Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Try looping using an <code>Iterator</code>, since per Oracle <code>Iterator.remove()</code> is the only safe way to remove an item from a <code>Collection</code> (including a <code>Stack</code>) during iteration.</p> <p>From <a href="http://docs.oracle.com/javase/tutorial/collections/interfaces/collection.html" rel="nofollow">http://docs.oracle.com/javase/tutorial/collections/interfaces/collection.html</a></p> <blockquote> <p>Note that Iterator.remove is the only safe way to modify a collection during iteration; the behavior is unspecified if the underlying collection is modified in any other way while the iteration is in progress.</p> </blockquote> <p>So something like the following should work:</p> <pre><code>Stack&lt;Particle&gt; particles = new Stack&lt;Particle&gt;(); ... // Add a bunch of particles Iterator&lt;Particle&gt; iter = particles.iterator(); while (iter.hasNext()) { Particle p = iter.next(); if (!p.isAlive()) { iter.remove(); } } </code></pre> <p>I've used this approach in a real Android app (<a href="https://play.google.com/store/apps/details?id=com.joulespersecond.seattlebusbot" rel="nofollow">OneBusAway Android</a> - see code <a href="https://github.com/OneBusAway/onebusaway-android/blob/35fbc9549dc5bff8ff1c0c0bc71274b4d6d13c20/src/com/joulespersecond/seattlebusbot/RegionsFragment.java#L124" rel="nofollow">here</a>), and it worked for me. Note that in the code for this app I also included a try/catch block in case the platform throws an exception, and in this case just iterate through a copy of the collection and then remove the item from the original collection.</p> <p>For you, this would look like:</p> <pre><code>try { ... // above code using iterator.remove } catch(UnsupportedOperationException e) { Log.w(TAG, "Problem removing from stack using iterator: " + e); // The platform apparently didn't like the efficient way to do this, so we'll just // loop through a copy and remove what we don't want from the original ArrayList&lt;Particle&gt; copy = new ArrayList&lt;Particle&gt;(particles); for (Particle p : copy) { if (!p.isAlive()) { particles.remove(p); } } } </code></pre> <p>This way you get the more efficient approach if the platform supports it, and if not you still have a backup.</p>
    singulars
    1. This table or related slice is empty.
    1. PORemoving an item from a stack, whilst iterating over it, in android
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USSean Barbeau
    1. USSean Barbeau
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PORemoving an item from a stack, whilst iterating over it, in android
      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. VTUpMod
    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. VTAcceptedByOriginator
    1. COthis is what i tried after i found my stack method didn't work. but it kept trying to get another item when it had none despite we asking if it had next before getting next. either way i didn't user iterator.remove(); so i will certainly try this! i have to go to school but i will be back to see if this worked!
      singulars
      1. PO
      1. USMarcus Gosselin
    2. COThanks, let me know how it goes! I also just added a reference to where I've used this in a real app, along with some fallback code if the more efficient version doesn't work.
      singulars
      1. PO
      1. USSean Barbeau
    3. COi quite like the copying idea! one question about it though; When you create the copy, are the objects in the list copied, or are they just referenced with a different alias. ie, could i modify one in the copy and have the regular one and the copy be affectd?
      singulars
      1. PO
      1. USMarcus Gosselin
 

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