Affected devices:
I have only seen it occur on a Samsung Galaxy S2 but I’m guessing it probably happens on any 2.x Samsung device running TouchWiz (it doesn’t happen on the Nexus S)

Steps to reproduce:
Create an activity with an ExpandableListView and set the childDivider property of the ExpandableListView to any colour, say red for ease of viewing

<ExpandableListView android:id="@+id/pageBundles"
                        android:layout_width="fill_parent"
                        android:layout_height="fill_parent"
                        android:childDivider="@color/red"
                        android:cacheColorHint="@color/white"/>

Now if you scroll the list for a while, particularly if you sort of wiggle it up and down quickly and then let it go the list will be completely covered by a solid block of the colour specified in the childDivider property. This will remain for a few seconds and then disappear.

To fix this issue just remove the childDivider property setting

Given a mapping of digits to an array of characters, ie.
"1"={},
"2"={"A","B","C"},
"3"={"D","E","F"},
etc.

Print out all the string permutations a given input of digits maps to.
So for instance the string “23″ should return:
AD
AE
AF
BD
BE
BF
CD
CE
CF

Another way to think of this is a function that returns all the possible combinations of letters the digits could represent if they were keypresses on a standard phone keypad.

I did a pretty bad job at this when I was asked it, partly because it was quite late at night, and partly because it’s not the sort of thing you find yourself doing that often, but today I found myself with a little bit of spare time on my hands and thought I’d give it another go.

I chose to do it in Scala rather than in Java which I had used last time and of course this led to the solution being much more elegant and succinct. If fact this is exactly the sort of problem that demonstrates the value of functional programming.

import collection.immutable.{List, Map}
import java.lang.String

object PhoneNumbers extends App {
  val input = "1234"
  val data = Map(
    0 -> List("0"),
    1 -> List("1"),
    2 -> List("a", "b", "c"),
    3 -> List("d", "e", "f"),
    4 -> List("g", "h", "i"),
    5 -> List("j", "k", "l"),
    6 -> List("m", "n", "o"),
    7 -> List("p", "q", "r", "s"),
    8 -> List("t", "u", "v"),
    9 -> List("w", "x", "y", "z")
  )
  getCombinations(input.substring(0, 1), input.substring(1))
    .foreach(f => Console.println(f))

  def getCombinations(current: String, remaining: String): List[String] = {
    val vals = data(Integer.parseInt(current));
    if (remaining.length() == 0)
      return vals

    val restOfString = getCombinations(remaining.substring(0, 1), remaining.substring(1))

    vals
      .map(f => restOfString.map(f2 => f + f2))
      .flatten
  }
}

By changing the settings on the account though I got it to work pretty much instantaneously.

Settings:

Login ID: your email address
Password: your password

Under advanced settings:

Check ‘Encryption Required’ checkbox
Resource: Home
Server: talk.google.com
Port: 5223
Check ‘Use old SSL’ checkbox

    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putIntArray("ARTICLE_SCROLL_POSITION",
                new int[]{ mScrollView.getScrollX(), mScrollView.getScrollY()});
    }

Then restore the position in the onRestoreInstanceState method, note that we need to post a runnable to the ScrollView to get this to work:

    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        final int[] position = savedInstanceState.getIntArray("ARTICLE_SCROLL_POSITION");
        if(position != null)
            mScrollView.post(new Runnable() {
                public void run() {
                    mScrollView.scrollTo(position[0], position[1]);
                }
            });
    }

1. put about:config in the address bar and hit enter
2. scroll down to browser.backspace_action and double click it
3. set the value to 0

git checkout -b my_new_branch

Fortunately getting the app to fill the whole screen just required the following line after the <application> section in my AndroidManifest.xml:

<uses-sdk  android:targetSdkVersion="9"/>