这个可以直接在我们获取总体容量时使用。

上面把系统是怎么做的大概搞清楚，下面我们来实现我们的需求：

3、下面时我实现的工具类，希望对你有用：

package com.linuxidc.jerome;

import java.io.File;
import java.util.ArrayList;

import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Environment;
import android.os.StatFs;
import android.provider.MediaStore;

public class MemoryUtil {
?Context mContext;

?public MemoryUtil(Context context) {
? mContext = context;
?}

?/**
? * 获得SD卡总大小
? *
? * @return
? */
?public long getSDTotalSize() {
? File path = Environment.getExternalStorageDirectory();
? StatFs stat = new StatFs(path.getPath());
? long blockSize = stat.getBlockSize();
? long totalBlocks = stat.getBlockCount();
? return blockSize * totalBlocks;
?}

?/**
? * 获得sd卡剩余容量，即可用大小
? *
? * @return
? */
?public long getSDAvailableSize() {
? File path = Environment.getExternalStorageDirectory();
? StatFs stat = new StatFs(path.getPath());
? long blockSize = stat.getBlockSize();
? long availableBlocks = stat.getAvailableBlocks();
? return blockSize * availableBlocks;
?}

?/**
? * 获得机身内存总大小
? *
? * @return
? */
?public long getRomTotalSize() {
? File path = Environment.getDataDirectory();
? StatFs stat = new StatFs(path.getPath());
? long blockSize = stat.getBlockSize();
? long totalBlocks = stat.getBlockCount();
? return blockSize * totalBlocks;
?}

?/**
? * 获得机身可用内存
? *
? * @return
? */
?public long getRomAvailableSize() {
? File path = Environment.getDataDirectory();
? StatFs stat = new StatFs(path.getPath());
? long blockSize = stat.getBlockSize();
? long availableBlocks = stat.getAvailableBlocks();
? return blockSize * availableBlocks;
?}

?/**
? * 外部存储中所有音频文件所占内存
? *
? * @return
? */
?public long getAudioTotalSize() {
? ArrayList resultList = queryAllMediaList(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI);
? long size = 0L;
? for (MemoryInfo cInfo : resultList) {
? ?File file = new File(cInfo.getFilePath());
? ?if(null!=file &&file.exists()){
? ? size += cInfo.getFileSize();
? ?}
? }
? return size;
?}

?/**
? * 外部存储中除音频、视频、图片之前其他文件所占内存
? *
? * @return
? */
?public long getOtherTotalSize() {
? long size = getSDTotalSize() - getSDAvailableSize()
? ? - getPictureTotalSize() - getVideoTotalSize()
? ? - getAudioTotalSize();
? if (size < 0L) {
? ?size = 0L;
? }
? return size;
?}

?/**
? * 外部存储中所有图片文件所占内存
? *
? * @return
? */
?public long getPictureTotalSize() {
? ArrayList resultList = queryAllMediaList(MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
? long size = 0L;
? for (MemoryInfo cInfo : resultList) {
? ?File file = new File(cInfo.getFilePath());
? ?if(null!=file &&file.exists()){
? ? size += cInfo.getFileSize();
? ?}
? }
? return size;
?}

?/**
? * 外部存储中所有视频文件所占内存
? *
? * @return
? */
?public long getVideoTotalSize() {
? ArrayList resultList = queryAllMediaList(MediaStore.Video.Media.EXTERNAL_CONTENT_URI);
? long size = 0L;
? for (MemoryInfo cInfo : resultList) {
? ?File file = new File(cInfo.getFilePath());
? ?if(null!=file &&file.exists()){
? ? size += cInfo.getFileSize();
? ?}
? }
? return size;
?}

?public ArrayList queryAllMediaList(Uri uri) {
? //我们只需要两个字段：大小、文件路径
? Cursor cursor = mContext.getContentResolver().query(
? ? uri,new String[] { MediaStore.Audio.Media.SIZE,
? ? ? MediaStore.Audio.Media.DATA }, null, null, null);