如何在android中导出和导入领域数据

Question

我知道有些问题与我的问题相似。 但是，在某些方面我不能再进一步了。

**我无法复制下面的文件.-＆gt; realm.writeCopyTo（exportRealmFile）; **我提到的代码如下。 https://stackoverflow.com/a/36324183/6650123

让我分享我违反Realm的应用程序类。 想知道是否因为这个而无法复制领域文件..

你会看一下并提出建议吗？

**

public class MyApplication extends Application {
        private static MyApplication singleton;
        private RealmConfiguration realmConfig;

        String TAG=getClass().getName();

        public static MyApplication getSingleton(){;
            return singleton;
        }

        public void onCreate() {
            super.onCreate();
            singleton=this;
            // Create the Realm configuration
            realmConfig = new RealmConfiguration.Builder(this).build();
            Realm.setDefaultConfiguration(realmConfig);

        public void onConfigurationChanged(Configuration newConfig) {
            super.onConfigurationChanged(newConfig);
        }
        public void onLowMemory() {
            super.onLowMemory();
        }
        public void onTerminate() {
            super.onTerminate();
        }
    }

//我的备份领域代码

package com.first.project;
import android.content.Context;
import android.os.Environment;
import android.util.Log;
import android.widget.Toast;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

import io.realm.Realm;

public class RealmBackupRestore {

    private final static String TAG = RealmBackupRestore.class.getName();

    private Context context;
    private Realm realm;

    public RealmBackupRestore(Context context) {
        realm= Realm.getDefaultInstance();
        //this.realm = Realm.getInstance(BaseApplication.realmConfiguration);
        this.context = context;
    }

    public void backup() {
        Log.d(TAG, "realm은"+realm);
        Log.d(TAG, "Realm.getDefaultInstance();은"+Realm.getDefaultInstance());
        File exportRealmFile = null;
        File exportRealmPATH = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
        Log.d(TAG, "exportRealmPATH"+exportRealmPATH);
        String exportRealmFileName = "aa.realm";

        Log.d(TAG, "Realm DB Path = " + realm.getPath());

        try {
            // create a backup file
            exportRealmFile = new File(exportRealmPATH, exportRealmFileName);

            // if backup file already exists, delete it
            exportRealmFile.delete();

            // copy current realm to backup file
            realm.writeCopyTo(exportRealmFile);

        } catch (IOException e) {
            e.printStackTrace();
        }

        String msg = "File exported to Path: " +Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
        Toast.makeText(context, msg, Toast.LENGTH_LONG).show();
        Log.d(TAG, msg);


        realm.close();

    }

    public void restore() {

        //Restore
        File exportRealmPATH = context.getExternalFilesDir(null);
        String FileName = "default.realm";

        String restoreFilePath = context.getExternalFilesDir(null) + "/" + FileName;

        Log.d(TAG, "oldFilePath = " + restoreFilePath);

        copyBundledRealmFile(restoreFilePath, FileName);
        Log.d(TAG, "Data restore is done");

    }

    private String copyBundledRealmFile(String oldFilePath, String outFileName) {
        try {
            File file = new File(context.getFilesDir(), outFileName);

            Log.d(TAG, "context.getFilesDir() = " + context.getFilesDir().toString());
            FileOutputStream outputStream = new FileOutputStream(file);

            FileInputStream inputStream = new FileInputStream(new File(oldFilePath));

            byte[] buf = new byte[1024];
            int bytesRead;
            while ((bytesRead = inputStream.read(buf)) > 0) {
                outputStream.write(buf, 0, bytesRead);
            }
            outputStream.close();
            return file.getAbsolutePath();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    private String dbPath() {

        return realm.getPath();
    }
}