Java Iterators

//Iterate in Bundle

Bundle mBundle = data.getExtras();

for (String key : mBundle.keySet()) {
  Log.e(key, mBundle.get(key).toString());
}

//Iterate in SharedPreferences
SharedPreferences myShPref = getSharedPreferences("mySharedPreferences", Context.MODE_PRIVATE);

#1
Map<String, ?> allEntries = myShPref.getAll();
for (Map.Entry<String, ?> entry : allEntries.entrySet()) {
    Log.d("MAP values", entry.getKey() + ": " + entry.getValue().toString());
}

#2
Map<String, ?> map = myShPref.getAll();
if (map.size() > 0) {
   Set<String> playIds = map.keySet();
}

implode(playIds)

public static String implode(Collection<String> data) {
    Iterator<String> it = data.iterator();
    if (! it.hasNext())
        return "";

    StringBuilder sb = new StringBuilder();
    sb.append("(\"");
    for (;;) {
        String e = it.next();
        sb.append(e);
        if (! it.hasNext())
            return sb.append("\")").toString();
        sb.append('"').append(',').append('"');
    }
}