android-room

问题 I have just started using android development and trying to use Room library. Since yesterday I am facing this warning message w: [kapt] Incremental annotation processing requested, but support is disabled because the following processors are not incremental: androidx.lifecycle.LifecycleProcessor (NON_INCREMENTAL), androidx.room.RoomProcessor (NON_INCREMENTAL). I have tried to research and fix but unable to avoid this error here is my grale.build file. please suggest/advice what I am doing

问题 While updating Room database I get an error: Fatal Exception: java.lang.IllegalStateException: attempt to re-open an already-closed object: SQLiteDatabase: ***************** at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:55) at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1312) at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1291) at android.arch.persistence.db.framework.FrameworkSQLiteDatabase

问题 I'm facing a problem with Room database, when trying to use insert method that I declared in Dao Class to write a data into database this error shows up: Unique constraint failed Any idea way? Dao Class @Dao public interface TaskDao { @Query("SELECT * FROM task") List<Task> getall(); @Insert void insert(Task task); @Delete void delete(Task task); } AppDatabase Class @Database(entities = {Task.class}, version = 1) public abstract class AppDatabase extends RoomDatabase { public abstract TaskDao

问题 I'm facing a problem with Room database, when trying to use insert method that I declared in Dao Class to write a data into database this error shows up: Unique constraint failed Any idea way? Dao Class @Dao public interface TaskDao { @Query("SELECT * FROM task") List<Task> getall(); @Insert void insert(Task task); @Delete void delete(Task task); } AppDatabase Class @Database(entities = {Task.class}, version = 1) public abstract class AppDatabase extends RoomDatabase { public abstract TaskDao

问题 How can I do the following? I want to select a specific column in my room query. This column will be specified by as a parameter in the query function. Imagine my database looks like the following: +----+---------+---------+---------+---------+ | ID | Column1 | Column2 | Column3 | Column4 | +----+---------+---------+---------+---------+ | 1 | 13 | 45 | 77 | 12 | +----+---------+---------+---------+---------+ | 2 | 5 | 34 | 67 | 7 | +----+---------+---------+---------+---------+ | 3 | 8 | 33 |

问题 I have java objects which are are backed by a HashMap and thus do not have plain fields which can be discovered via reflection. For example: public class City { private final HashMap<String, String> internalMap = new HashMap<String, String>(); public String getId() { return internalMap.get("id"); } public void setId(String id) { internalMap.put("id", id); } public String getName() { return internalMap.get("name"); } public void setName(String name) { internalMap.put("name", name); } } I want

问题 I am trying to build an app that will rely on a Webservice to work. To make it, I decided to follow the Model-View-ViewModel architecture together with the Repository pattern. I try to make this architecture inspired by the guidelines shown in Guide to App architecture, from Android Developer's Official Site. I use OkHttp library to consume the WebService, and Room for the phone's database. I made some testing to see if the app obtained succesfully the Data through the Webservice, from inside

问题 I am trying to build an app that will rely on a Webservice to work. To make it, I decided to follow the Model-View-ViewModel architecture together with the Repository pattern. I try to make this architecture inspired by the guidelines shown in Guide to App architecture, from Android Developer's Official Site. I use OkHttp library to consume the WebService, and Room for the phone's database. I made some testing to see if the app obtained succesfully the Data through the Webservice, from inside

问题 I'm trying my hand at using Android Room and after following this tutorial I'm getting the following error when i try to build the app: Error:(23, 27) error: There is a problem with the query: [SQLITE_ERROR] SQL error or missing database (no such table: screen_items) The name is fine and should exist. After making my changes I cleaned the project and made sure it was completely uninstalled from the device. In my Activity I'm initialising the things in onCreate with this line: db = AppDatabase

问题 I have a Room db and have created a model and viewModel. I was wondering how to make an autocompletetextview work with the database data and the viewmodel to filter the customer list as the user types ViewModel class CustomerVM : ViewModel() { private val customers: MutableLiveData<List<Customer>> by lazy { loadCustomers() } fun getCustomers(): LiveData<List<Customer>> { return customers } private fun loadCustomers() : MutableLiveData<List<Customer>> { return DataModel.getInstance().roomDb