问题
Possible Duplicate:
Is it possible to copy database file to SD card?
I have a database on my Android phone, and I need to get the information onto an SD card.
Is it possible to save the database file onto the SD card in a readable state? I haven't been able to find any information on how to do this. I know the name of the database, and fields etc...
I've found some examples that show how to save to SD cards, but not exactly what I need.
Some source code that copies the database file to an SD card would be perfect.
Hopefully this question is clear enough.
回答1:
Yes. Here is the function that i use:
public void copyDBToSDCard() {
try {
InputStream myInput = new FileInputStream("/data/data/com.myproject/databases/"+DATABASE_NAME);
File file = new File(Environment.getExternalStorageDirectory().getPath()+"/"+DATABASE_NAME);
if (!file.exists()){
try {
file.createNewFile();
} catch (IOException e) {
Log.i("FO","File creation failed for " + file);
}
}
OutputStream myOutput = new FileOutputStream(Environment.getExternalStorageDirectory().getPath()+"/"+DATABASE_NAME);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0){
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
Log.i("FO","copied");
} catch (Exception e) {
Log.i("FO","exception="+e);
}
}
For a project that I worked on, I put a menu option in the home screen that I could call this function from at any time. Then, I'd move the database to my desktop and open it up with the SQLite Manager plugin for FireFox.
回答2:
Sure. If this is a database that exists in your app, you can get a reference to the db file via Context.getDatabasePath(), passing it the database name. From there, it's just a routine file copy operation:
//Get a reference to the database
File dbFile = mContext.getDatabasePath("mydb");
//Get a reference to the directory location for the backup
File exportDir = new File(Environment.getExternalStorageDirectory(), "myAppBackups");
if (!exportDir.exists()) {
exportDir.mkdirs();
}
File backup = new File(exportDir, dbFile.getName());
//Check the required operation String command = params[0];
//Attempt file copy
try {
backup.createNewFile();
fileCopy(dbFile, backup);
} catch (IOException e) {
/*Handle File Error*/
}
Where the method fileCopy() is defined as:
private void fileCopy(File source, File dest) throws IOException {
FileChannel inChannel = new FileInputStream(source).getChannel();
FileChannel outChannel = new FileOutputStream(dest).getChannel();
try {
inChannel.transferTo(0, inChannel.size(), outChannel);
} finally {
if (inChannel != null) inChannel.close();
if (outChannel != null) outChannel.close();
}
}
HTH!
来源：https://stackoverflow.com/questions/7744904/is-it-possible-to-save-database-file-to-sd-card