Android应用性能优化之使用SparseArray替代HashMap

转自http://liuzhichao.com/p/832.html

用SparseArray<E>来替代HashMap<Integer,
E>

核心折半查找函数（binarySearch）

private static int binarySearch(int[] a, int start, int len, int key) {
int high = start + len, low = start - 1, guess;

while (high - low > 1) {
guess = (high + low) / 2;

if (a[guess] < key)
low = guess;
else
high = guess;
}

if (high == start + len)
return ~(start + len);
else if (a[high] == key)
return high;
else
return ~high;
}

相应的也有SparseBooleanArray，用来取代HashMap<Integer, Boolean>，SparseIntArray用来取代HashMap<Integer,
Integer>，大家有兴趣的可以研究。