There is simple solution in Transformations method distinctUntilChanged.expose new data only if data was changed. In this case we get data only when it changes in source: LiveData<YourType> getData(){ return Transformations.distinctUntilChanged(LiveData<YourType> source)); } But for Event cases is better to use this: https://stackoverflow.com/a/55212795/9381524
It is usually not recommended to store image data into the database. But however if it is required for your project then you can do so. Image data are usually stored into db using BLOB data type, Room also provide support for BLOB data type Documentation You can declare your entity class as mentioned below … Read more
You can make a convert to each enum, like this: class Converters { @TypeConverter fun toHealth(value: String) = enumValueOf<Health>(value) @TypeConverter fun fromHealth(value: Health) = value.name } Or if you prefer store it as SQL integer, you can use ordinal too: class Converters { @TypeConverter fun toHealth(value: Int) = enumValues<Health>()[value] @TypeConverter fun fromHealth(value: Health) = value.ordinal … Read more
There is a more convenient solution for Kotlin with extensions: fun <T> LiveData<T>.observeOnce(lifecycleOwner: LifecycleOwner, observer: Observer<T>) { observe(lifecycleOwner, object : Observer<T> { override fun onChanged(t: T?) { observer.onChanged(t) removeObserver(this) } }) } This extension permit us to do that: liveData.observeOnce(this, Observer<Password> { if (it != null) { // do something } }) So to answer … Read more
Just add this line to you gradle.properties: kapt.incremental.apt=true
I had a similar problem using Dagger 2 that was caused by having different instances of the Dao, one for updating/inserting data, and a different instance providing the LiveData for observing. Once I configured Dagger to manage a singleton instance of the Dao, then I could insert data in the background (in my case in … Read more
Dao @Query(“SELECT * FROM Foo”) List<FooAndBar> findAllFooAndBar(); Class FooAndBar public class FooAndBar { @Embedded Foo foo; @Relation(parentColumn = “Foo.bar_id”, entityColumn = “Bar.id”) List<Bar> bar; // If we are sure it returns only one entry // Bar bar; //Getter and setter… } This solution seems to work, but I’m not very proud of it. What do … Read more
Room supports @RawQuery annotation to construct queries at run-time. Step 1 : Make DAO method Mark the DAO method with @RawQuery annotation instead of normal @Query. @Dao interface BooksDao{ @RawQuery List<Book> getBooks(SupportSQLiteQuery query); } Step 2 : Construct the query Room uses prepared statements for security and compile time verification. Therefore, while constructing queries, we … Read more
When you first come across this message, you will most likely be working against an unreleased version of the database. If that is the case, most likely you should not increment the database version. Simply clearing app data will move you passed the exception. If your app is live, you will likely need to increment … Read more
This is how I solved it, and how you can ship your application with a pre-populated database (up to Room v. alpha5) put your SQLite DB database_name.db into the assets/databases folder take the files from this repo and put them in a package called i.e. sqlAsset in your AppDatabase class, modify your Room’s DB creation … Read more