Flutter 从现有数据库 sqflite 中获取数据

Question

你好朋友我是初学者学习 sqflite 我的任务是从现有的数据库中获取数据并显示在 listview.builder 我搜索 youtube 和其他资源但没有找到请帮助我这里是我现有的数据库助手 class 和 listview class 我需要显示我的数据库的地方请帮我检查下面的代码

//existing database helper class

import 'dart:io';
import 'package:flutter/services.dart';
import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart';


    class Dbhelper{
       Database? database;
      Future<Database?> get db async{
        if(database!=null){
          print('Database is already existing');
          return database;
        }
        else{
          database=await initdb();
          return database;
        }
    
      }
    
      Future initdb()async {
        var databasesPath = await getDatabasesPath();
        var path = join(databasesPath, "bible.db");
    
    // Check if the database exists
        var exists = await databaseExists(path);
    
        if (!exists) {
          // Should happen only the first time you launch your application
          print("Creating new copy from asset");
    
          // Make sure the parent directory exists
          try {
            await Directory(dirname(path)).create(recursive: true);
          } catch (_) {}
    
          // Copy from asset
          ByteData data = await rootBundle.load(join("asset", "bible.db"));
          List<int> bytes =
          data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
    
          // Write and flush the bytes written
          await File(path).writeAsBytes(bytes, flush: true);
        }
    
        else {
          print("Opening existing database");
        }
    // open the database
        return await openDatabase(path, readOnly: true);
      }
    
    
       }


//here i want show my data in list view.builder



    import 'dart:math';
    
    import 'package:bibleapp/Verse.dart';
    import 'package:flutter/material.dart';
    
    class chapters extends StatefulWidget {
      const chapters({Key? key}) : super(key: key);
    
      @override
      _chaptersState createState() => _chaptersState();
    }
    
    class _chaptersState extends State<chapters> {
      @override
      Widget build(BuildContext context) {
        return Scaffold(
          appBar: AppBar(
            title: Text('SELECT CHAPTER'),
          ),
          body: Padding(
            padding: EdgeInsets.all(10),
            child: GridView.builder(
              shrinkWrap: true,
              gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
                crossAxisCount: 5,
                  crossAxisSpacing:16,
                  mainAxisSpacing: 16
    
              ),
              itemCount: 50,
              itemBuilder: (context, index) {
                return GestureDetector(
                  onTap: (){
                    Navigator.push(
                      context,
                      MaterialPageRoute(builder: (context) =>  Verse()),
                    );
                  },
                  child: CircleAvatar(
                    backgroundColor:Colors.primaries[Random().nextInt(Colors.primaries.length)],
                    child: Text(index.toString(),style: TextStyle(
                        fontSize: 20,
                        color: Colors.white
                    ),),
                  ),
                );
              },
            ),
          ),
        );

  }
}

Answer 1

答案在这里

  static Future<List<Map<String, dynamic>>> gedata() async {
     final db = await Dbhelper().db;
     return db!.rawQuery('SELECT * from your table name);


   }

Flutter 从现有数据库 sqflite 中获取数据

Flutter fetch Data from existing database sqflite

dart

flutter

sqflite