AutocompleteTextView with room

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.CustomerDao().getAllCustomers() as MutableLiveData<List<Customer>>
    }
}

回答1:

 step 1:create custom autocomplete text view

     example:https://spapas.github.io/2019/04/05/android-custom-filter-adapter/

 step2:get data from room dp

       @Query("SELECT * FROM Gender WHERE name == :name")
       fun getGenderByName(name: String): List<Gender>

 step3:update this data to  custom autocomplete adapter

回答2:

If i understand you want to have as entries of your autocomplete text view the data that you have in the internal DB.

To do that i create my custom ViewModel with allStudentsData, repository an listen from activity

1. Repository Class A repository that is listening directly from DB

   val allStudents: LiveData<List<Student>> = studentDao.getAll()

2. ViewModel Class

`private val allStudents: LiveData> init {

    val studentsDao = AppDatabase.getDatabase(application,viewModelScope).studentsDao()
    studentRepository = StudentRepository(studentsDao)
    allStudents = studentRepository.allStudents
}`

3. Activity Class

   private lateinit var studentViewModel: StudentViewModel

   public override fun onCreate(savedInstanceState: Bundle?) {

   super.onCreate(savedInstanceState)
   setContentView(R.layout.activity_main)
   
   studentViewModel = ViewModelProvider(this).get(StudentViewModel::class.java)
   studentViewModel.allStudents.observe(this, Observer { students ->
       // Update the cached copy of the students in the adapter.
       students?.let {
           val arr = mutableListOf<String>()
   
           for (value in it) {
               arr.add(value.name)
           }
           val adapter: ArrayAdapter<String> =
               ArrayAdapter(this, android.R.layout.select_dialog_item, arr)
           names.setAdapter(adapter)
       }
   })
   

   }

In the activity we have a viewModel variable that observe the data that is change when new record is insert in DB. When we have new data Observer {} is called, so with the new list of students we create a mutable list, we add all students and we set the adapter

By doing this, when data change in DB

DB ====> Repository ====> ViewModel ====> Activity

来源：https://stackoverflow.com/questions/59136390/autocompletetextview-with-room