在android中删除Realm中的单个对象数据/行

Posted 2021-03-26

我添加了单个用户的数据像这样：

Realm realm = Realm.getDefaultInstance();
newUser = new UserDatabase();

realm.executeTransaction(new Realm.Transaction() {

  public void execute(Realm realm) {
     newUser.setClassName(classSectionName);
     newUser.setClassNO(classNO);
     newUser.setImageUrl(imageUrl);
     newUser.setRollNo(rollNO);
     newUser.setSchool(school);              

  // and now saved the data in peresistant data like this:
  realm.copyToRealm(newUser);
  }
});

但我无法找到从Realm数据库中删除单个条目的方法，即使我尝试这样，它也无法正常工作。

Realm realm = Realm.getDefaultInstance();
UserDatabase tempUser = new UserDatabase();
final RealmResults<UserDatabase> students = realm.where(UserDatabase.class).findAll();

  for(int i=0 ;  i<students.size();i++){
     final int index =i;
     if((students.get(i).getUserID()).equals(prefs.getString(QRActivity.USER_ID_AFTER_LOGIN,"jpt"))&&
     (students.get(i).getUserName()).equals(prefs.getString(QRActivity.USER_NAME_AFTER_LOGIN,"jpt"))){

        realm.executeTransaction(new Realm.Transaction() {

            public void execute(Realm realm) {

             //Trying to delete a row from realm.                                   

             students.deleteFromRealm(index);

             }
            });

    }
 }

有谁有想法吗 ？

答案

你总是可以使用instance从RealmResults<UserDatabase>找到匹配的Realm Query，而不是运行循环。试试这个。

    final RealmResults<UserDatabase> students = realm.where(UserDatabase.class).findAll();

    UserDatabase userdatabase = students .where().equalTo("userId",prefs.getString(QRActivity.USER_ID_AFTER_LOGIN,"jpt")).equalTo("userName",prefs.getString(QRActivity.USER_NAME_AFTER_LOGIN,"jpt")).findFirst();

    if(userdatabase!=null){

    if (!realm.isInTransaction())
     {
       realm.beginTransaction();
     }

     userdatabase.deleteFromRealm();

      realm.commitTransaction();
    }

注意：我只假设您的列中有“userId”和“userName”，您可以改为编写列名。