHelper.PRODUCT_COMPLETE}, "list = ?", new String[] {""+ intValue}, null, null, null); final ArrayList<String> arrTblNames = new ArrayList<String>(); // копирование данных из курсора в массив сильно упрощается, // так как у нас только нужные данные while ( cursorc.moveToNext() ) { arrTblNames.add(cursorc.getString(cursorc.getColumnIndex("name"))); } String[] from = {DatabaseProductHelper.PRODUCT_NAME, DatabaseProductHelper.PRODUCT_COUNT, DatabaseProductHelper.PRODUCT_TYPE, DatabaseProductHelper.PRODUCT_COMPLETE}; int[] to = {R.id.ColMemberID, R.id.ColName, R.id.count_tv, R.id.chb_products}; adapter = new InteractiveArrayAdapter(ListBuilder.this, R.layout.row, cursorc, from, to ); //lv_products.setAdapter(adapter); } // у виджетов есть свойство Visiblity, которое управляет видимостью на // экране, зачем тут использовать прозрачность ? // я бы поменял всю логику вообще, исходя из условия ниже, // зачем получаnь и формировать данные, если они могут не понадобится if(!arrTblNames.isEmpty()){ empty_bd_layout.setAlpha(0); lv_products.setAdapter(adapter); } else{ empty_bd_layout.setAlpha(255); } }

adapter:

 public class InteractiveArrayAdapter extends SimpleCursorAdapter { private int layout; private boolean checked[]; public InteractiveArrayAdapter(Context _context, int _layout, Cursor _cursor, String[] _from, int[] _to) { super(_context, _layout, _cursor, _from, _to); layout = _layout; // инициализируем вспомогательный массив начальными отметками чекбоксов из курсора checked = new boolean[_cursor.getCount()]; int i = 0; while ( _cursor.moveToNext() ) { int checkMarker = _cursor.getInt(_cursor.getColumnIndex(DatabaseProductHelper.PRODUCT_COMPLETE)); checked[i] = (checkMarker == 1) ? true: false; i = i + 1; } // нужно вернуть указатель курсора в первоначальное положение // перед первой записью, для корректной работы адаптера _cursor.moveToPosition(-1); } @Override public void bindView(View view, Context _context, Cursor _cursor) { String prod_name = _cursor.getString(_cursor.getColumnIndex(DatabaseProductHelper.PRODUCT_NAME)); String prod_count = _cursor.getString(_cursor.getColumnIndex(DatabaseProductHelper.PRODUCT_COUNT)); String prod_type = _cursor.getString(_cursor.getColumnIndex(DatabaseProductHelper.PRODUCT_TYPE)); // эта строка здесь теперь по видимому не нужна, поскольку значения отметок // из курсора мы уже извлекли //int prod_complete = _cursor.getInt(_cursor.getColumnIndex(DatabaseProductHelper.PRODUCT_COMPLETE)); TextView name_prod_tv = (TextView)view.findViewById(R.id.ColMemberID); TextView count_prod_tv = (TextView)view.findViewById(R.id.ColName); TextView type_prod_tv = (TextView)view.findViewById(R.id.count_tv); CheckBox chb = (CheckBox)view.findViewById(R.id.chb_products); chb.setFocusable(false); chb.setClickable(false); name_prod_tv.setText(prod_name); count_prod_tv.setText(prod_count); type_prod_tv.setText(prod_type); // устанавливаем чекбоксы по вспомогательному массиву, а не по курсору // получаем текущую позицию курсора (и соответственно адаптера) через его метод chb.setChecked(checked[_cursor.getPosition()]); } @Override public View newView(Context _context, Cursor _cursor, ViewGroup _parent) { LayoutInflater inflater = (LayoutInflater)_context.getSystemService(_context.LAYOUT_INFLATER_SERVICE); View view = inflater.inflate(layout, _parent, false); return view; } // метод для фиксации изменений отметок чекбоксов из активити public void setChecked(int position){ // инвертируем значение при обработке клика этим методом checked[position] = !checked[position]; } }

As I recall, you record changes to the database by checkbox marks when processing a click in the list listener, so this action is not included in the adapter, but it must be present, otherwise the marks will be lost when leaving the list.

now I understand everything is average) that's just a mistake.
in LogCat-E android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 2 ... swears at the line int checkMarker = _cursor.getInt (_cursor.getColumnIndex ("complete"));
PS when instead of the hard column name there was a reference to a variable from the wrapper class, it produced the same error
The getColumnIndex() method returns -1, and for arrays indexes are possible starting from zero.
The reason itself is that there is no column in the cursor to which you refer, in this case -1 is returned, and not the column number.
Most likely the name of the column in the request is incorrectly written.
and yet, the getColumnIndex() method cannot find a column with the specified name.
if the name is spelled correctly, including capital letters, possible spaces at the beginning / end, or other confusions with symbols, then the received cursor does not have this column at all, see the query that you send to get the cursor.
Try to put just the number of this column (counting starts from zero).
For example, if this column is the fourth in the table, then: int checkMarker = _cursor.getInt(3);
However, the very fact that the cursor size in the spectra is indicated in three columns (with a size of 2 - columns 0,1,2) suggests the absence of the cursor you need in the received cursor, see your request and the inclusion of this column in the sample.

SimpleCursorAdapter + ListView: Checkboxes are lost when scrolling

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