Android 判断SD卡是否存在及容量查询

<!-- 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"/>

private boolean ExistSDCard() {
if (android.os.Environment.getExternalStorageState().equals(
android.os.Environment.MEDIA_MOUNTED)) {
return true;
} else
return false;
}

public long getSDFreeSize(){
//取得SD卡文件路径
File path = Environment.getExternalStorageDirectory();
StatFs sf = new StatFs(path.getPath());
//获取单个数据块的大小(Byte)
long blockSize = sf.getBlockSize();
//空闲的数据块的数量
long freeBlocks = sf.getAvailableBlocks();
//返回SD卡空闲大小
//return freeBlocks * blockSize;  //单位Byte
//return (freeBlocks * blockSize)/1024;   //单位KB
return (freeBlocks * blockSize)/1024 /1024; //单位MB
}

public long getSDAllSize(){
//取得SD卡文件路径
File path = Environment.getExternalStorageDirectory();
StatFs sf = new StatFs(path.getPath());
//获取单个数据块的大小(Byte)
long blockSize = sf.getBlockSize();
//获取所有数据块数
long allBlocks = sf.getBlockCount();
//返回SD卡大小
//return allBlocks * blockSize; //单位Byte
//return (allBlocks * blockSize)/1024; //单位KB
return (allBlocks * blockSize)/1024/1024; //单位MB
}