NullPointer.Exception PopupWindow.getMaxAvailableHeight using ListPopupWindow-Collection of common programming errors

I’m trying to use a PopupWindow with an adapter but this exception occurs. I tried to search for something that solve this problem but I didn’t found anything.

Here is the Exception

07-18 10:58:27.600: D/dalvikvm(15218): GC_FOR_ALLOC freed 56K, 3% free 6409K/6595K, paused 40ms
07-18 10:58:27.600: I/dalvikvm-heap(15218): Grow heap (frag case) to 6.804MB for 513744-byte allocation
07-18 10:58:27.669: D/dalvikvm(15218): GC_FOR_ALLOC freed 8K, 3% free 6902K/7111K, paused 41ms
07-18 10:58:27.749: D/dalvikvm(15218): GC_CONCURRENT freed