排序

Android 文件浏览器中涉及到文件按照文件名称、文件大小、修改时间 ，记录其排序算法如下，方便日后简单修改参考使用：

/**
 * sort file
 *
 * @param fileList   // file list
 * @param sortMethod 「名称、大小、时间」
 * @param MA 「Context」
 * @return List<File>
 */
public static List<File> sortFile(List<File> fileList, final String sortMethod, final CommonActivity MA) {

    Collections.sort(fileList, new Comparator<File>() {
        @Override
        public int compare(File object1, File object2) {
            return compareFile(object1, object2, sortMethod, MA);
        }
    });

    return fileList;
}

/**
 * A local file, mount the directory to sort the files to achieve CNcomment:
 * 本地文件，挂载目录文件排序实现
 *
 * @param object1
 * @param object2
 * @param sortMethod
 * @param MA
 * @return
 */
public static int compareFile(File object1, File object2,
                              String sortMethod, CommonActivity MA) {
    mx = MA;
    if (sortMethod.equals(mx.getResources().getString(R.string.file_name))) {
        return compareByName(object1, object2);
    } else if (sortMethod.equals(mx.getResources().getString(
            R.string.file_size))) {
        int len = compareBySize(object1.length(), object2.length());
        // the same size ,sort by name
        if (len == 0) {
            return compareByName(object1, object2);
        } else {
            return compareBySize(object1.length(), object2.length());
        }
    } else if (sortMethod.equals(mx.getResources().getString(
            R.string.update_time))) {
        int len = compareByDate(object1.lastModified(),
                object2.lastModified());
        // the same data ,sort by name
        if (len == 0) {
            return compareByName(object1, object2);
        } else {
            return compareByDate(object1.lastModified(),
                    object2.lastModified());
        }
    }
    return 0;
}
/**
 * sort according to file name
 *
 * @param object1
 * @param object2
 * @return
 */
private static int compareByName(File object1, File object2) {
    String objectName1 = object1.getName().toLowerCase();
    String objectName2 = object2.getName().toLowerCase();
    int result = objectName1.compareTo(objectName2);
    if (result == 0) {
        return 0;
    } else if (result < 0) {
        return -1;
    } else {
        return 1;
    }
}

/**
 * sort according to file size
 *
 * @param object1
 * @param object2
 * @return
 */
private static int compareBySize(long object1, long object2) {
    long diff = object1 - object2;
    if (diff > 0) {

        return 1;
    } else if (diff == 0) {

        return 0;
    } else {

        return -1;
    }
}

/**
 * file sorted by date modified
 *
 * @param object1
 * @param object2
 * @return
 */
public static int compareByDate(long object1, long object2) {
    long diff = object1 - object2;
    if (diff > 0) {
        return 1;
    } else if (diff == 0) {
        return 0;
    } else {
        return -1;
    }
}