解决：Collections.sort java.lang.IllegalArgumentException: Comparison method violates its general conta

解决：Collections.sort java.lang.IllegalArgumentException: Comparison method violates its general contact!

如果你有2个元素的时候是平等的，你会得到比较（甲，乙）= 1和比较（乙，一）= = 1，这是没有任何意义。

如果t0==t1，一定要return0；

Collections.sort(mImgs, new Comparator<String>() {

@Override
public int compare(String o1, String o2) {


  /* int cmp = o1.compareTo(o2);
   if (cmp == 0) {
      // avoid expensive operations.
      Long VolTot1 = Long.parseLong(o1);
      Long VolTot2 = Long.parseLong(o2);
      cmp = VolTot1.compareTo(VolTot2);
      return cmp;
   }*/


long t1 = new File(o1).lastModified();
long t2 = new File(o2).lastModified();
if ( t1> t2 ) {
return -1;
}else if (t1<t2) {
return 1;
}else{
return 0;

}
}
});