基于用户输入的过滤器 - LiveData、Recycler、RoomView

Question

我的 Android 应用程序有一个 SQLite 数据库。数据库有一个 table 用于 properties ，另一个 table 用于 repairs 在每个属性。

Table 维修 :

@Entity(tableName = "repairs",
        indices = {@Index(value = "repairID", unique = true), @Index("repairPropID")})

public class MYRepairs
{
    @PrimaryKey(autoGenerate = true)
    @ColumnInfo(name = "repid")
    public int id;

    @ColumnInfo(name = "repairID")
    @NonNull
    public String repairID;

    @ColumnInfo(name = "repairPropID")
    public int repairPropID;
}

...

然后是RepairsDao.java

 @Dao
    public interface MyRepairsDao
    {
        @Query("SELECT * FROM repairs WHERE repid = :repid LIMIT 1")
        MYRepairs findRepairById(String repid);


        @Query("SELECT * FROM repairs WHERE repairPropID = :repairPropID")
        MYRepairs findRepairByPropID(int repairPropID);


        @Query("SELECT * FROM repairs ORDER BY repairPropID ASC")
        LiveData<List<MYRepairs>> getAllRepairs();

 @Query("SELECT * FROM repairs WHERE repairPropID = :repairPropID")
    LiveData<List<MYRepairs>> getPropertyRepairs(int repairPropID);

    }

在ViewModel中：

   public class repairViewModel extends AndroidViewModel
    {
        private MyRepairsDao myRepairDao;
        private LiveData<List<MYRepairs>> repairLiveData;
        private LiveData<List<MYRepairs>> repairPropertyLiveData;
        private LiveData<String> filterLiveData = new MutableLiveData<String>();

        public repairViewModel(@NonNull Application application)
        {
            super(application);
            myRepairDao = DogwoodDatabase.getDatabase(application).repairDao();
            repairLiveData = myRepairDao.getAllRepairs();
            repairPropertyLiveData = myRepairDao.getPropertyRepairs(propertyID);
        }

        public LiveData<List<MYRepairs>> getAllRepairs()
        {
            return repairLiveData;
        }

        public LiveData<List<MYRepairs>> getPropertyRepairs(int propertyID) 
        { 
            return repairPropertyLiveData; 
        }

并且在RecyclerView.Adapter中：

public class repairListAdapter extends RecyclerView.Adapter<repairListAdapter.RepairViewHolder>
{
@NonNull
        @Override
        public repairListAdapter.RepairViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType)
        {
            final View itemView = layoutInflater.inflate(R.layout.repaircontent, parent, false);
            return new repairListAdapter.RepairViewHolder(itemView);
        }

在 repairFragment 中 - 我们只想查看所选属性用户的 维修。属性代码 属性ID 由 repairFragement 接收。 initData()

已知
public class repairFragment extends Fragment { private repairListAdapter repairListAdapter; private repairViewModel repairViewModel; public void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); propertyID = getArguments().getString("ARG_PROPNUM_ID"); propNumID = Integer.parseInt(propertyID); initData(); } private void initData() { Log.e ("INIT", "ID is " + propertyID); repairViewModel = new ViewModelProvider(this).get(repairViewModel.class); repairViewModel.getPropertyRepairs(propertyID).observe(this, new Observer<List<MYRepairs>>() { @Override public void onChanged(@Nullable List<MYRepairs> MYRepairs) { repairListAdapter.setMYRepairList(MYRepairs); } }); }

这 returns 没有记录。在一个理想的世界里，我的财产没有维修，但我不生活在那个世界里！

我已搜索过此版块以寻求有关过滤的帮助。

您能否帮助我如何过滤仅针对选定的属性 (属性ID) 用户的维修。

谢谢，瑞秋

Answer 1

天哪！我想到了。

正在修复ViewModel：

public LiveData<List<MYRepairs>> getPropertyRepairs(int propertyID)
    {

        repairPropertyLiveData = myRepairDao.getPropertyRepairs(propertyID);
        return repairPropertyLiveData;
    }

Answer 2

您想做的是：

public LiveData<List<MYRepairs>> getPropertyRepairs() { 
    return repairPropertyLiveData; 
}

和

private MutableLiveData<String> selectedPropertyId = new MutableLiveData<>();

private final repairPropertyLiveData = Transformations.switchMap(selectedPropertyId, (id) -> {
    return myRepairDao.getPropertyRepairs(id);
});

public void updateSelectedProperty(String propertyId) {
    selectedPropertyId.setValue(propertyId);
}

这样，您就不会得到未正确失效的新订阅，以防您稍后 select 一个不同的属性 id。

基于用户输入的过滤器 - LiveData、Recycler、RoomView

Filter based on user input - LiveData, Recycler, RoomView

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android-room

android-livedata