Android中一些数据存储函数的封装
本人博客原文
Android很多手机现在都有EMMC存储（一般是2G），一些手机并没有挂载在getExternalStorageDirectory()这个节点上（该节点用于挂载外部sdcard了）.而是挂载到"/mnt/emmc"节点上，另外一些手机把
EMMC存储直接
挂载到了
getExternalStorageDirectory()
这个节点上,而对于真正的外部sdcard挂载到了
"/mnt/sdcard2"
这个节点上。另外
/system/etc/vold.fstab文件中描述了SD card的挂载点，我们可以读取它来得到关于
SD card的挂载点信息
。
因此当我们存储一个文件时首先应该存在
getExternalStorageDirectory()
这个节点上，其次是
"/mnt/sdcard2"
这个节点上，再次是
"/mnt/emmc"，再次考虑
/system/etc/vold.fstab文件中的挂载点
，最后才是手机的内部存储(即“/data”区域）。
注意：对于
/system/etc/vold.fstab文件中的挂载点，很可能就是
getExternalStorageDirectory()
这个节点上，或是
"/mnt/sdcard2"
这个节点上，或是是
"/mnt/emmc"。但是其实做两次检查应该没有什么副作用，由于对于读取
/system/etc/vold.fstab文件来得到
描述SD card的挂载点这个事情似乎不是一个官方的做法；我就把它放在了更低的优先级
。
另外，在很多手机上，虽然我们使用Context的
openFileOutput(FILENAME,
Context.
MODE_WORLD_READABLE
)
的方式来创建文件，而且使用ls -l看到该文件对别的应用程序来说其实已经有读的权限，但是别的应用程序实际上还是无法读取这些。这时我们需要在创建该文件的应用程序中对 getFilesDir()
目录执行"chmod 705"的操作来解决该问题。
我特把这些操作进行封装，以便使用。
package
cn
.
edu
.
cdut
.
robin
;
import
java
.
io
.
File
;
import
java
.
io
.
IOException
;
import
android
.
content
.
Context
;
import
android
.
os
.
Environment
;
import
android
.
os
.
StatFs
;
import
android
.
text
.
TextUtils
;
public
class
AppUtil
{
static
Context
context
;
static
void
init
(
Context
cxt
)
{
context
=
cxt
;
}
/** get external Storage available space */
public
static
long
getExternaltStorageAvailableSpace
()
{
if
(!
Environment
.
getExternalStorageState
().
equals
(
Environment
.
MEDIA_MOUNTED
))
{
return
0
;
}
File
path
=
Environment
.
getExternalStorageDirectory
();
StatFs
statfs
=
new
StatFs
(
path
.
getPath
());
long
blockSize
=
statfs
.
getBlockSize
();
long
availableBlocks
=
statfs
.
getAvailableBlocks
();
return
blockSize
*
availableBlocks
;
}
/** get external Storage available space */
public
static
long
getExternaltStorageTotalSpace
()
{
File
path
=
Environment
.
getExternalStorageDirectory
();
StatFs
statfs
=
new
StatFs
(
path
.
getPath
());
long
blockSize
=
statfs
.
getBlockSize
();
long
totalBlocks
=
statfs
.
getBlockCount
();
return
blockSize
*
totalBlocks
;
}
/** get sdcard2 external Storage available space */
public
static
long
getSdcard2StorageAvailableSpace
()
{
if
(!
Environment
.
getExternalStorageState
().
equals
(
Environment
.
MEDIA_MOUNTED
))
{
return
0
;
}
String
path
=
getSdcard2StorageDirectory
();
File
file
=
new
File
(
path
);
if
(!
file
.
exists
())
return
0
;
StatFs
statfs
=
new
StatFs
(
path
);
long
blockSize
=
statfs
.
getBlockSize
();
long
availableBlocks
=
statfs
.
getAvailableBlocks
();
return
blockSize
*
availableBlocks
;
}
/** get sdcard2 external Storage total space */
public
static
long
getSdcard2StorageTotalSpace
()
{
String
path
=
getSdcard2StorageDirectory
();
File
file
=
new
File
(
path
);
if
(!
file
.
exists
())
return
0
;
StatFs
statfs
=
new
StatFs
(
path
);
long
blockSize
=
statfs
.
getBlockSize
();
long
totalBlocks
=
statfs
.
getAvailableBlocks
();
return
blockSize
*
totalBlocks
;
}
/** get EMMC internal Storage available space */
public
static
long
getEmmcStorageAvailableSpace
()
{
String
path
=
getEmmcStorageDirectory
();
File
file
=
new
File
(
path
);
if
(!
file
.
exists
())
return
0
;
StatFs
statfs
=
new
StatFs
(
path
);
long
blockSize
=
statfs
.
getBlockSize
();
long
availableBlocks
=
statfs
.
getAvailableBlocks
();
return
blockSize
*
availableBlocks
;
}
/** get EMMC internal Storage available space */
public
static
long
getEmmcStorageTotalSpace
()
{
String
path
=
getEmmcStorageDirectory
();
File
file
=
new
File
(
path
);
if
(!
file
.
exists
())
return
0
;
StatFs
statfs
=
new
StatFs
(
path
);
long
blockSize
=
statfs
.
getBlockSize
();
long
totalBlocks
=
statfs
.
getBlockCount
();
return
blockSize
*
totalBlocks
;
}
static
FstabReader
fsReader
=
null
;
/** get other external Storage available space*/
public
static
long
getOtherExternaltStorageAvailableSpace
()
{
if
(!
Environment
.
getExternalStorageState
().
equals
(
Environment
.
MEDIA_MOUNTED
))
{
return
0
;
}
if
(
otherExternalStorageState
==
kOtherExternalStorageStateUnable
)
return
0
;
if
(
otherExternalStorageDirectory
==
null
)
{
getOtherExternalStorageDirectory
();
}
if
(
otherExternalStorageDirectory
==
null
)
return
0
;
StatFs
statfs
=
new
StatFs
(
otherExternalStorageDirectory
);
long
blockSize
=
statfs
.
getBlockSize
();
long
availableBlocks
=
statfs
.
getAvailableBlocks
();
return
blockSize
*
availableBlocks
;
}
private
static
String
otherExternalStorageDirectory
=
null
;
private
static
int
kOtherExternalStorageStateUnknow
=-
1
;
private
static
int
kOtherExternalStorageStateUnable
=
0
;
private
static
int
kOtherExternalStorageStateIdle
=
1
;
private
static
int
otherExternalStorageState
=
kOtherExternalStorageStateUnknow
;
public
static
String
getOtherExternalStorageDirectory
()
{
if
(
otherExternalStorageState
==
kOtherExternalStorageStateUnable
)
return
null
;
if
(
otherExternalStorageState
==
kOtherExternalStorageStateUnknow
)
{
FstabReader
fsReader
=
new
FstabReader
();
if
(
fsReader
.
size
()<=
0
)
{
otherExternalStorageState
=
kOtherExternalStorageStateUnable
;
return
null
;
}
List
<
StorageInfo
>
storages
=
fsReader
.
getStorages
();
/*对于可用空间小于100M的挂载节点忽略掉*/
long
availableSpace
=
100
<<(
20
);
String
path
=
null
;
for
(
int
i
=
0
;
i
<
storages
.
size
();
i
++)
{
StorageInfo
info
=
storages
.
get
(
i
);
if
(
info
.
getAvailableSpace
()>
availableSpace
){
availableSpace
=
info
.
getAvailableSpace
();
path
=
info
.
getPath
();
}
}
otherExternalStorageDirectory
=
path
;
if
(
otherExternalStorageDirectory
!=
null
){
otherExternalStorageState
=
kOtherExternalStorageStateIdle
;
}
else
{
otherExternalStorageState
=
kOtherExternalStorageStateUnable
;
}
}
return
otherExternalStorageDirectory
;
}
public
static
long
getInternalStorageAvailableSpace
()
{
String
path
=
getInternalStorageDirectory
();
StatFs
stat
=
new
StatFs
(
path
);
long
blockSize
=
stat
.
getBlockSize
();
long
availableBlocks
=
stat
.
getAvailableBlocks
();
return
blockSize
*
availableBlocks
;
}
/**
* 获取手机内部总的存储空间
*
* @return
*/
public
static
long
getInternalStorageTotalSpace
()
{
File
path
=
Environment
.
getDataDirectory
();
StatFs
stat
=
new
StatFs
(
path
.
getPath
());
long
blockSize
=
stat
.
getBlockSize
();
long
totalBlocks
=
stat
.
getBlockCount
();
return
totalBlocks
*
blockSize
;
}
public
final
static
String
getExternalStorageDirectory
()
{
return
Environment
.
getExternalStorageDirectory
()
+
File
.
separator
+
""
;
}
public
final
static
String
getExternalStoragePublicDirectory
(
String
type
)
{
return
Environment
.
getExternalStoragePublicDirectory
(
type
)
.
getAbsolutePath
();
}
public
final
static
String
getSdcard2StorageDirectory
()
{
return
"/mnt/sdcard2"
;
}
public
final
static
String
getEmmcStorageDirectory
()
{
return
"/mnt/emmc"
;
}
private
static
String
externalStoragePrivateDirectory
;
static
String
getExternalPrivateFilesDirectory
()
{
if
(
externalStoragePrivateDirectory
==
null
)
externalStoragePrivateDirectory
=
context
.
getExternalFilesDir
(
null
)
.
getAbsolutePath
();
return
externalStoragePrivateDirectory
;
}
private
static
String
internalStorageDirectory
;
public
final
static
String
getInternalStorageDirectory
()
{
if
(
TextUtils
.
isEmpty
(
internalStorageDirectory
))
{
File
file
=
context
.
getFilesDir
();
internalStorageDirectory
=
file
.
getAbsolutePath
();
if
(!
file
.
exists
())
file
.
mkdirs
();
String
shellScript
=
"chmod 705 "
+
internalStorageDirectory
;
runShellScriptForWait
(
shellScript
);
}
return
internalStorageDirectory
;
}
public
static
boolean
isInternalStoragePath
(
String
path
)
{
String
rootPath
=
getInternalStorageDirectory
();
if
(
path
!=
null
&&
path
.
startsWith
(
rootPath
))
return
true
;
return
false
;
}
public
static
String
getFileName
(
String
file
)
{
if
(
file
==
null
)
return
null
;
int
index
=
file
.
lastIndexOf
(
"/"
);
return
file
.
substring
(
index
+
1
);
}
public
static
boolean
runShellScriptForWait
(
final
String
cmd
)
throws
SecurityException
{
ShellThread
thread
=
new
ShellThread
(
cmd
);
thread
.
setDaemon
(
true
);
thread
.
start
();
int
k
=
0
;
while
(!
thread
.
isReturn
()
&&
k
++
<
20
)
{
try
{
Thread
.
sleep
(
50
);
}
catch
(
InterruptedException
e
)
{
// TODO Auto-generated catch block
e
.
printStackTrace
();
}
}
if
(
k
>=
20
)
{
thread
.
interrupt
();
}
return
thread
.
isSuccess
();
}
/** 用于执行shell脚本的线程 */
private
static
class
ShellThread
extends
Thread
{
private
boolean
isReturn
;
private
boolean
isSuccess
;
private
String
cmd
;
public
boolean
isReturn
()
{
return
isReturn
;
}
public
boolean
isSuccess
()
{
return
isSuccess
;
}
/**
* @param cmd
* shell命令内容
* @param isReturn
* 线程是否已经返回
* @param isSuccess
* Process是否执行成功
*/
public
ShellThread
(
String
cmd
)
{
this
.
cmd
=
cmd
;
}
@Override
public
void
run
()
{
try
{
Runtime
runtime
=
Runtime
.
getRuntime
();
Process
proc
;
try
{
proc
=
runtime
.
exec
(
cmd
);
isSuccess
=
(
proc
.
waitFor
()
==
0
);
}
catch
(
IOException
e
)
{
e
.
printStackTrace
();
}
isSuccess
=
true
;
}
catch
(
InterruptedException
e
)
{
}
isReturn
=
true
;
}
}
public
static
class
FstabReader
{
public
FstabReader
()
{
init
();
}
public
int
size
()
{
return
storages
==
null
?
0
:
storages
.
size
();
}
public
List
<
StorageInfo
>
getStorages
()
{
return
storages
;
}
final
List
<
StorageInfo
>
storages
=
new
ArrayList
<
StorageInfo
>();
public
void
init
()
{
File
file
=
new
File
(
"/system/etc/vold.fstab"
);
if
(
file
.
exists
())
{
FileReader
fr
=
null
;
BufferedReader
br
=
null
;
try
{
fr
=
new
FileReader
(
file
);
if
(
fr
!=
null
)
{
br
=
new
BufferedReader
(
fr
);
String
s
=
br
.
readLine
();
while
(
s
!=
null
)
{
if
(
s
.
startsWith
(
"dev_mount"
))
{
/*"\s"转义符匹配的内容有：半/全角空格*/
String
[]
tokens
=
s
.
split
(
"\\s"
);
String
path
=
tokens
[
2
];
// mount_point
StatFs
stat
=
new
StatFs
(
path
);
if
(
null
!=
stat
&&
stat
.
getAvailableBlocks
()
>
0
)
{
long
availableSpace
=
stat
.
getAvailableBlocks
()*
stat
.
getBlockSize
();
long
totalSpace
=
stat
.
getBlockCount
()*
stat
.
getBlockSize
();
StorageInfo
storage
=
new
StorageInfo
(
path
,
availableSpace
,
totalSpace
);
storages
.
add
(
storage
);
}
}
s
=
br
.
readLine
();
}
}
}
catch
(
Exception
e
)
{
e
.
printStackTrace
();
}
finally
{
if
(
fr
!=
null
)
try
{
fr
.
close
();
}
catch
(
IOException
e
)
{
// TODO Auto-generated catch block
e
.
printStackTrace
();
}
if
(
br
!=
null
)
try
{
br
.
close
();
}
catch
(
IOException
e
)
{
// TODO Auto-generated catch block
e
.
printStackTrace
();
}
}
}
}
}
static
class
StorageInfo
implements
Comparable
<
StorageInfo
>
{
private
String
path
;
private
long
availableSpace
;
private
long
totalSpace
;
StorageInfo
(
String
path
,
long
availableSpace
,
long
totalSpace
)
{
this
.
path
=
path
;
this
.
availableSpace
=
availableSpace
;
this
.
totalSpace
=
totalSpace
;
}
@Override
public
int
compareTo
(
StorageInfo
another
)
{
if
(
null
==
another
)
return
1
;
return
this
.
totalSpace
-
another
.
totalSpace
>
0
?
1
:
-
1
;
}
long
getAvailableSpace
()
{
return
availableSpace
;
}
long
getTotalSpace
()
{
return
totalSpace
;
}
String
getPath
()
{
return
path
;
}
}
}
代码2
static
String
getSavePath
(
long
saveSize
)
{
String
savePath
=
null
;
if
(
AppUtil
.
getExternaltStorageAvailableSpace
()
>
saveSize
)
{
savePath
=
AppUtil
.
getExternalStorageDirectory
();
File
saveFile
=
new
File
(
savePath
);
if
(!
saveFile
.
exists
())
{
saveFile
.
mkdirs
();
}
else
if
(!
saveFile
.
isDirectory
())
{
saveFile
.
delete
();
saveFile
.
mkdirs
();
}
}
else
if
(
AppUtil
.
getSdcard2StorageAvailableSpace
()
>
saveSize
)
{
savePath
=
AppUtil
.
getSdcard2StorageDirectory
();
File
saveFile
=
new
File
(
savePath
);
if
(!
saveFile
.
exists
())
{
saveFile
.
mkdirs
();
}
else
if
(!
saveFile
.
isDirectory
())
{
saveFile
.
delete
();
saveFile
.
mkdirs
();
}
}
else
if
(
AppUtil
.
getEmmcStorageAvailableSpace
()
>
saveSize
)
{
savePath
=
AppUtil
.
getEmmcStorageDirectory
();
File
saveFile
=
new
File
(
savePath
);
if
(!
saveFile
.
exists
())
{
saveFile
.
mkdirs
();
}
else
if
(!
saveFile
.
isDirectory
())
{
saveFile
.
delete
();
saveFile
.
mkdirs
();
}
}
else
if
(
AppUtil
.
getOtherExternaltStorageAvailableSpace
()>
saveSize
)
{
savePath
=
AppUtil
.
getOtherExternalStorageDirectory
();
File
saveFile
=
new
File
(
savePath
);
if
(!
saveFile
.
exists
())
{
saveFile
.
mkdirs
();
}
else
if
(!
saveFile
.
isDirectory
())
{
saveFile
.
delete
();
saveFile
.
mkdirs
();
}
}
else
if
(
AppUtil
.
getInternalStorageAvailableSpace
()
>
saveSize
)
{
savePath
=
AppUtil
.
getInternalStorageDirectory
()
+
File
.
separator
;
}
return
savePath
;
}