android-studio - lateinit 属性 mUserViewModel 尚未初始化

问题描述

我正在尝试读取我的数据库，因此我创建了一个编辑文本，我将在其中输入用户名和一个允许我搜索用户的按钮，但我在 ListFragment 类中显示错误：Fragment()，它说lateinit 属性 mUserViewModel 尚未初始化，请帮助我:(。

//实体

@Entity(tableName = "user_table")
data class User(
    @PrimaryKey(autoGenerate = true)
    val id: Int,
    val firstName: String,
    val lastName: String,
    val age: Int
)

//道

@Dao
interface UserDao {

    @Insert(onConflict = OnConflictStrategy.IGNORE)
    suspend fun addUser(user: User)
    @Query("SELECT * FROM user_table where firstName LIKE :search LIMIT 1")
    suspend fun readAllData(search : String) : User

}

//用户存储库

class UserRepository(private val userDao: UserDao) {
    suspend fun readAllData(user: String):User{
       return userDao.readAllData(user)
    }
}

//用户视图模型

class UserViewModel(application: Application): AndroidViewModel(application) {
    
   private lateinit var repository:UserRepository
    
    fun search( search : String):User{
        viewModelScope.launch {
            repository.readAllData(search)
        }
  
        return search(String())
    }

}

}

//班级

class ListFragment : Fragment() {
    //erro(lateinit property mUserViewModel has not been initialized)
                lateinit var mUserViewModel:UserViewModel
                override fun onCreateView(
                    inflater: LayoutInflater, container: ViewGroup?,
                    savedInstanceState: Bundle?
                ): View? {
                    // Inflate the layout for this fragment
                    val view = inflater.inflate(R.layout.fragment_list, container, false)
            
                    val name = view.editTextTextNameee.text.toString()
                   val prueba = mUserViewModel.search(name)
            
                    if (prueba!=null){
            
                        textView1.text = prueba.firstName
                        textView2.text = prueba.lastName
                        textView3.text = prueba.age.toString()
                    }else {
                        Toast.makeText(context, " Unregistered use", Toast.LENGTH_SHORT).show()
                    }
            
            
                    view.floatingActionButton.setOnClickListener {
                        findNavController().navigate(R.id.action_listFragment_to_addFragment)
                    }
            
                    return view
                }
            }

标签： android-studioandroid-roomandroid-livedatakotlin-coroutinesandroid-viewmodel

android-studio - lateinit 属性 mUserViewModel 尚未初始化

问题描述

解决方案

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