android判断版本更新算法

/**
 * 判断版本更新
 * @param version1 服务器应用版本
 * @param version2 应用本身版本
 * @return 0=>版本相同，1=>版本需要更新，-1版本不需要更新
 */
private int compareVersion(String version1, String version2) {
    if (version1.equals(version2)) {
        return 0;
    }
    String[] version1Array = version1.split("\.");
    String[] version2Array = version2.split("\.");
    int minLen = Math.min(version1Array.length, version2Array.length);
    int index = 0;
    int diff = 0;
    while (index < minLen
            && (diff = Integer.parseInt(version1Array[index])
                    - Integer.parseInt(version2Array[index])) == 0) {
        index++;
    }
    if (diff == 0) {
        for (int i = index; i < version1Array.length; i++) {
            if (Integer.parseInt(version1Array[i]) > 0) {
                return 1;
            }
        }
        for (int i = index; i < version2Array.length; i++) {
            if (Integer.parseInt(version2Array[i]) > 0) {
                return -1;
            }
        }
        return 0;
    } else {
        return diff > 0 ? 1 : -1;
    }
}