This doesn’t answer the original question How can I properly re-open room db after I close it? However, moving everything to the original database file is what you want to do, then you don’t have to close the database in the first place. You can instead force a checkpoint using the wal_checkpoint pragma. Query the … Read more
You can use my helper method: val profile = MutableLiveData<ProfileData>() val user = MutableLiveData<CurrentUser>() val title = profile.combineWith(user) { profile, user -> “${profile.job} ${user.name}” } fun <T, K, R> LiveData<T>.combineWith( liveData: LiveData<K>, block: (T?, K?) -> R ): LiveData<R> { val result = MediatorLiveData<R>() result.addSource(this) { result.value = block(this.value, liveData.value) } result.addSource(liveData) { result.value = … Read more
Usually in project build.gradle I define the dependencies versions: ext { buildToolsVersion = ‘25.0.2’ supportLibVersion = ‘25.3.1’ espressoVersion = ‘2.2.2’ archRoomVersion = ‘1.0.0-alpha1’ } so in app build.gradle the dependencies look like: dependencies { compile fileTree(dir: ‘libs’, include: [‘*.jar’]) compile “org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version” compile “com.android.support:appcompat-v7:${rootProject.supportLibVersion}” compile “android.arch.persistence.room:runtime:${rootProject.archRoomVersion}” annotationProcessor “android.arch.persistence.room:compiler:${rootProject.archRoomVersion}” kapt “android.arch.persistence.room:compiler:${rootProject.archRoomVersion}” androidTestCompile(“com.android.support.test.espresso:espresso-core:${rootProject.espressoVersion}”, { exclude group: ‘com.android.support’, module: … Read more
There is a more convenient solution for Kotlin with extensions: fun <T> LiveData<T>.observeOnce(lifecycleOwner: LifecycleOwner, observer: Observer<T>) { observe(lifecycleOwner, object : Observer<T> { override fun onChanged(t: T?) { observer.onChanged(t) removeObserver(this) } }) } This extension permit us to do that: liveData.observeOnce(this, Observer<Password> { if (it != null) { // do something } }) So to answer … Read more
You need to use the autoGenerate property Your primary key annotation should be like this: @PrimaryKey(autoGenerate = true) Reference for PrimaryKey.
So how could I uses this to circumvent the Invalid Schema expected …. found ….? The following, albeit long winded shows an example that corrects a schema accordingly. Could I use this to introduce Triggers, as room doesn’t have annotations for the creation of triggers? Yes, although this hasn’t actually been tested but the example … Read more
There is simple solution in Transformations method distinctUntilChanged.expose new data only if data was changed. In this case we get data only when it changes in source: LiveData<YourType> getData(){ return Transformations.distinctUntilChanged(LiveData<YourType> source)); } But for Event cases is better to use this: https://stackoverflow.com/a/55212795/9381524
Changed in gradle from this: kapt “androidx.room:room-compiler:$roomVersion” to this: annotationProcessor “androidx.room:room-compiler:$room_version”
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