新建一個類繼承 AsyncTask

 

public class BackupTask extends AsyncTask<String, Void, Integer> {
private static final String COMMAND_BACKUP = "backupDatabase";
public static final String COMMAND_RESTORE = "restroeDatabase";
private CoNtext mCoNtext;

 

public BackupTask(CoNtext coNtext) {
this.mCoNtext = coNtext;
}

 

@Override
protected Integer doInBackground(String... params) {
TODO Auto-generated method stub

 

獲得正在使用的資料庫路徑,我的是 sdcard 目錄下的 /dlion/db_dlion.db
預設路徑是 /data/data/(包名)/databases/*.db
File dbFile = mCoNtext.getDatabasePath(Environment
.getExternalStorageDirectory().getAbsolutePath()
+ "/dlion/db_dlion.db");
File exportDir = new File(Environment.getExternalStorageDirectory(),
"dlionBackup");
if (!exportDir.exists()) {
exportDir.mkdirs();
}
File backup = new File(exportDir, dbFile.getName());
String command = params[0];
if (command.equals(COMMAND_BACKUP)) {
try {
backup.createNewFile();
fileCopy(dbFile, backup);
return Log.d("backup", "ok");
} catch (Exception e) {
TODO: handle exception
e.printStackTrace();
return Log.d("backup", "fail");
}
} else if (command.equals(COMMAND_RESTORE)) {
try {
fileCopy(backup, dbFile);
return Log.d("restore", "success");
} catch (Exception e) {
TODO: handle exception
e.printStackTrace();
return Log.d("restore", "fail");
}
} else {
return null;
}
}

 

private void fileCopy(File dbFile, File backup) throws IOException {
TODO Auto-generated method stub
FileChannel inChannel = new FileInputStream(dbFile).getChannel();
FileChannel outChannel = new FileOutputStream(backup).getChannel();
try {
inChannel.transferTo(0, inChannel.size(), outChannel);
} catch (IOException e) {
TODO Auto-generated catch block
e.printStackTrace();
} finally {
if (inChannel != null) {
inChannel.close();
}
if (outChannel != null) {
outChannel.close();
}
}
}
}



在 mainActivity 裡非同步載入備份、還原:

 

資料恢復
private void dataRecover() {
TODO Auto-generated method stub
new BackupTask(this).execute("restroeDatabase");
}

 

資料備份
private void dataBackup() {
TODO Auto-generated method stub
new BackupTask(this).execute("backupDatabase");
}
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