Intsall
Create Models
public class User extends RealmObject {
private String name; private int age; @Ignore private int sessionId; // Standard getters & setters generated by your IDE… public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public int getSessionId() { return sessionId; } public void setSessionId(int sessionId) { this.sessionId = sessionId; } } |
How to write
Realm realm = Realm.getDefaultInstance();
way 1
realm.beginTransaction();
User user = realm.createObject(User.class); // Create a new object user.setName("John"); user.setEmail("john@corporation.com"); realm.commitTransaction(); |
way 2
not block the UI thread
realm.executeTransactionAsync(new Realm.Transaction() {
@Override public void execute(Realm bgRealm) { User user = bgRealm.createObject(User.class); user.setName("John"); user.setEmail("john@corporation.com"); } }, new Realm.Transaction.OnSuccess() { @Override public void onSuccess() { // Transaction was a success. } }, new Realm.Transaction.OnError() { @Override public void onError(Throwable error) { // Transaction failed and was automatically canceled. } }); |
if use primary key
@PrimaryKey
private String name;
final String name = edName.getText().toString();
final String old = edOld.getText().toString(); Realm.Transaction transaction = new Realm.Transaction() { @Override public void execute(Realm bgrealm) { User user = new User(name, old); bgrealm.copyToRealmOrUpdate(user); } }; |
How to query
RealmResults<User> result2 = realm.where(User.class)
.equalTo("name", "John") .or() .equalTo("name", "Peter") .findAll();
result.get(result.size() - 1);
|
condition
|
and or
Each condition is implicitly logical-and together. Logical-or must be applied explicitly with or().
RealmResults<User> r = realm.where(User.class)
.greaterThan("age", 10) //implicit AND .beginGroup() .equalTo("name", "Peter") .or() .contains("name", "Jo") .endGroup() .findAll(); |
other…
Sorting
RealmResults<User> result = realm.where(User.class).findAll();
result.sort("age"); // Sort ascending result.sort("age", RealmResults.SORT_ORDER_DESCENDING); |
Auto-Updating Results
auto-updating views into the underlying data, which means results never have to be re-fetched
result = realm.where(User.class).findAll();
result.addChangeListener(new RealmChangeListener<RealmResults<User>>() { @Override public void onChange(RealmResults<User> element) { useResultToSetTheUi(element); } }); |
Delete
// obtain the results of a query
final RealmResults<Dog> results = realm.where(Dog.class).findAll(); // All changes to data must happen in a transaction realm.executeTransaction(new Realm.Transaction() { @Override public void execute(Realm realm) { // remove single match results.deleteFirstFromRealm(); results.deleteLastFromRealm(); // remove a single object Dog dog = results.get(5); dog.deleteFromRealm(); // Delete all matches results.deleteAllFromRealm(); } }); |
Thread
Using a Realm across Threads
The only rule to using Realm across threads is to remember that Realm, RealmObject or RealmResults instances cannot be passed across threads
The only rule to using Realm across threads is to remember that Realm, RealmObject or RealmResults instances cannot be passed across threads
Learn how to work with Android
use with RxJava
