Android文件管理常用的方法

boolean checkFileExists (String name){
boolean status;
if ((testSaveLocationExists())&&(!name.equals(""))){
    File path = Environment.getExternalStorageDirectory();
            File newPath = new File(path.toString()+ name);
            status = newPath.exists();
    }else{
    status = false;
    }
return status;

}

long getFreeDiskSpace(){
/*
* gets the available SD card free space or returns -1 if the SD card is not mounted.
*/
String status = Environment.getExternalStorageState();
long freeSpace = 0;
if (status.equals(Environment.MEDIA_MOUNTED)) {
try {
File path = Environment.getExternalStorageDirectory();
StatFs stat = new StatFs(path.getPath());
long blockSize = stat.getBlockSize();
long availableBlocks = stat.getAvailableBlocks();
freeSpace = availableBlocks*blockSize/1024;
} catch (Exception e) {e.printStackTrace(); }
} else { return -1; }
return (freeSpace);
}

boolean createDirectory(String directoryName){
boolean status;
if ((testSaveLocationExists())&&(!directoryName.equals(""))){
File path = Environment.getExternalStorageDirectory();
            File newPath = new File(path.toString()+ directoryName);
status = newPath.mkdir();
status = true;
}else
status = false;
return status;
}

boolean checkSaveLocationExists(){
String sDCardStatus = Environment.getExternalStorageState();
boolean status;
if (sDCardStatus.equals(Environment.MEDIA_MOUNTED)){
status = true;
}else
status = false;
return status;
}

boolean deleteDirectory(String fileName){
boolean status;
SecurityManager checker = new SecurityManager();

if ((testSaveLocationExists())&&(!fileName.equals(""))){

File path = Environment.getExternalStorageDirectory();
            File newPath = new File(path.toString()+fileName);
checker.checkDelete(newPath.toString());
if(newPath.isDirectory()){
String[] listfile = newPath.list();
// delete all files within the specified directory and then delete the directory
try{
for (int i=0; i < listfile.length; i++){
File deletedFile = new File (newPath.toString()+"/"+listfile[i].toString());
deletedFile.delete();
}
newPath.delete();
Log.i("DirectoryManager deleteDirectory", fileName);
status = true;
}catch (Exception e){
e.printStackTrace();
status = false;
}

}else
status = false;
}else
status = false;
return status;
}

boolean deleteFile(String fileName){
boolean status;
SecurityManager checker = new SecurityManager();

if ((testSaveLocationExists())&&(!fileName.equals(""))){

File path = Environment.getExternalStorageDirectory();
            File newPath = new File(path.toString()+fileName);
checker.checkDelete(newPath.toString());
if (newPath.isFile()){
try {
Log.i("DirectoryManager deleteFile", fileName);
newPath.delete();
status = true;
}catch (SecurityException se){
se.printStackTrace();
status = false;
}
}else
status = false;
}else
status = false;
return status;
}