在存储文件时，为了保证有充足的存储空间大小，通常需要知道系统内部或者sdcard的剩余存储空间大小，这里就需要用到StatFs类。
1. 判断 SDCard 是否存在,并且是否具有可读写权限
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/**
* 外部存储是否可用 (存在且具有读写权限)
* @return
*/
staticpublicboolean isExternalStorageAvailable() {
return Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED);
}
/**
* 外部存储是否可用 (存在且具有读写权限)
* @return
*/
static public boolean isExternalStorageAvailable() {
return Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED);
}
2.获取手机系统可用空间大小
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/**
* 获取手机内部可用空间大小
* @return
*/
staticpubliclong getAvailableInternalMemorySize() {
File path = Environment.getDataDirectory();
StatFs stat = new StatFs(path.getPath());
long blockSize = stat.getBlockSize();
long availableBlocks = stat.getAvailableBlocks();
return availableBlocks * blockSize;
}
/**
* 获取手机内部可用空间大小
* @return
*/
static public long getAvailableInternalMemorySize() {
File path = Environment.getDataDirectory();
StatFs stat = new StatFs(path.getPath());
long blockSize = stat.getBlockSize();
long availableBlocks = stat.getAvailableBlocks();
return availableBlocks * blockSize;
}
3.获取手机内部总空间大小
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/**
* 获取手机内部空间大小
* @return
*/
staticpubliclong getTotalInternalMemorySize() {
File path = Environment.getDataDirectory();//Gets the Android data directory
StatFs stat = new StatFs(path.getPath());
long blockSize = stat.getBlockSize(); //每个block 占字节数
long totalBlocks = stat.getBlockCount(); //block总数
return totalBlocks * blockSize;
}
/**
* 获取手机内部空间大小
* @return
*/
static public long getTotalInternalMemorySize() {
File path = Environment.getDataDirectory();//Gets the Android data directory
StatFs stat = new StatFs(path.getPath());
long blockSize = stat.getBlockSize(); //每个block 占字节数
long totalBlocks = stat.getBlockCount(); //block总数
return totalBlocks * blockSize;
}
4.获取手机外部可用空间大小、获取手机外部总空间大小
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/**
* 获取手机外部可用空间大小
* @return
*/
staticpubliclong getAvailableExternalMemorySize() {
if (isExternalStorageAvailable()) {
File path = Environment.getExternalStorageDirectory();//获取SDCard根目录
StatFs stat = new StatFs(path.getPath());
long blockSize = stat.getBlockSize();
long availableBlocks = stat.getAvailableBlocks();
return availableBlocks * blockSize;
} else {
return -1;
}
}
/**
* 获取手机外部总空间大小
* @return
*/
staticpubliclong getTotalExternalMemorySize() {
if (isExternalStorageAvailable()) {
File path = Environment.getExternalStorageDirectory(); //获取SDCard根目录
StatFs stat = new StatFs(path.getPath());
long blockSize = stat.getBlockSize();
long totalBlocks = stat.getBlockCount();
return totalBlocks * blockSize;
} else {
return -1;
}
}
/**
* 获取手机外部可用空间大小
* @return
*/
static public long getAvailableExternalMemorySize() {
if (isExternalStorageAvailable()) {
File path = Environment.getExternalStorageDirectory();//获取SDCard根目录
StatFs stat = new StatFs(path.getPath());
long blockSize = stat.getBlockSize();
long availableBlocks = stat.getAvailableBlocks();
return availableBlocks * blockSize;
} else {
return -1;
}
}
/**
* 获取手机外部总空间大小
* @return
*/
static public long getTotalExternalMemorySize() {
if (isExternalStorageAvailable()) {
File path = Environment.getExternalStorageDirectory(); //获取SDCard根目录
StatFs stat = new StatFs(path.getPath());
long blockSize = stat.getBlockSize();
long totalBlocks = stat.getBlockCount();
return totalBlocks * blockSize;
} else {
return -1;
}
}
注意： 访问SDCard进行文件读写时：
在AndroidManifest.xml中加入访问SDCard的权限如下:
<!-- 在SDCard中创建与删除文件权限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<!-- 往SDCard写入数据权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
接着我们在使用SDcard进行读写的时候 会用到Environment类下面的几个静态方法：
1:getDataDirectory() 获取到Android中的data数据目录
2:getDownloadCacheDirectory() 获取到下载的缓存目录
3:getExternalStorageDirectory() 获取到外部存储的目录 一般指SDcard
4:getExternalStorageState() 获取外部设置的当前状态 一般指SDcard,
android系统中对于外部设置的状态，比较常用的是 MEDIA_MOUNTED（SDcard存在且可以进行读写） MEDIA_MOUNTED_READ_ONLY (SDcard存在，只可以进行读操作) 当然还有其他的一些状态，可以在文档中进行查找到。
5:getRootDirectory() 获取到Android Root路径
6:isExternalStorageEmulated() 返回Boolean值判断外部设置是否有效
7:isExternalStorageRemovable() 返回Boolean值，判断外部设置是否可以移除
