java - 尝试将 SQLite 数据库保存到 SD 卡

Question

这个问题已经有答案了:

已关闭 10 年前。

Possible Duplicate:
Moving my db to sd card not working

我正在尝试将 sqlite 文件保存到我的 SD 卡上。我正在使用此 question 中的代码

 try {
    File sd = Environment.getExternalStorageDirectory();
    File data = Environment.getDataDirectory();

    if (sd.canWrite()) {
        String currentDBPath = "\\data\\com.test.mytest\\databases\\test_db";
        String backupDBPath = "test_db";
        File currentDB = new File(data, currentDBPath);
        File backupDB = new File(sd, backupDBPath);

        if (currentDB.exists()) {
            FileChannel src = new FileInputStream(currentDB).getChannel();
            FileChannel dst = new FileOutputStream(backupDB).getChannel();
            dst.transferFrom(src, 0, src.size());
            src.close();
            dst.close();
        }
    }
} catch (Exception e) {
}

这是一个评价很高的答案，所以我认为它应该工作得非常简单。我在 logcat 中没有收到任何错误。我没有看到任何创建的目录/创建的文件。我的 list 中也有“写入外部”权限。

Answer 1

文件 sd = Environment.getExternalStorageDirectory(); 文件数据=Environment.getDataDirectory();

         if (sd.canWrite()) {
             String currentDBPath = "/data/packagename/databases/DATABASENAME";
             String backupDBPath = "/backup/"+"main.db";
             File currentDB = new File(data, currentDBPath);
             File backupDB = new File(sd, backupDBPath);

             if (currentDB.exists()) {
                 FileChannel src = new FileInputStream(currentDB).getChannel();
                 FileChannel dst = new FileOutputStream(backupDB).getChannel();
                 dst.transferFrom(src, 0, src.size());
                 src.close();
                 dst.close();
             } else {
                 Log.e(TAG, "File does not exist: " + currentDBPath);
             }