如何从会议室数据库向Android中的警报对话框添加列表数据

Question

我正在使用会议室数据库，我想从类别表中检索数据并在警报对话框中显示该数据最终列表类别= database.getQuery（）。getByCategory（“ Income”）;但它显示出这样的错误。

错误：找不到适用于setItems（List，）的方法方法Builder.setItems（int，android.content.DialogInterface.OnClickListener）不适用（参数不匹配；列表无法转换为int）方法Builder.setItems（CharSequence []，android.content.DialogInterface.OnClickListener）不适用（参数不匹配；列表无法转换为CharSequence []）

package com.example.mybugetssimple;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.coordinatorlayout.widget.CoordinatorLayout;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListAdapter;
import android.widget.Spinner;
import android.widget.SpinnerAdapter;
import android.widget.TextView;

import com.example.mybugetssimple.database.Category;
import com.example.mybugetssimple.database.ExpenseDatabase;
import com.google.android.material.snackbar.Snackbar;

import java.util.List;


public class AddExpenseActivity extends AppCompatActivity{

    TextView Date,catType;
    EditText amount,desc;
    ExpenseDatabase database;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add_expense);

        //Add back Button
        getSupportActionBar().setDisplayShowHomeEnabled(true);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        catType = findViewById(R.id.addExInputTv);
        Date =findViewById(R.id.addExDateInputTv);
        amount = findViewById(R.id.addExAmountInputEt);
        desc = findViewById(R.id.addExDesInputEt);
        database = ExpenseDatabase.getDatabaseInstance(this);

        final List<Category> categories = database.getQuery().getByCategory("Income");


        System.out.println(categories);

        catType.setOnClickListener( new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                final AlertDialog.Builder builder = new AlertDialog.Builder(AddExpenseActivity.this);
                builder.setTitle( "Select Income Category" );
                builder.setItems( categories, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        catType.setText(categories.get(which).getCategory_name());
                    }
                } );

                builder.setNegativeButton( "CANCEL", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        builder.setCancelable( true );
                    }
                } );

                builder.setPositiveButton( "OK", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        if (which == -1) {

                        } else {
                            catType.setText( categories.get(which).getCategory_name());

                        }


                    }
                } );
                AlertDialog alertDialog = builder.create();
                alertDialog.show();

            }
        } );





    }

    public boolean onOptionsItemSelected(@NonNull MenuItem item) {

        int id = item.getItemId();
        if(id == android.R.id.home){
            this.finish();
        }


        return super.onOptionsItemSelected(item);
    }
}

Doa文件

package com.example.mybugetssimple.database;

import androidx.lifecycle.LiveData;
import androidx.room.Dao;
import androidx.room.Insert;
import androidx.room.OnConflictStrategy;
import androidx.room.Query;

import java.util.List;

@Dao
public interface QueryDao {

    @Insert
    void category(Category ob);
    @Insert
    void category(Category...ob);

    @Insert
    void expense(Expense ob);
    @Insert
    void expense(Expense...ob);

    @Insert
    void income(Income ob);
    @Insert
    void income(Income...ob);

    @Insert
    void register(Register ob);

    @Insert(onConflict = OnConflictStrategy.IGNORE)
    void registerUser(Register ob);

    @Query("SELECT * FROM Category")
    LiveData<List<Category>> getAllCategoryList();
    @Query("SELECT * FROM EXPENSE")
    List<Expense> getAllExpenseList();
    @Query("SELECT * FROM INCOME")
    List<Income> getAllIncomeLIst();

    @Query("SELECT * FROM REGISTER WHERE Email=:emailId and password=:passwordId")
    Register getUser(String emailId, String passwordId);

    @Query("SELECT *FROM Register")
    List<Register> getUser();

    @Query("SELECT Email FROM REGISTER WHERE Email =:emailId")
    Register getEmail(String emailId);

    @Query("SELECT category_id, category_name FROM CATEGORY WHERE category_type =:catType")
     List<Category> getByCategory(String catType);


}

//

Answer 1

Afaik setItems接收一个String数组。因此，看起来您应该生成包含类别名称的String [] catNames，并将其与setItems一起使用。

在用户按下OK后，您应该在对话框中查找一个类别为category_name的类别。