title: out of memory issue with volley's disk cache
body: <p>In my app for Android I'm using Volley for loading images in custom listview.</p>
  
  <p>when i refresh(delete all items and load tiems) listview many times,
  my app is killed with this message</p>
  
  <p>how can i fix it?</p>
  
  <blockquote>
    <p>04-26 13:08:01.038: E/dalvikvm-heap(18040): Out of memory on a 1684947261-byte allocation.
    04-26 13:08:01.038: I/dalvikvm(18040): "Thread-11094" prio=5 tid=299 RUNNABLE
    04-26 13:08:01.038: I/dalvikvm(18040):   | group="main" sCount=0 dsCount=0 obj=0x439ea8e8 self=0x7fb55250
    04-26 13:08:01.038: I/dalvikvm(18040):   | sysTid=18946 nice=10 sched=0/0 cgrp=apps/bg_non_interactive handle=2102160344
    04-26 13:08:01.038: I/dalvikvm(18040):   | state=R schedstat=( 109248225 27367764 57 ) utm=9 stm=1 core=2
    04-26 13:08:01.038: I/dalvikvm(18040):   at com.android.volley.toolbox.DiskBasedCache.streamToBytes(DiskBasedCache.java:~316)
    04-26 13:08:01.038: I/dalvikvm(18040):   at com.android.volley.toolbox.DiskBasedCache.readString(DiskBasedCache.java:526)
    04-26 13:08:01.038: I/dalvikvm(18040):   at com.android.volley.toolbox.DiskBasedCache.readStringStringMap(DiskBasedCache.java:549)
    04-26 13:08:01.038: I/dalvikvm(18040):   at com.android.volley.toolbox.DiskBasedCache$CacheHeader.readHeader(DiskBasedCache.java:392)
    04-26 13:08:01.038: I/dalvikvm(18040):   at com.android.volley.toolbox.DiskBasedCache.initialize(DiskBasedCache.java:155)
    04-26 13:08:01.038: I/dalvikvm(18040):   at com.android.volley.CacheDispatcher.run(CacheDispatcher.java:84)
    04-26 13:08:01.048: W/dalvikvm(18040): threadid=299: thread exiting with uncaught exception (group=0x41745da0)
    04-26 13:08:01.048: I/SpenGestureManager(847): setFocusWindow0
    04-26 13:08:01.048: D/PointerIcon(847): setHoveringSpenIconStyle1 pointerType: 10001iconType:1 flag:0
    04-26 13:08:01.048: D/PointerIcon(847): setHoveringSpenCustomIcon IconType is same.1
    04-26 13:08:01.048: E/AndroidRuntime(18040): FATAL EXCEPTION: Thread-11094
    04-26 13:08:01.048: E/AndroidRuntime(18040): Process: com.android.myapp, PID: 18040
    04-26 13:08:01.048: E/AndroidRuntime(18040): java.lang.OutOfMemoryError
    04-26 13:08:01.048: E/AndroidRuntime(18040):    at com.android.volley.toolbox.DiskBasedCache.streamToBytes(DiskBasedCache.java:316)
    04-26 13:08:01.048: E/AndroidRuntime(18040):    at com.android.volley.toolbox.DiskBasedCache.readString(DiskBasedCache.java:526)
    04-26 13:08:01.048: E/AndroidRuntime(18040):    at com.android.volley.toolbox.DiskBasedCache.readStringStringMap(DiskBasedCache.java:549)
    04-26 13:08:01.048: E/AndroidRuntime(18040):    at com.android.volley.toolbox.DiskBasedCache$CacheHeader.readHeader(DiskBasedCache.java:392)
    04-26 13:08:01.048: E/AndroidRuntime(18040):    at com.android.volley.toolbox.DiskBasedCache.initialize(DiskBasedCache.java:155)
    04-26 13:08:01.048: E/AndroidRuntime(18040):    at com.android.volley.CacheDispatcher.run(CacheDispatcher.java:84)
    04-26 13:08:01.058: W/ActivityManager(847):   Force finishing activity com.android.myapp/.feedlist.Feedlist</p>
  </blockquote>