Question

我想将我的领域数据库复制到SD卡为此，我使用此代码：

 byte[] key=new byte[64];
            new SecureRandom().nextBytes(key);
            Realm realm = Realm.getInstance(App.realmConfiguration);
            try {
                realm.writeEncryptedCopyTo(new File(Environment.getExternalStorageDirectory(), "encryptRealm.txt"),key);
                Toast.makeText(getApplicationContext(),"success saving",Toast.LENGTH_LONG).show();
            } catch (IOException e) {
                e.printStackTrace();
                Toast.makeText(getApplicationContext(),"error saving",Toast.LENGTH_LONG).show();
            }


            try {
                realm.writeCopyTo(new File(Environment.getExternalStorageDirectory(),"simpleRealm.txt"));
                Toast.makeText(getApplicationContext(),"success saving",Toast.LENGTH_LONG).show();
            } catch (IOException e) {
                Toast.makeText(getApplicationContext(),"error saving",Toast.LENGTH_LONG).show();
                e.printStackTrace();
            }

但是当我运行我的应用时，我收到此错误消息：

at io.realm.internal.Group.nativeWriteToFile(Native Method)
at io.realm.internal.Group.writeToFile(Group.java:226)
at io.realm.internal.SharedGroupManager.copyToFile(SharedGroupManager.java:141)
at io.realm.BaseRealm.writeEncryptedCopyTo(BaseRealm.java:254)
at io.realm.Realm.writeEncryptedCopyTo(Realm.java:122)
at com.medium.ir.test.MainActivity$2.onClick(MainActivity.java:73)
at android.view.View.performClick(View.java:4633)
at android.view.View$PerformClick.run(View.java:19270)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5476)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
at dalvik.system.NativeStart.main(Native Method)

但是当我将复制文件的文件位置更改为此

时

realm.writeEncryptedCopyTo(new File(context.getFilesDir(), "new-name"), getNewKey());

我的应用程序崩溃但我无法获取我的领域数据库文件。＆＃34; root access nedded＆＃34;
顺便说一下，这个ligale是用sd卡复制realm数据库的吗？谁能帮帮我呢？

Answer 1

首先检查您的应用程序类在onCreateMethod()中是否具有以下代码

public class MyApplication extends Application {

@Override
public void onCreate() {
    super.onCreate();
    Realm.init(this);
    RealmConfiguration.Builder configBuilder = new RealmConfiguration.Builder()
            .name("yourDbName.realm")
            .migration(migration)
            .schemaVersion(REALM_DB_VERSION);//Your db version
    Realm.setDefaultConfiguration(configBuilder.build());

}

现在，将此代码粘贴到要将数据导出到外部存储的位置。

final Realm realm = Realm.getDefaultInstance();

try {
    final File file = new File(Environment.getExternalStorageDirectory().getPath().concat("/sample.realm"));
    if (file.exists()) {
        file.delete();
    }

    realm.writeCopyTo(file);
    Toast.makeText(MyActivity.this, "Successful export to a realm file", Toast.LENGTH_SHORT).show();
} catch (Exception e) {
    realm.close();
    e.printStackTrace();
}

仅此而已：）

在存储中复制领域数据库

1 个答案: