Question

我正在尝试导入/导出我的SQLite数据库，但导出正在运行。我将database.db导出到外部存储，但是当我导入时，我没有收到任何错误，但导入的记录没有得到反映。

这是我的代码。

public void importDatabase() throws IOException {

    if(isExternalStorageGranted()){
        AlertDialog.Builder alert = new AlertDialog.Builder(this);
        alert.setTitle("Import Database");
        alert.setMessage("do you want to replace database?");
        alert.setPositiveButton("YES", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                try {
                    RemindersDbAdapter objRemindersDbAdapter = new RemindersDbAdapter(ImportExportActivity.this);
                    objRemindersDbAdapter.open();
                    String oldDBPath = Environment.getExternalStorageDirectory().getPath() + separator + Constants.APP_FOLDER
                            + separator + SAMPLE_DB_NAME+".db";
                    String currentDBPath = "/data/user/0/" + getPackageName() + "/databases/" + SAMPLE_DB_NAME;

                    // database to internal oldDBPath.
                    File newDb = new File(oldDBPath);
                    File oldDb = new File(currentDBPath);

                    copyFile(new FileInputStream(oldDb), new FileOutputStream(newDb));
                    objRemindersDbAdapter.close();
                } catch (IOException e) {
                    Toast.makeText(ImportExportActivity.this, "Failed to import database", Toast.LENGTH_SHORT).show();
                }
            }
        });

        alert.setNegativeButton("NO", new DialogInterface.OnClickListener()   {
            @Override
            public void onClick(DialogInterface dialog, int which) {

            }
        });
        alert.create().show();
    }
}    

private void copyFile(FileInputStream fromFile, FileOutputStream toFile) throws IOException {
    FileChannel fromChannel = null;
    FileChannel toChannel = null;
    try {
        fromChannel = fromFile.getChannel();
        toChannel = toFile.getChannel();
        fromChannel.transferTo(0, fromChannel.size(), toChannel);
        Toast.makeText(this, "Database Imported Successfully", Toast.LENGTH_SHORT).show();
    } finally {
        try {
            if (fromChannel != null) {
                fromChannel.close();
            }
        } finally {
            if (toChannel != null) {
                toChannel.close();
            }
        }
    }
}

private void exportDB() {

    if(isExternalStorageGranted()){
        File sd = Environment.getExternalStorageDirectory();
        File data = Environment.getDataDirectory();
        FileChannel source = null;
        FileChannel destination = null;
        String currentDBPath = "/data/" + getApplicationContext().getPackageName() + "/databases/" + SAMPLE_DB_NAME;
        String backupDBPath =  SAMPLE_DB_NAME + ".db";
        File currentDB = new File(data, currentDBPath);

        File directory = new File(Environment.getExternalStorageDirectory()+File.separator+ Constants.APP_FOLDER);
        if(!directory.exists())
            directory.mkdirs();
        File backupDB = new File(directory, backupDBPath);
        LogFile.appendLog("backupDB DB Path : -" + backupDB.getPath());

        if (backupDB.exists()) {
            boolean isPrevfileDelete = backupDB.delete();
        }
        try {
            source = new FileInputStream(currentDB).getChannel();
            destination = new FileOutputStream(backupDB).getChannel();
            destination.transferFrom(source, 0, source.size());
            source.close();
            destination.close();
            Toast.makeText(this, "DB Exported!", Toast.LENGTH_LONG).show();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

我没有收到任何错误，但导入导入的记录后没有反映在sqlite数据库中。

Answer 1

当有任何打开的连接时，您不能访问数据库文件。

确保在执行任何文件操作之前关闭所有连接。

SQLite导入无效

1 个答案: