How to store HashMap <Integer, ArrayList <String> for SQLite?
I need to store the HashMap value on SQLite using Keyset and reuse it when the app is restarted using shared preference.
HashMap<Integer, ArrayList<String>> hashMap;
hashMap = new HashMap<>();
//Insert Value
hashMap.put(btn.getId(), listValue);
// Read a Value
Map.Entry<Integer, ArrayList<String>> entry = (Map.Entry<Integer, ArrayList<String>>) iteratorMap.next();
for (Integer ihashId :hashMap.keySet()) {
if( btnid == ihashId)
{
Set<Map.Entry<Integer, ArrayList<String>>> setMap = hashMap.entrySet();
Iterator<Map.Entry<Integer, ArrayList<String>>> iteratorMap = setMap.iterator();
while (iteratorMap.hasNext()) {
Map.Entry<Integer, ArrayList<String>> entry = (Map.Entry<Integer, ArrayList<String>>) iteratorMap.next();
ArrayList<String> values = entry.getValue();
if (btnId == entry.getKey()) {
getSetName.setText(values.get(0));
getSetAddress.setText(values.get(1));
getSetPin.setText(values.get(2));
getSetValue.setText(values.get(3));
}
}
}
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Original answer before question Edited: The
HashMap is already serializable, so you can store the HashMap directly in your sqlite database as a BLOB. Though you won't be able to read its contents until you serialize it.
EDIT:
You have to put long running operations inside an async task. If you want the variable reference to survive configuration changes, you should use the snippet and use setRetainInstance(true)
, although whether or not you keep your reference to the AsyncTask it is independent of the UI thread and will continue to work.
NOTE:
Always use a manual computed loop when using ArrayList as it has better performance.
As you can see from this comparison , using the array size for a loop with a set counter is much faster than for each loop:
private static List<Integer> list = new ArrayList<>();
for(int j = list.size(); j > size ; j--)
{
//do stuff
}
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