Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>After API 11 the <code>SharedPreferences Editor</code> accept <code>Sets</code>. You could convert your List into a <code>HashSet</code> or something similar and store it like that. When your read it back, convert it into an <code>ArrayList</code>, sort it if needed and you're good to go.</p> <pre><code>//Retrieve the values Set&lt;String&gt; set = myScores.getStringSet("key", null); //Set the values Set&lt;String&gt; set = new HashSet&lt;String&gt;(); set.addAll(listOfExistingScores); scoreEditor.putStringSet("key", set); scoreEditor.commit(); </code></pre> <hr> <p>You can also serialize your <code>ArrayList</code> and then save/read it to/from <code>SharedPreferences</code>. Below is the solution:</p> <p><strong>EDIT:</strong><br> Ok, below is the solution to save <code>ArrayList</code> as serialized object to <code>SharedPreferences</code> and then read it from SharedPreferences.</p> <p>Because API supports only storing and retrieving of strings to/from SharedPreferences (after API 11, its simpler), we have to serialize and de-serialize the ArrayList object which has the list of tasks into string.</p> <p>In the <code>addTask()</code> method of the TaskManagerApplication class, we have to get the instance of the shared preference and then store the serialized ArrayList using the <code>putString()</code> method:</p> <pre><code>public void addTask(Task t) { if (null == currentTasks) { currentTasks = new ArrayList&lt;task&gt;(); } currentTasks.add(t); // save the task list to preference SharedPreferences prefs = getSharedPreferences(SHARED_PREFS_FILE, Context.MODE_PRIVATE); Editor editor = prefs.edit(); try { editor.putString(TASKS, ObjectSerializer.serialize(currentTasks)); } catch (IOException e) { e.printStackTrace(); } editor.commit(); } </code></pre> <p>Similarly we have to retrieve the list of tasks from the preference in the <code>onCreate()</code> method:</p> <pre><code>public void onCreate() { super.onCreate(); if (null == currentTasks) { currentTasks = new ArrayList&lt;task&gt;(); } // load tasks from preference SharedPreferences prefs = getSharedPreferences(SHARED_PREFS_FILE, Context.MODE_PRIVATE); try { currentTasks = (ArrayList&lt;task&gt;) ObjectSerializer.deserialize(prefs.getString(TASKS, ObjectSerializer.serialize(new ArrayList&lt;task&gt;()))); } catch (IOException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } } </code></pre> <p>You can get <code>ObjectSerializer</code> class from Apache Pig project <a href="https://github.com/apache/pig/blob/89c2e8e76c68d0d0abe6a36b4e08ddc56979796f/src/org/apache/pig/impl/util/ObjectSerializer.java" rel="noreferrer">ObjectSerializer.java</a></p>
    singulars
    1. This table or related slice is empty.
    1. POSave ArrayList to SharedPreferences
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USevilone
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POSave ArrayList to SharedPreferences
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COKeep in mind that `putStringSet` was added at API 11. Most current programmers target at lease API 8 (Froyo).
      singulars
      1. PO
      1. USCristian
    2. COI like the idea of this method because it seems to be the cleanest, but the array I am looking to store is a custom class object that contains strings, doubles, and booleans. How do I go about adding all 3 of these types to a set? Do I have to set every individual object to their own array and then add them individually to separate sets before I store, or is there a simpler way?
      singulars
      1. PO
      1. USryandlf
    3. COLike Christian said, this feature was added at API 11 and I don't recommend you to use this, because API 11 is used by very small group of devices. Look for my EDIT section - there's a suggestion for an earlier API versions.
      singulars
      1. PO
      1. USevilone
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload