新建的项目，一定要记得添加读写文件的权限啊，不然没有效果的，你不加权限，没有效果请不要找我
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
（1）我们首先需要创建assets文件夹，如图所示，在project状态下，鼠标选中main文件夹，右键单击，然后依次选择我们的内容，最后点击确定，assets就创建好了
然后我们在assets文件夹下面新建一个文件夹叫folder，把我们需要复制的文件放到此文件夹下面，我们放了三个不同的文件，如图所示：
（2）复制assets文件到内部存储中
package com.android.example.assets;
import android.content.Context;
import android.util.Log;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class Utils{
public static void doCopy(Context context, String assetsPath, String desPath) throws IOException {
String[] srcFiles = context.getAssets().list(assetsPath);//for directory
for (String srcFileName : srcFiles) {
String outFileName = desPath + File.separator + srcFileName;
String inFileName = assetsPath + File.separator + srcFileName;
if (assetsPath.equals("")) {// for first time
inFileName = srcFileName;
}
Log.e("tag","========= assets: "+ assetsPath+" filename: "+srcFileName +" infile: "+inFileName+" outFile: "+outFileName);
try {
InputStream inputStream = context.getAssets().open(inFileName);
copyAndClose(inputStream, new FileOutputStream(outFileName));
} catch (IOException e) {//if directory fails exception
e.printStackTrace();
new File(outFileName).mkdir();
doCopy(context,inFileName, outFileName);
}
}
}
private static void closeQuietly(OutputStream out){
try{
if(out != null) out.close();;
}catch (IOException ex){
ex.printStackTrace();
}
}
private static void closeQuietly(InputStream is){
try{
if(is != null){
is.close();
}
}catch (IOException ex){
ex.printStackTrace();
}
}
private static void copyAndClose(InputStream is, OutputStream out) throws IOException{
copy(is,out);
closeQuietly(is);
closeQuietly(out);
}
private static void copy(InputStream is, OutputStream out) throws IOException{
byte[] buffer = new byte[1024];
int n = 0;
while(-1 != (n = is.read(buffer))){
out.write(buffer,0,n);
}
}
}
这个时候，请你们打开手机的内部存储，文件在Android/data/项目包名/files/ 里面就是啦，反正我的手机是有的，你们试一下，按照我的步骤来，肯定也是有的，到这里我们的复制就成功了
（3）计算文件大小的类
package com.example.administrator.testz;
import android.util.Log;
import java.io.File;
import java.io.FileInputStream;
import java.text.DecimalFormat;
/**
* @CreateBy HaiyuKing
* @Used android 获取文件夹或文件的大小 以B、KB、MB、GB 为单位
* @参考资料 http://blog.csdn.net/jiaruihua_blog/article/details/13622939
*/
public class FileSizeUtil {
public static final int SIZETYPE_B = 1;//获取文件大小单位为B的double值
public static final int SIZETYPE_KB = 2;//获取文件大小单位为KB的double值
public static final int SIZETYPE_MB = 3;//获取文件大小单位为MB的double值
public static final int SIZETYPE_GB = 4;//获取文件大小单位为GB的double值
/**
* 获取指定文件或指定文件夹的的指定单位的大小
* @param filePath 文件路径
* @param sizeType 获取大小的类型1为B、2为KB、3为MB、4为GB
* @return double值的大小
*/
public static double getFolderOrFileSize(String filePath,int sizeType){
File file=new File(filePath);
long blockSize=0;
try {
if(file.isDirectory()){
blockSize = getFolderSize(file);
}else{
blockSize = getFileSize(file);
}
} catch (Exception e) {
e.printStackTrace();
Log.e("获取文件大小","获取失败!");
}
return FormetFileSize(blockSize, sizeType);
}
public static double getsizeFolderOrFileSize(File file,int sizeType){
long blockSize=0;
try {
if(file.isDirectory()){
blockSize = getFolderSize(file);
}else{
blockSize = getFileSize(file);
}
} catch (Exception e) {
e.printStackTrace();
Log.e("获取文件大小","获取失败!");
}
return FormetFileSize(blockSize, sizeType);
}
/**
* 调用此方法自动计算指定文件或指定文件夹的大小
* @param filePath 文件路径
* @return 计算好的带B、KB、MB、GB的字符串
*/
public static String getAutoFolderOrFileSize(String filePath){
File file=new File(filePath);
long blockSize=0;
try {
if(file.isDirectory()){
blockSize = getFolderSize(file);
}else{
blockSize = getFileSize(file);
}
} catch (Exception e) {
e.printStackTrace();
Log.e("获取文件大小","获取失败!");
}
return FormetFileSize(blockSize);
}
/**
* 获取指定文件的大小
* @param file
* @return
* @throws Exception
*/
private static long getFileSize(File file) throws Exception
{
long size = 0;
if (file.exists()){
FileInputStream fis = null;
fis = new FileInputStream(file);
size = fis.available();
fis.close();
}
else{
file.createNewFile();
Log.e("获取文件大小","文件不存在!");
}
return size;
}
/**
* 获取指定文件夹的大小
* @param file
* @return
* @throws Exception
*/
private static long getFolderSize(File file) throws Exception
{
long size = 0;
File flist[] = file.listFiles();
for (int i = 0; i < flist.length; i++){
if (flist[i].isDirectory()){
size = size + getFolderSize(flist[i]);
}
else{
size =size + getFileSize(flist[i]);
}
}
return size;
}
/**
* 转换文件大小
* @param fileSize
* @return
*/
private static String FormetFileSize(long fileSize)
{
DecimalFormat df = new DecimalFormat("#.00");
String fileSizeString = "";
String wrongSize="0B";
if(fileSize==0){
return wrongSize;
}
if (fileSize < 1024){
fileSizeString = df.format((double) fileSize) + "B";
}
else if (fileSize < 1048576){
fileSizeString = df.format((double) fileSize / 1024) + "KB";
}
else if (fileSize < 1073741824){
fileSizeString = df.format((double) fileSize / 1048576) + "MB";
}
else{
fileSizeString = df.format((double) fileSize / 1073741824) + "GB";
}
return fileSizeString;
}
/**
* 转换文件大小,指定转换的类型
* @param fileSize
* @param sizeType
* @return
*/
private static double FormetFileSize(long fileSize,int sizeType)
{
DecimalFormat df = new DecimalFormat("#.00");
double fileSizeLong = 0;
switch (sizeType) {
case SIZETYPE_B:
fileSizeLong=Double.valueOf(df.format((double) fileSize));
break;
case SIZETYPE_KB:
fileSizeLong=Double.valueOf(df.format((double) fileSize / 1024));
break;
case SIZETYPE_MB:
fileSizeLong=Double.valueOf(df.format((double) fileSize / 1048576));
break;
case SIZETYPE_GB:
fileSizeLong=Double.valueOf(df.format((double) fileSize / 1073741824));
break;
default:
break;
}
return fileSizeLong;
}
}
（4）在主文件中调用，那个路径写死了 是我的手机的路径 你们可能需要改一下才可以使用，写完以后运行吧，有一个重要的log日志，是关于打印文件路径的，这个路径就是复制到手机内存的路径啦
package com.example.administrator.testz;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.io.File;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
private Button btn_txt,button;
private EditText et;
private TextView txt;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn_txt = (Button)findViewById(R.id.btn_txt);
button= (Button)findViewById(R.id.button);
et = (EditText)findViewById(R.id.et);
txt = (TextView) findViewById(R.id.txt);
/*
/storage/emulated/0/Android/data/com.example.administrator.testz/files/aspcone.jsah
/storage/emulated/0/Android/data/com.example.administrator.testz/files/like.png
/storage/emulated/0/Android/data/com.example.administrator.testz/files/test.txt
*/
et.setText("/storage/emulated/0/Android/data/com.example.administrator.testz/files/aspcone.jsah");
btn_txt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
try {
doCopy();
} catch (IOException e) {
e.printStackTrace();
}
}
});
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String pathname = et.getText().toString();
double fileSizeKB = FileSizeUtil.getFolderOrFileSize(pathname,FileSizeUtil.SIZETYPE_KB);
String fileSize = FileSizeUtil.getAutoFolderOrFileSize(pathname);
txt.setText("fileSizeKB=" + fileSizeKB + "\n" +
"fileSize=" + fileSize);
}
});
}
private void doCopy() throws IOException{
File externalDir = this.getExternalFilesDir(null);
Utils.doCopy(this,"folder",externalDir.getPath());
}
}
最后贴上我们的运行效果：
大致就是这么个效果啦，如果需要源码的同学，请关注我，进入我的csdn资源，我已经把源码上传到csdn了