Android数据库安全解决方案，使用SQLCipher进行加解密

private void copyFile(final String filename){
File file = new File(getFilesDir(),filename);
if(file.exists()&&file.length()>0){
Log.i("TAG","数据库存在，无需拷贝");
}
new Thread(new Runnable() {
@Override
public void run() {
//把assets资产目录里面的文件（在apk里面的）拷贝到手机系统里面
try {
InputStream is = getAssets().open(filename);
File file = new File(getFilesDir(),filename);
FileOutputStream fos = new FileOutputStream(file);
byte[] buffer = new byte[1024];
int len = -1;
while((len = is.read(buffer))!=-1){
fos.write(buffer,0,len);
}
fos.close();
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
}