Android导出APK里的数据库.db文件至SD卡

// 参考: http://code.google.com/p/and-examples/source/browse/#svn/trunk/database/src/com/totsp/database
private class ExportDatabaseTask extends AsyncTask<Void, Void, String> {

private final ProgressDialog dialog = new ProgressDialog(mContext);

// can use UI thread here

@Override

protected void onPreExecute() {

this.dialog.setMessage("正在导出数据库文件至SD卡，请稍候...");

this.dialog.show();

}

// automatically done on worker thread (separate from UI thread)

@Override

protected String doInBackground(final Void... args) {

if (!Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {

return "未找到SD卡";

}

//setting.db为apk里的一个数据库文件

File dbFile = new File(Environment.getDataDirectory() + "/data/com.goodboyenglish.leo/databases/setting.db");

//"goodboyenglish_setting.db"为要备份至SD卡上的数据库文件名称

File file = new File(Environment.getExternalStorageDirectory(), "goodboyenglish_setting.db");

try {

//创建一个文件，如果文件存在的话会自动把原来的覆盖掉

file.createNewFile();

//拷贝文件

copyFile(dbFile, file);

return "成功导出数据库文件至SD卡!";

} catch (IOException e) {

return "导出失败!";

}

}

// can use UI thread here

@Override

protected void onPostExecute(final String msg) {

if (this.dialog.isShowing()) {

this.dialog.dismiss();

}

Toast.makeText(mContext, msg, Toast.LENGTH_SHORT).show();

}

}

//拷贝文件的函数 src 为需要复制的文件，dst为目标文件(被src覆盖的文件)

//拷贝的过程其实就是把src文件里内容写入dst文件里的过程(从头写到尾)

public static void copyFile(File src, File dst) throws IOException {

FileChannel inChannel = new FileInputStream(src).getChannel();

FileChannel outChannel = new FileOutputStream(dst).getChannel();

try {

inChannel.transferTo(0, inChannel.size(), outChannel);

} finally {

if (inChannel != null)

inChannel.close();

if (outChannel != null)

outChannel.close();

}

}

调用方式:new ExportDatabaseTask().execute();